Chem-phys

Question 1

What are 4 colligative properties?

Answer 1

vapor pressure lowering (depression)

boiling point elevation

freezing point depression

osmotic pressure

Question 2

What are ecplipsed conformations in newman projections?

Answer 2

the electrons in the front and back C-H bonds are closer together,

Question 3

What is the formula for density?

Answer 3

Density = mass/volume (DMV)

Question 4

What is the formula for centripetal acceleration (a_c)?

Answer 4

a_c​ = v²/r

Question 5

What are the 7 strong acids you should be familiar with?

Answer 5

1. HI hydroiodic acid
2. HBr hydrobromic acid
3. HCl hydrochloric acid
4. HNO₃ nitric acid
5. H₂SO₄ sulfuric acid
6. HClO₃ chloric acid
7. HClO₄ perchloric acid

Question 6

How do you determine the hybridization of an atom in a molecule?

Answer 6

1. Look at the atom.
2. Count the number of atoms connected to it (atoms – not bonds!)
3. Count the number of lone pairs attached to it.
4. Add these two numbers together.
   
   • If it’s 4, your atom is sp3.
   • If it’s 3, your atom is sp2.
   • If it’s 2, your atom is sp.
   • (If it’s 1, it’s probably hydrogen!)

Question 7

What two factors increase the speed of sound?

Answer 7

Increased temperature

non-compressible, or stiffer media

Question 8

What is the relationship between pKa, pKb, and pKw?

Answer 8

pKa + pKb = pKw = 14 at standard temperature 25 C

so a neutral/weak acid/base at standard temperature will be closer to 7

Question 9

What are microtubules used for in the cell?

Answer 9

Microtubules are used in the transport of vesicles and the positioning of organells within a cell

_{microtubules are composed of dimers of the protein tubulin}

Question 10

If gravitational force is causing rotational motion, what is the formula?

Answer 10

F_g = F_c

g = v²/r

Question 11

What is percent dissociation?

Answer 11

the percent dissociation of an acid/base is the percent of the original acid/base concentration that has dissociated into H+ or OH- ions

Question 12

what is the relationship between pH and [H⁺]?

Answer 12

pH = -log[H⁺]

[H⁺] = 10^-pH

Question 13

As a electron is moving to a lower energy shell, energy is ____

Answer 13

emitted (as a photon)

Question 14

What should an adequate buffer solution contain?

Answer 14

An adequate buffer solution should contain a weak acid and a similar (though not necessarily equal) molar amount of its conjugate base or vice versa

Question 15

What are good (strong) leaving groups?

Answer 15

Weak bases

Question 16

Why are pi bonds weaker than sigma bonds?

Answer 16

Pi bonds have a smaller overlapping electron region and, as a result, are weaker than sigma bonds

Question 17

What is the conversion factor for atm to Pa?

(atmosphere to pascals)

Answer 17

1 atm = 10⁵ Pa

Question 18

What is the angular momentum number (l) ?

Answer 18

describes the shape of the orbital

it can range from 0 to n-1 for a given principal quantum number

i.e. n = 4 shell

l = 0, 1, 2, 3

Question 19

What is an ester?

Answer 19

Question 20

What is the equation for power?

Answer 20

Power = Work/time

units = Watts (j/s)

Question 21

When is work path independent?

Answer 21

when conservative forces act on the system

Question 22

How would you calculate the number of possible stereoisomers in a molecule?

Answer 22

2ⁿ

n = number of stereocenters

Question 23

What goes into a michael addition reaction?

Answer 23

In a Michael addition reaction, an enolate attacks the beta carbon of an α,β-unsaturated aldehyde or ketone

_{In this mechanism, the carbon-carbon double bond is removed, which initially results in an enolate. The enolate’s negative alpha carbon is then protonated, leaving a structure with two carbonyl groups that are separated by three carbons. This process is shown below:​}

Question 24

If a ball take 3 seconds to reach the top of its vertical trajectory, how long does it take for the ball to drop back down?

Answer 24

Also 3 seconds.

Total time = 6 seconds

Question 25

What is the formula for carbonic acid?

Answer 25

H₂CO₃

Question 26

What equation do you use to calculate the engery added (or released) during a temperature change?

what about during a phase change?

Answer 26

Temperature Change:

Q (Heat added, kJ) = Mass (kg) * C (specific heat, kJ/kg*K°) ΔT(K°)

_{think MCAT}

_ΔT celsius is the same as _ΔT in degrees Kelvin (K = C + 270)

Phase change:

Q (heat added, kJ) = Mass (kg) * ΔH (enthalpy, kJ/kg)

_{*finding total energy, just follow the graph and add up the respective equations}

Question 27

what does “p” stand for in units like pH, pOH, pKa, etc.?

Answer 27

p stands for -log

i.e. pH = -log [H]

pOH = -log [OH]

pKa = -log [Ka]

Question 28

What is the relationship between pKa/pKb and Ka/Kb?

Answer 28

pKa = -log [K_a] –> -log [K_w/K_b]

pKb = -log [K_b] –> -log [K_w/K_a]

inverse relationship

remember p is the -log

_{Ka * Kb = Kw}

Question 29

How do we sense sound?

Answer 29

In terms of pressure

Question 30

What is the formula for Poiseuille’s law (in terms of flow)?

Answer 30

Question 31

What is the unit breakdown of Pa?

Answer 31

N/m²

Question 32

A electric field has a scalar or vector quantity?

Answer 32

vector

Question 33

Under 3 what conditions do chemical reaction favor the formation of the thermodynamic product over kinetic product?

Answer 33

• High temperatures
• Weaker, non-sterically hindered bases
• Reversible reactions

Question 34

What horizontal forces act on a moving tire found on a flat road?

Answer 34

Static Friction

the tires themselves are in constant, static contact with the ground under normal operation

The rotation of the tire moves the contact patch

The tire is pushing the road backwards and the road is pushing the tire forwards

Question 35

What are 5 different derivatives of carboxylic acid in order from least reactive (most stable) to most reactive (least stable)?

Answer 35

1. Carboxylate
2. Amide
3. Ester
4. Acid anhydride
5. acyl halide

Question 36

Name 4 elements that are common exceptions to the octet rule?

Answer 36

Beryllium (Be): can from 2 bonds for a total of 4 valence electrons

Boron (B): can form 3 bonds for a total of 6 valence electrons

Phosphorus (P): can form 5 bonds for a total of 10 valence electrons

Sulfur (S): can from up to 6 bonds for a total of 12 valence electrons

Xenon (Xe): can form up to 6 bonds for a total of 12 valence electrons

Question 37

A large rate constant (k) denotes what?

Answer 37

A large value fo the rate constant (k) means that the reaction is relatively fast

while small values of the rate constant means that the reaction is relatively slow

Question 38

What is electromagnetic force?

Answer 38

Electric force acts between all charged particles, whether or not they’re moving.

The magnetic force acts between moving charged particles.

Question 39

what is chromophore?

Answer 39

A chromophore is the part of a molecule responsible for its color. The color that is seen by our eyes is the one not absorbed by the reflecting object within a certain wavelength spectrum of visible light

Question 40

What is the formula for angular/rotational velocity (⍵)?

Answer 40

⍵ = Δθ/Δt

Δθ = change in angular roation

Δt = change in time

Question 41

As an electron jumps to higher shells it moves to ____ energy and becomes ____ stable

Answer 41

higher engery *

less stable

^{*(energy is absorbed)}

Question 42

What is a saturated compound?

Answer 42

compounds have only carbon-carbon single bonds (fully saturated with hydgrogen bonds)

Question 43

What is the forumla for work under the work-energy theorem?

Answer 43

Work = ΔKE = KE_final - KE_inital

Question 44

What is the formula for Reynolds number (Rn)?

Answer 44

Question 45

How should you combine rates (mathmatically)?

i.e. A + B – Rate 1 –> Y – Rate 2 –> Z

You want to find the total rate of A + B to Z?

Answer 45

multiply them

(rate 1)(rate 2)

Question 46

What is configurational isomers?

Answer 46

Stereoisomers that do not interconvert rapidly under normal conditions, and therefore are stable enough to be separated (i.e. c = c bonds have a flixed planar shape)

(include geometric isomers and chiral/optical isomers)

Question 47

What is a shortcut for finding the pH or pOH values given the concentration (M) of a solution?

Answer 47

(N x 10^±M) = (M±1).(10-N)

i.e HCl concentration of 4 x 10^-8 M has a pH of (8-1).(10-4) = 7.6 pH

Question 48

What is conjugation (chemistry)?

Answer 48

when 3 or more p orbitals join together into a larger “pi system”.

This tends to stablize molecules

exp. Alkenes with alternating carbon-carbon double bonds form conjugated systems

Question 49

Name a strong reducing agent and a weak reducing agent

Answer 49

• STRONG: LiAlH₄ (Lithium aluminum hydride)
• WEAK: NaBH₄ (Sodium borohydride)

Question 50

In basic conditions, balancing out redox reactions you will use ___ to balance out oxygen and ____ to balance out hydrogen

Answer 50

In basic conditions, balancing out redox reactions you will use HO- to balance out oxygen and H₂O to balance out hydrogen

Question 51

Why transition metals form colored compounds?

Answer 51

During this d-d transition process, the electrons absorb certain energy from the radiation and emit the remainder of energy as colored light. The color of ion is complementary of the color absorbed by it. hence, colored ion is formed due to d-d transition which falls in the visible region for all transition elements

(i.e. The color arises because nickel(II) ion has partially filled d orbitals and the electrons in the lower energy d orbitals absorb visible light to move to the higher energy d orbitals)

Question 52

How is boiling point defined?

Answer 52

Boiling point is actually the temperature at which P_vapor = P_atm

Question 53

The Venturi effect states that when a fluid starts moving faster, it exerts ____ pressure on its surroundings

Answer 53

The Venturi effect states that when a fluid starts moving faster, it exerts less pressure on its surroundings

Question 54

What is the mass of a neutron?

Answer 54

1 amu

Question 55

What are the rounded numerical values for:

1. sin(0)
2. sin(30)
3. sin(45)
4. sin(60)
5. sin(90)

Answer 55

1. sin(0) = 0
2. sin(30) = 0.5
3. sin(45) = 0.7
4. sin(60) = 0.9
5. sin(90) = 1

Question 56

In terms of pressure and volume, what is Joules?

Answer 56

Pascals (Pa) x cubic meters (m³)

Question 57

What is the equation for gibbs free energy (spontaneity)?

Answer 57

ΔG = ΔH - TΔS

ΔG is change in the free energy

ΔH is the change in enthalpy

ΔS is the change in entropy

T is temperature in kelvin

-ΔG means reaction is favorable and spontaenous

+ΔG means the reaction is unfavorable, nonspontaneous and needs energy from outside in order to proceed

ΔG = 0 means the reaction is at equilibrium

Question 58

What does static/kinetic force represent?

Answer 58

The amount of force needed to overcome friction

Question 59

What determines boiling point in alkanes?

Answer 59

When comparing alkanes, as molecular weight (size) increases, boiling point increases

Branching lowers boiling point slightly (so a linear alkane with x number of carbons will boil at a higher temperature than a branched alkane with x carbons

Question 60

What is the formula for Work?

Answer 60

work = Fdcos θ

F is the force applied

d is the distance over which the force is applied

θ is the angle between the force applied and the direction of the object’s movement

(if θ is 0, then cosθ is 1)

Question 61

What is the ionic charge of aluminum?

Answer 61

+3

Question 62

What is an alpha carbon?

Answer 62

the first carbon atom that attaches to a functional group

Question 63

What phases of matter are compressible? (i.e. gas, liquid, solid…)

Answer 63

Gases are compressible

gases have densitites that change according to the forces applied to them

liquids and solids are not compressible

Question 64

what us an enolate?

Answer 64

Question 65

What three things decrease surface tension? and why?

Answer 65

Temperature:

The average kinetic energy of the fluid molecules increases, so the surface tension is more likely to be able to break the intermolecular bonds holding the molecules together at the surface

Area:

molecules are stretched further apart, resulting in a thinner film of surface tension

Surfactant:

Their heads are polar (hydrophilic) and their tails hydrophobic. Important for lowering surface tension in lungs

Question 66

Is the atmospheric pressure at high altitudes higher or lower than at sea level?

Answer 66

atmospheric pressure at high altitudes are LOWER than at sea level

Question 67

What pathway (thermodynamic or kinetic) is more likely to dominate at higher temperatures?

Answer 67

The thermodynamically favored pathway is the one that forms the most stable product.

The kinetically favored pathway is the one with the lowest activation barrier because that allows the reaction to proceed the fastest.

At high temperatures, the thermodynamically favored pathway wins because it forms the most stable product, and at higher temperatures, there is sufficient energy to overcome the activation barrier.

Question 68

In regards to nomenclature and functional groups, how do you determine which side of a carbon chain is the “begining”?

Answer 68

Start on the side where the highest priority (highest oxidation state) functional group is closest

Question 69

What are electrical forces?

Answer 69

The repulsive or attractive interaction between any two charged bodies is called as an electric force

Generated by the voltage source and by the intrinsic electrical properties of the material

Question 70

What are enantiomers?

Answer 70

an enantiomer is one of two stereoisomers that are mirror images of each other that are non-superposable (like our hands)

Enantiomers differ at every chiral center

Question 71

For a monoprotic acid at the equivalence point, what equation should you use to understand the number of moles used in the analyate?

Answer 71

Molarity_base Volume_base = Molarity_acid Volume_acid

Question 72

Why do alkali metals serve as good reducing agents?

Answer 72

Due to their extreme tendency to lose a single electron and reach a noble gas configuration

Question 73

What is the conversion of atm to mmHg?

Answer 73

1 atm = 760 mmHg

1 atm = 760mmHg = 1 x 10⁵ Pa (N/m²) = 760 Torr

Question 74

What epimers?

Answer 74

a particular type of diastereomer which differ at only one stereocenter

Question 75

The buffer capacity of any buffer solution can be manipulated by changing what?

Answer 75

The molar amount of acid/base present in solution

Increasing the amount of acid/base present in solution will increase the ability of a buffer to resist changes in pH – meaning buffer capacity has increased.

Question 76

What is the difference between a sterocenter and a chiral center?

Answer 76

sterocenter – 3 or 4 substituents

Chiral center – 4 substituents

Question 77

Is N₂ an inert gas?

Answer 77

yes!

Question 78

What is the capital D/L configuration in organic chemistry?

Answer 78

a relative configuration given only to certain molecules such as carbohydrates and amino acids

Question 79

What is the difference between thermodynamics and kinetics?

Answer 79

Thermodynamics describes the overall properties, behavior, and equilibrium composition of a system. How stable they are in one state versus another (i.e. Gibbs free energy)

Kinetics describes the particular pathway by which a physical or a chemical change actually occurs. How quickly or slowly species react (i.e. activation energy)

Question 80

What is a spontaneous reaction?

Answer 80

a reaction that favors the formation of products at the conditions under which the reaction is occurring

Question 81

What is the unit breakdown of pascal (Pa)

Answer 81

one pascal is, 1 Pa = 1 kg · m-1 · s-2

Question 82

What are three shared characteristics between ketones and aldehydes?

Answer 82

1. polar
2. aportic (dont have hydrogen attached to N, O, F)
3. hydrogren bond acceptor
   
   1. oxygen can accept a hydrogen bond

Question 83

What is the formula for the Force of a spring?

Answer 83

F = -k * x

k = the spring constant

x = amount of extensions measured in meters

Question 84

What type of gas would fit the ideal gas model?

Answer 84

The ideal gas model does not account for attractive intermolecular forces or the volume of the gas molecules themsevles

therefore, this model is most applicable to real gases composed of:

small molecues that do not experiemce significant intermolecular interactions

Question 85

What is power?

Answer 85

Power is the rate at which work is done or energy is transferred in a unit of time.

Power is increased if work is done faster or energy is transferred in less time

Question 86

List the order of frequency from largest to smallest

Answer 86

Question 87

As an electron is moving to a higher energy shell, energy is ____

Answer 87

absorbed

Question 88

Is LDA (lithium diisopropylamide) a bulky molecule?

Answer 88

yes

Question 89

What are geometric isomers?

Answer 89

the connectivity between atoms is the same, but each molecules has different spatial arrangements of the atoms (typically seen in molecules with double bonds)

Cis–trans/E-Z isomerism, also known as geometric isomerism or configurational isomerism

Question 90

What is the bicarbonate buffer system

Answer 90

H₂O (aq) + CO₂ (g) ⇌ H₂CO₃ (aq) ⇌ H⁺ (aq) + HCO₃^- (aq)

Question 91

What is the bond angle for tetrahedral molecules?

Answer 91

109.5 bond angle

Question 92

what is an amine group?

Answer 92

Question 93

What determines an objects floatation?

Answer 93

Density

Question 94

What determines carbonyl reactivity?

Answer 94

The strength of the leaving group attached to the carbonyl

Question 95

What is the relationship with stability and basicity?

Answer 95

Inverse relationship

The more stable a molecule is – the weaker the base

The less stable a molecule is – the stronger the base

Question 96

order the following carboxylic acid derivatives from least reactive to most reactive

ester

amide

acid anhydride

acyl halide

Answer 96

Amides are the least reactive of the carboxylic acid derivatives, so they should be placed first.

Acyl halides are the most reactive, and thus should be placed last. We are now left with an ester and an acid anhydride.

Since the leaving group of the acid anhydride is resonance-stabilized, it will be a better leaving group, thus making the acid anhydride more reactive.

We therefore place the ester second and the acid anhydride third, yielding a final order of:

amide

ester

acid anhydride

acyl chloride

Question 97

What is deposition? (phase change)

Answer 97

gas –> solid

Question 98

What is the formula for surface tension?

Answer 98

T_S = force/distance

Question 99

What is an ether group?

Answer 99

Question 100

Order the following compounds by boiling point (highest to lowest)

Aldehydes

Ketones

Alcohols

Carboxylic Acids

alkanes

_{*substances of similar mass}

Answer 100

1. carboxylic acids
2. alcohols
3. ketones
4. aldehydes
5. alkanes

Question 101

List the prefixes of the metric system starting from the power of +/- 1 to +/- 12

Answer 101

tera = 10¹² / pico = 10^-12

giga = 10⁹ / nano = 10^-9

mega = 10⁶ / micro = 10^-6

kilo = 10³ / milli = 10^-3

hecto = 10² / centi = 10^-2

deca = 10¹ / deci = 10^-1

Question 102

What are tautomers?

Answer 102

structural isomers of chemical compounds that readily interconvert. This reaction commonly results in the relocation of a proton

Question 103

What is cohesive and adhesive forces in liquids?

Answer 103

Question 104

What are two formulas for capacitance?

Answer 104

C = Q/V (Q = CV)

C = A/d

Question 105

What is the lowercase d/l classification of organic molecules?

Answer 105

optical rotation of chiral molecules

An enantiomer that rotates plane-polarized light in the positive direction, or clockwise, is called dextrorotary [(+), or d-]

the enantiomer that rotates the light in the negative direction, or counterclockwise, is called levorotary [(-), or l-].

When both d- and l- isomers are present in equal amounts, the mixture is called a racemic mixture

The classification of a molecule as d or l has to be experimentally determined.

Question 106

In organic chemistry, what 4 types of bonds and their trends should you look for to see if a hydrocarbon chain is being reduced?

Answer 106

Reduction:

1. Increase C-H bonds
2. Decrease C-O bonds
3. Decrease C-N bonds
4. Decrease C-S bonds

Question 107

What are the numerical values for common sin/cos values (ie cos(90), sin(45), etc.)

Answer 107

Question 108

For ramps, how would you calculate mechanical advantage?

Answer 108

mechanical advantage = length of incline / height of incline

a value greater than (not equal to) 1 results in advantage

Question 109

What are the three types of thermodynamic systems?

Answer 109

1. isolated (does not exchange matter or energy)
2. closed (exchanges energy but not matter)
3. open (exchanges both matter and energy).

Question 110

How do you determine the pH of a solution?

Answer 110

calculated by taking the negative log of the proton concentration

Question 111

How are hemiketals/hemiacetals formed?

Answer 111

ketone/aldehyde + alcohol –> hemiketal/hemiacetal

Question 112

In organic chemistry, reactions under acidic conditions have intermediates that are:

postive or negative?

Answer 112

positive

remember that bronsted-lowry acids are proton donors, so the intermediates are more positive

Question 113

What is avogadros number?

Answer 113

6.02 x 10²³

the numnber of items (atoms, molecules, etc.) in one mole

Question 114

SN2 reactions are what order?

Answer 114

Second order

Second order reactions depend on the concentration of two species to the first power.

This is the minimal reaction order for any SN2 reaction, as the reaction rate must depend on at least the concentration of the nucleophile and the concentration of the substrate

Question 115

What is beta negative decay?

Answer 115

In beta minus (β−) decay, a neutron is converted to a proton, and the process creates an electron and an electron antineutrino

Question 116

What happens to the temperature during a phase transition (melting, boiling, etc.)

Answer 116

Temperature is constant during phase transitions, but the total energy contrinues to increase as heat enters the system

(since temperature directly reflects kinetic energy of the molecules in a system, the average kinetic energy is also contant during the transition)

Question 117

What is the

zeroth

first

second

and third laws of thermodynamics?

Answer 117

• zeroth law: if T_a=T_b and T_b=T_c then T_a=T_c
• first law: energy and matter cannot be created or destroyed in an isolated system
• second law:in any isolated system there is a natural tendency to become more and more disordered, or to detegenrate into a more disorded state. This precludes any and all efficient energy transfer (since that would imply a net entropy increase of zero).
• third law: crystals have no vibrational energy at absolute zero

Question 118

a solution with an H+ concentration of 10−4 M will have a pH of ___

Answer 118

4

Question 119

What amino acid can form disulfide bonds?

Answer 119

C (cys) cysteine

contains a thiol group (S-H)

_{*although M, Met, Methionine contains sulfur, it cannot form disulfide bonds because sulfur is bound to a carbon instead of a hydrogen and cannot easily lose its proton to forma. disulfide linkage through oxidation}

Question 120

What is an unsaturated compound?

Answer 120

having a double or triple bond

Question 121

What is a sulfonyl group?

Answer 121

Question 122

When is a solution considered neutralized?

Answer 122

A solution is considered “neutralized” when all of the protons and hydroxide ions in solution have been reacted with one another, and there is no excess.

For this to be the case, all acids in solution must be converted to their conjugate base.

Question 123

What three types of energy are accounted for with Bernoulli’s equation?

Answer 123

1. Pressure
2. Kinetic energy
3. gravitational energy

*the fluid form of conservation of energy

Question 124

What is an anomer?

Answer 124

cyclic monosaccharides or glycosides that are epimers, differing from each other in the configuration of C-1 if they are aldoses or in the configuration at C-2 if they are ketoses

Question 125

According to Graham’s law, what is the forumla for the rate of effusion?

Answer 125

gases mixed together in the same container at the same temperature only depend on their molar mass for their rate of effusion.

Question 126

What is the difference between dissassociation reactions and decomposition reactions?

Answer 126

A dissociation reaction involves the break down of molecule into component atoms or molecules

the decomposition reaction involves the break down of a substance into other substances

Dissociation reactions are notably different from decompositions in that they are generally reversible, existing in equilibrium

Question 127

What is a sulfoxide group?

Answer 127

Question 128

What is the relationship between acid/base chemistry and the common ion effect seen in solubility?

Answer 128

Question 129

What is the difference between a sterocenter and a chiral center?

Answer 129

A stereocenter is an atom bound to at least three unique groups such that a new stereoisomer is formed if two of these groups are switched (seem in double bonds – E/Z orientations)

A chiral center must have four unique substituents (chiral centers are a form of sterocenters – all chiral centers are sterocenters but not all sterocenters are chiral centers)

Question 130

What is the formula for Poiseuille’s law (in terms of changing pressure)?

think flow

Answer 130

Q is flow rate

ΔP is pressure drop

r is radius

η is fluid viscosity

L is length of tubing

Question 131

What is an enamine?

Answer 131

An enamine is an unsaturated compound derived by the condensation of an aldehyde or ketone with a secondary amine

enamines are formed from secondary amines and either aldehydes or ketones

Question 132

What is the formula for bicarbonate?

Answer 132

HCO₃^-

Question 133

What are lactams?

Answer 133

Cyclic amides are called lactams.

Lactams are named sequentially down the Greek alphabet (alpha, β, γ or ẟ, etc) according to which carbon is bonded to the ring nitrogen (you can also think about this as the number of carbons in the ring).

For example, a lactam with two carbons, alpha and β to the carbonyl, is called a β-lactam. A lactam with four carbons, alpha, β, γ, and ẟ, is called a ẟ-lactam.

Question 134

What is the difference between ferromagnetic and paramagentic?

Answer 134

• In a ferromagnetic element, electrons of atoms are grouped into domains in which each domain has the same charge. In the presence of a magnetic field, these domains line up so that charges are parallel throughout the entire compound.
  
  • form permanent magnets
  • contain atoms with uniform and non-random spin
• Paramagnetism refers to the magnetic state of an atom with one or more unpaired electrons
  
  • temporary magnet
  • contain atoms with random/non-uniform magnetic spins

_{Diamagnetic atoms have no magnetic spin whatsoever.}

Question 135

what is the SI base unit for temperature?

Answer 135

Kelvin

Question 136

What is Power?

Answer 136

Power = Work (j)/Time (s)

Question 137

Define mechanical work

Answer 137

the amount of energy transferred by a force

Question 138

increasing velocity, increases or decreases pressure?

Answer 138

increasing velocity decreases pressure

Question 139

What is a constitutional (structural) isomer?

Answer 139

molecules that share the same molecular formula (number and types of atoms) but the atoms are connected in a different order.

Question 140

What happens to the acceleration of an object as it falls?

Answer 140

Its acceleration will increase until terminal velocity is achieved as a result of the force of air resistance. At the point, acceleration will be 0

Question 141

What kind of product does the Robinson annulation reaction contain?

Answer 141

The product of a Robinson annulation should contain a six-membered ring with an α,β-unsaturated ketone

Question 142

What is a carbonyl?

Answer 142

Question 143

What is an amine?

Answer 143

amines are compounds and functional groups that contain a basic nitrogen atom with a lone pair

Question 144

What is a hemiacetal?

Answer 144

Question 145

What are two examples of non-conservative forces?

Answer 145

• Friction
• Air Resistance

Question 146

What formula would you use to find distance when given acceleration, time, and inital velocity?

Answer 146

d= v_i(t) + (1/2)at²

Question 147

List the order of wavelength from largest to smallest

Answer 147

1. ​Radio
2. Microwave
3. IR (infared)
4. Red
5. … Blue
6. UV
7. X-Rays
8. Gamma

Question 148

What happens when a subshell is one electron away from being half or fully filled?

Answer 148

Half-filled and fully-filled are more stable than subshells with any other number of electrons

We might expect copper to have the electron configuration [Ar]5s²4d⁹, but the 4d subshell steals an electron from the 5s orbital, resulting in the electron configuration [Ar]5s¹4d¹⁰

Question 149

What is bond order?

Answer 149

Bond order is the number of chemical bonds between a pair of atoms and indicates the stability of a bond. For example, in diatomic nitrogen, N≡N, the bond order is 3; the C−H bond order is 1.

Question 150

What is the formula for specific rotaton of optical activity?

Answer 150

Question 151

What is the continuity equation? (flow)

Answer 151

the flow into a pipe is equal to the flow coming out of it

A₁V₁ = A₂V₂

A = area

V = velocity

_{area of a circle = πr²}

Question 152

What is sublimation?

Answer 152

solid –> gas

Question 153

What is the reaction of a carbonate (Na₂CO₃) and water?

Answer 153

In water, carbonate will undergo the following reaction:

CO3^2–(aq) + H₂O(l) → HCO₃–(aq) + OH^–(aq) –> basic

Question 154

What is angle strain in organic chemistry?

Answer 154

angle strain occurs when the angle between single-bond carbon atoms deviates from 109.5°

(remember newman projections)

Question 155

What is a hemiketal?

Answer 155

Question 156

What is the gauche conformation in newman projections?

Answer 156

Description given to two substitutents attached to adjacent atoms when their bonds are at 60° with respect to each other

Question 157

What is the bond angle of a molecule with a bent shape?

Answer 157

104.5° bond angle

Question 158

What is the force due to air resistance?

Answer 158

F_{air resistance} = (V_terminal)²

Question 159

in the IUPAC naming system, how are carboxylic acids attached to cyclic compounds named?

Answer 159

In the IUPAC naming scheme, carboxylic acids attached to cyclic compounds are named by the attached cyclic hydrocarbon first (in this case cyclopentane), followed by the suffix “carboxylic acid”

“cyclopentanecarboxylic acid”

Question 160

In oxidative phosphoylation, cytochrome c acts as a #electron carrier?

Answer 160

a 1-electron carrier

Question 161

What are nucleophiles?

Answer 161

Electron rich species (-)

Donates electrons

Question 162

How do you add resistors in a series circuit?

Answer 162

Question 163

When a reaction is unfavorable/unstable, the reaction will _____ energy

Answer 163

absorb

Question 164

How do you add resistors in a parallel circuit?

Answer 164

Question 165

What unit is work measured in?

Answer 165

Joules

Question 166

What are the rules for assigning priority for the configuration of geometric isomers (E-Z configuration)

Answer 166

Question 167

UV radiation excites _____?

Answer 167

UV Radiation excites nonbonding electrons such as lone pairs or electrons in pi bonding

Question 168

in the IUPAC naming system, how are substituents ordered?

Answer 168

alphabetically

Question 169

What is K_a, K_b, and K_w?

Answer 169

K_w deals with the auto-ionization of water (meaning that water interacting with water will yield some H3O+ and OH- molecules along with water – but still neutral because the acids/bases cancel each other out)

K_a and K_b deal with how well an acid/base will disassociate. So a higher K value, means a stronger acid or base becuase it favors product disassociation

Question 170

A primary alcohol mixed with a strong oxidizing agents will yield what?

Answer 170

a carboxylic acid

_{weak oxidizing agents will only yield aldehydes from primary alcohols}

Question 171

What is beta plus decay?

Answer 171

beta plus (β+) decay, a proton is converted to a neutron and the process creates a positron and an electron neutrino. β+ decay is also known as positron emission

Question 172

What are the units in a voltage?

Answer 172

joules/coulombs

(measures electric potential)

Question 173

What is the equation for enantiomeric excess

Answer 173

enantiomeric excess = (observed optical rotation x 100) / specific rotation

Question 174

What unit is defined as the strength of the magnetic field where 1 coulomb of charge is able to experience 1 Newton of force while moving 1 meter per second. This is otherwise written as N x s / (C x m)?

Answer 174

Tesla

Question 175

When is magnetic force maximized?

Answer 175

Magnetic force is maximized when an object’s velocity vector is perpendicular to the magnetic field lines.

Conversely, magnetic fields cannot act on objects with a velocity vector whose direction is parallel to the direction of magnetic field lines.

Question 176

How do you calculate the total work done in a Pressure • Volume curve (graph)?

Answer 176

the total work done is the area enclosed by the PV curve

*in this case, find the area of the triangle –> the integral

Question 177

Why do alcohols have a higher boiling point than aldehydes/ketones?

Answer 177

aldehydes/ketone display intermolecular dipole-dipole interactions between the carbonyl carbons and oxygens

while alcohols are capable of hydrogen bonding, a stronger type of intermolecular dipole interaction

Question 178

Order the following carboxylic acid dertivatives from least stable to most stable

esters

amides

acyl halides

acid anhydrides

carboxylates

carboxylic acid

Answer 178

remember that acyl chlorides have the most electropositive carbonyl because of the electronegative chloride, and are the most reactive; they also have the most stable leaving group (Cl-),

followed by acid anhydrides,

followed by esters (which are about the same reactivity as carboxylic acids),

and then the almost entirely unreactive amides, since NR2 stabilizes the carbonyl via resonance delocalization of its lone pair and is a horrendous leaving group.

And don’t forget that carboxylates, the conjugate base of carboxylic acids, are the most stable of the bunch!

Question 179

What is viscosity?

Answer 179

the property of liquids by which they are resistant to flow, or the resistance to deformation by shear stress.

On the molecular level, viscosity is caused by friction between layers of the fluid that are in motion relative to each other

Question 180

are alcohols more or less acidic than water?

Answer 180

alcohols are LESS acidic than water

Question 181

When an object is accelerating through a turn, what are the forces a play?

Answer 181

normal force – force exterted by the ground (mass * gravity), verticle force

acceleration force – force from the turn (mass * accleration), horizontal force

these forces form a right triangle, so to find the overal force, calculate the hypotenuse with the legs F_normal = mg and F_turning = ma

Question 182

What is torsional strain in organic chemistry?

Answer 182

torsional strain is created by eclipsing substituents on neighboring atoms

Question 183

What should the pKa of an ideal indicator be for a titration?

Answer 183

it is desirable that the pKa of a chosen indicator be within +/- 1 unit of the target pH (the titration end point)

for titrations studying weak acids titrated with a strong base, the endpoint titration will occur at a pH greater than 7

• strong acid titrated with a strong base has a endpoint pH at neutral 7*
• weak base titrated with a strong acid yields an endpoint pH of below 7*

Question 184

PV/nRT, temperature is calculated in what?

Answer 184

kelvins

Question 185

What is the equation for mechanical advantage?

Answer 185

inclined planes provide a mechanical advantage of greater than 1

Question 186

What is M (molarity)

Answer 186

moles/liter

Question 187

Define in vitro

Answer 187

describe work that’s performed outside of a living organism

Question 188

Define conservative forces

Answer 188

Forces that are path-independent, meaning that the amount of work done by a conservative force does not depend on its path (focus on displacement).*

Conserves energy

_{<em>*only care about starting and ending state</em>}

Question 189

Chemical compounds ending in “-one”, “-en”, and “-ol” willl typically be part of the majority of what type of hormone?

Answer 189

Steroid hormones (hydrophobic, and insoluble in water)

i.e. aldosterone, estrogen, testosterone, cortisol

Question 190

A system that produces heat is _____ that heat energy

Answer 190

A system that produces heat is losing that heat energy

Question 191

What is an imide group?

Answer 191

Question 192

In titration reactions, what is the equivalence point?

Answer 192

The equivalence point of a solution is the point where the moles of analyte originally in the solution are equal to the moles of titrant added to the solution.

Question 193

Why are hydrostatic pressure changes for liquids linear?

Answer 193

this is becayse as depth changes, the density of the liquid remains constant

in comparison, gases have densities that change according to the forces applied to them (gases are compressible, but liquids and solids are not compressible)

Question 194

How do you determine the r/s configuration of a chiral center when looking at a fischer projection?

Answer 194

orient the lowest priority (4th) substituent on the top using one of the two rotation options shown below.

then draw a curve from the highest priority (1st) to the third priority substituent, and if its clockwise its R and if its counterclockwise its S

Question 195

What are lactones?

Answer 195

Cyclic esters are called lactones

They are named using the letters of the Greek alphabet in the same way.

Two examples are shown below, with the carbons labeled with their corresponding Greek letters.

Question 196

If two gases have the same temperature, do they share the same average or total KE?

Answer 196

Average kinetic energy

total kinetic energy is an extrinsic property as it depends on the number of molecules present

Question 197

What biological molecule can the Robinson annulation be useful in synthesizing?

Answer 197

steroid hormones

Because it is used to make six-membered rings, Robinson annulation is useful in synthesizing steroid hormones, which have three fused six-membered rings.

Testosterone and estrogen, shown below, are go-to examples of steroid hormones for the MCAT

Question 198

What is the purpose of using optical rotation (rotations of plane-polarized light)?

Answer 198

measure the concentration or enantiomeric ratio of chiral molecules in solution. Allows for analyzing/gathering information about a substance

Question 199

What is surface tension?

Answer 199

it represents the amount of energy required to increase the surface area of a liquid.

Surface tension is the tension created at the liquid’s surface by the intermolecular forces between molecules

Question 200

What is the formula for chemical equilibrium?

Answer 200

Question 201

Atomic emission and absorption spectra are ____ for each element.

Answer 201

unique

Question 202

What is the formula for Kinetic Energy?

Answer 202

KE = 1/2mv²

Question 203

What is the fischer projection of ribose?

Answer 203

5 carbons (forms furanose ring)

aldehyde functional group

sugar group found in RNA

Question 204

What is the equation for combustion?

Answer 204

Fuel + O₂ → CO₂ + H₂O

Question 205

Define non-conservative forces

Answer 205

Forces that exact a certain energetic cost per distance

Question 206

What are the rounded numerical values for:

1. cos(0)
2. cos(30)
3. cos(45)
4. cos(60)
5. cos(90)

Answer 206

1. cos(0) = 1
2. cos(30) = 0.9
3. cos(45) = 0.7
4. cos(60) = 0.5
5. cos(90) = 0

Question 207

Watts (W) are a unit of ___

Answer 207

power

Question 208

Area of a circle?

Answer 208

A = πr²

Question 209

What is a chirality?

Answer 209

property of asymmetry

an object or a system is chiral if it is distinguishable from its mirror image; that is, it cannot be superimposed onto it

(like our hands)

*if a carbon atom has 4 unique substituents, it is chircal center

Question 210

A joule is equivalent to what?

Answer 210

Newton * meters

Question 211

What is force?

Answer 211

F = mass x acceleration

Question 212

What is the law of conservation of mass? (2 aspects)

Answer 212

mass in an isolated system is neither created nor destroyed

charge in an isolated system is neither created nor destroyed. It can only be transferred from one system to another

Question 213

What is K_a/K_b relationship with K_eq?

Answer 213

K_a/K_b = K_eq

Question 214

What are the units in current?

Answer 214

coulombs/second

Question 215

A vast majority of metal oxides are in what phase at standard temperatures?

Answer 215

solid

Question 216

Where are nonmetals found in the periodic table?

Answer 216

the right side

Question 217

What kind of lens is used to correct myopia (nearsightedness)?

Answer 217

a diverging lense (concave)

Question 218

What is an aromatic compound?

Answer 218

Any of a large class of unsaturated chemical compounds characterized by one or more planar rings of atoms joined by covalent bonds of two different kinds (i.e. benzene)

Question 219

What is the formula for the force of kinetic or static friction?

Answer 219

F = µ_k/sN

µ_k/s = coefficient of kinetic friction or static friction

N = Normal force

Question 220

What is vaporization?

Answer 220

liquid –> gas

Question 221

Why is solid H2O (ice) less dense than its liquid phase (water), allowing it to float ontop?

Answer 221

the bent structure of the water molecule and ratio of covalently-bonded hydrogens to lone pair electrons on the oygen atom maximizes the hygrogen bonding that occurs in the solid phase

this produces a hexagonal strucutre with large empty spaces

Question 222

When a shell jumps from a high energy shell to low energy shell, a photon is ____

High –> Low

Answer 222

emitted

Question 223

In acidic conditions, balancing out redox reactions you will use ___ to balance out oxygen and ____ to balance out hydrogen

Answer 223

In acidic conditions, balancing out redox reactions you will use H₂O to balance out oxygen and H⁺ to balance out hydrogen

Question 224

As the size of an atom or molecule increases what happens to the intermolecule forces?

Answer 224

as the size of an atom or molecules increases, it becomes easier to create temporary dipoles, which increases the intermolecular forces associated with the interactions of molecules

Question 225

A reaction where the H_f of the products is greater than the H_f of the reactants will lead to a ____ value for ΔH_reaction and be endo or exo thermic?

Answer 225

A reaction where the H_f of the products is greater than the H_f of the reactants will lead to a positive value for ΔH_reaction and be endothermic

ie H_fproducts = 10 j/mo

H_freactions = -18 j/mol

H_products > H_reactants

Question 226

What is an imine?

Answer 226

An imine is a functional group or chemical compound containing a carbon–nitrogen double bond

Imines are formed from primary amines and either aldehydes or ketones

Question 227

How do you find the standard enthalpy of a reaction?

Answer 227

_{refers to the enthalpy change of a reaction under standard conditions, meaning at 1 atmosphere of pressure and 25°C}

ΔH°_reaction = ΔH°_products - ΔH°_reactants

Question 228

What is K_p?

Answer 228

Equilibrium constant Kp is equal to the partial pressure of products divided by partial pressure of reactants and the partial pressure are raised with some power which is equal to the coefficient of the substance in balanced equation

Question 229

What is the principal quantum number?

Answer 229

the principal quantum number, n, is most closely associated with the potential energy of the electron

it is a measure of the approximate radial size of an electron cloud

Question 230

What is the equation for velocity experienced during circular motion?

Answer 230

Question 231

What is a meso compound?

Answer 231

despite containing two or more stereogenic centers, the molecule is not chiral. A meso compound is “superposable” on its mirror image (i.e. achiral)

contains an internal plane of symmetry

Question 232

Do bulkier substituents prefer axial or equatorial positions?

Answer 232

equatorial positions – less angle strain

Question 233

reactions that proceed from gas to liquid to solid are endothermic or exothermic?

Answer 233

exothermic

gases have more heat energy than liquids and liquids have more heat energy than solids

Question 234

What is the SI unit for current?

Answer 234

Ampere

Question 235

What is an amide group?

Answer 235

nitrogen attached to carbonyl

Question 236

When the pH of a solution is below the pKa value of the compound, in what form will the compound primarily exist?

Answer 236

When pH is below pKa –> the environment is considered acidic and the compound will exist predominately in its protonated form

When pH is above pKa –> the group is in the conjugate base form (deprotonated)

Question 237

What is the angle of incidence equal to?

Answer 237

The angle of incidence always equals the angle of reflection

Question 238

As temperatures decrease, what happens to the the H2O in the air?

Answer 238

with decreasing temperatures, air is able to hold less H2O

since colder air can hold less H2O, this means the same relative humidity would result in less total water in the air

so air has significantly less mass of H2O per unit volume at higher altitudes as temperatures drop

Question 239

What are Newtons?

Answer 239

A derived unit of force (kg*m/s²)

Question 240

What is the periodic trend for acidity?

Answer 240

• acidity increases going down a column (group)
  
  • the size increases going down, so the bond length increases allowing the atom to more readily give up its H+ bond
• Acidity increases going across a row (period)
  
  • electronegativity increases
  • those atoms want to hold onto electrons (electron acceptor, proton donor)

Question 241

Why are metallic solids good conductors of heat and electricity?

Answer 241

The delocalized valence electrons in metallic solids give metals the ability to conduct heat and electricity

_{metallic solids consist of a positive atomic core that is surrounded by delocalized electrons}

Question 242

How does pH work with Le Châtelier’s principle?

Answer 242

This deal with the common ion effect

remember that pH is determined by H+ concentration. A high H+ concentration means a low pH, and a low H+ concentration (high OH- concentration) means a high pH

exp. decreasing the acidity of the solution (removing the disassociating H+ ions) can help weak acids reaction move towards the products (since we’ve removed the H+ product)

Question 243

What is an ampere?

Answer 243

Current

Charge/time

Coulombs/second

Question 244

What is the product of a michael addition reaction?

Answer 244

1,5-dicarbonyl is the product of a Michael addition.

ketone/aldehyde + α,β-unsaturated ketone or aldehyde + (base) –> 1,5-dicarbonyl

It is an intermediate in a Robinson annulation

_{<em>The Robinson annulation = Michael addition + intramolecular aldol condensation = cyclic alpha,beta-unsaturated carbonyl compound.</em>}

Question 245

What is the definition of a Brønsted-Lowry acid/base?

Answer 245

A Brønsted-Lowry acid is any species that is capable of donating a proton— H+

A Brønsted-Lowry base is any species that is capable of accepting a proton, which _requires a lone pair of electrons t_o bond to the H+

amphoteric means it can act as both a Brønsted-Lowry acid and a Brønsted-Lowry base

Question 246

What do colligative properties depend on?

Answer 246

Colligative properties, such as freezing point depression and boiling point elevation, only depend on the total number of solute particles dissolved in a solution.

Question 247

Which direction do electric field lines move?

Answer 247

Electric field lines move from a positive to a negative direction

(i.e. electric field lines move from outside to inside an axon as the axon has a negative membrane potential)

Question 248

What is a thiol?

Answer 248

Question 249

How do you add capacitors in a series circuit?

Answer 249

Question 250

What does conductance and resistance depend on?

Answer 250

Conductivity and resistivity depend on material properties of an object,

while conductance and resistance also depend on the length and cross section surface area of an object

Question 251

What are ortho- , meta- , and para- substituents?

Answer 251

main patterns by which substituents “direct” electrophilic aromatic substitution

“para” – parallel

“ortho”– like teeth close together

“meta” – the inbetween

Question 252

Under what 3 conditions do chemical reaction favor the formation of the kinetic product over thermodynamic product?

Answer 252

• Low temperatures
• strong, sterically hindered bases
• irreversible reactions

Question 253

What is the equation for torque?

Answer 253

T = rFsin(ø)

T = torque

r = radius/distance

F = force

Question 254

An object is dropped from a height and you want to determine what its maximum speed is. What formula do you use?

Answer 254

Before the object is dropped KE = 0 and PE = total energy

When the object is dropped, and PE converts to KE, at maxium speed, PE = 0 and KE = total energy

KE = 1/2mv²

PE = mgh

set KE = PE

Question 255

What happens to atmospheric pressure as you get closer to sea level?

Answer 255

It increases

Question 256

What is a thioketone group?

Answer 256

Question 257

What happens to the pH at the equivalence point of a tritration when working with a weak acid and a strong base titrant?

Answer 257

pH is greater than 7 because a weak acid yields a stronger conjugate base (in comparison to a strong acid). This stronger conjugate base adds to the basicity of the solution

Question 258

How do we measure the intensity of sound? (formula)

Answer 258

Intensity_sound = Power (W) / Area (m²)

Question 259

a negative ΔG values corresponds wtih a K_eq values that is greater, less, or equal to 1?

Answer 259

greater than

ΔG = -ln K_eq

-ΔG –> forward reaction favored

K_eq > 1 –> products favored

Question 260

What is the fischer projection of fructose look like?

Answer 260

6 carbons (forms furanose)

ketone functional group

OH on C3 on the left

Question 261

What is the relationship between partial pressure and mole fraction?

Answer 261

Question 262

Why are thiols more acidic than alcohols?

Answer 262

the sulfur atom is larger than the oxygen atom.

This has two effects:

(1) it makes the S-H bond longer and weaker than the O-H bond and so favours loss of H+
(2) it means that the conjugate base of the thiol is more stable than that of the alcohol because the negative charge is spread out over a larger surface area so lowering the charge density in the thiolate (S-) compared to the alkoxide (O-)

Question 263

What is the E-Z classification system for organic molecules?

Answer 263

E-Z isomerism specifies the orientation of the two highest priority substituents (not necessarily identical to each other, like in cis-trans)

(Z) isomer: two highest priority substituents on the same side (Ze Zame!)

(E) isomer: two highest priority substituents on the opposite side

Question 264

What is the density of water?

Answer 264

Question 265

How do you add capacitors in a parallel circuit?

Answer 265

Question 266

What is the magnitude of charge in an electron/proton?

Answer 266

1.6 × 10^-19 coulombs

Question 267

What is the kinematics equation for distance?

Answer 267

d = ((V_f + V_i)/2) * t

Question 268

If a process is not efficiently utilizing work in the body, the excess energy is likely to be lost as what?

Answer 268

Heat

Question 269

what is the anti conformation in newman projections?

Answer 269

the most stable conformation, the two methyl groups lie as far apart from each other as possible with a dihedral angle of 180 degrees

Question 270

What happens when an electron moves farther away from the nucleus?

Answer 270

Less attractive forces from the protons

therefore, more energy

therefore, less stable

Question 271

What is the definition of a Lewis acid/base?

Answer 271

Lewis acid is an electron-pair acceptor

Lewis base is an electron-pair donor.

Question 272

What is the definition of combustion?

Answer 272

a compound reacts (burns)

Question 273

What is the fischer projection of glucose look like?

Answer 273

6 carbons

aldehyde functional group

OH on carbon 3 on the left

Question 274

What is sound?

Answer 274

longitudinal, compressive waves that propagate through a transmission medium such as a gas, liquid or solid

Question 275

what is the difference between intermolecular forces and intramolecular forces

Answer 275

Intramolecular forces are the forces that hold atoms together within a molecule.

Intermolecular forces are forces that exist between molecules

Question 276

What three things should you consider when debating between SN1 and SN2 reactions?

Answer 276

Image contains answers

SN1 is a two step rxn, with a carbocation intermediate

SN2 is a one step rxn where the nucleophile must attack from behind (remember sterics)

Question 277

What direction will an electron move in respect to electric field lines?

Answer 277

A negatively charged particle such as an electron will move in the direction opposite the direction of the electric field lines

_{<em>electric field lines point away from positive charges and toward negative charges</em>}

_{<em>think of forces in respect to the proton</em>}

Question 278

What is the formula for Power?

Answer 278

Power = work/time

or

Power = ΔKE/time

Question 279

What is a positive control?

Answer 279

a positive control is a control group that is not exposed to the experiemntal treatment but that is exposed to some other treatment that is known to produce the expected effect

Question 280

What is the formula for the energy per photon?

Answer 280

Energy = hf

h = plancks constant

f = frequency

Question 281

what are reducing sugars?

Answer 281

have free aldehyde or ketone –> commonly seen with monosaccharide or disaccharide/polysaccharides with free aldehyde/ketone at the end

Question 282

In what situation do paramagnetic atoms have uniform spin?

Answer 282

Paramagnetic atoms have a uniform magnetic spin when a magnetic field is applied to them

Question 283

What is the difference between resistance and resistivity?

Answer 283

Resistivity is a property inherent to a material

Resistance that changes with shape (R = L/A)

Question 284

anion with one more oxygen atom than the -ate anion uses the prefix ____

Answer 284

per-

Question 285

Why are eclipsed conformations unfavorable? (give 2 reasons)

Newman projections

Answer 285

Bulky substiuents experience tosional strain

more potential energy

Question 286

In ideal gas behavior, what should you expect in terms of the volume of the gas particle and its intermolecular forces with other gas particles?

Answer 286

The gas particles have negligible volume

The gas particles are equally sized and do not have intermolecular forces (attraction or repulsion) with other gas particles

The gas particles move randomly in agreement with Newton’s Laws of Motion.

The gas particles have perfect elastic collisions with no energy loss.

Question 287

Define hydrolysis

Answer 287

the chemical breakdown of a compound due to reaction with water

Question 288

What is the chemical formula for hydrogen peroxide?

Answer 288

H₂O₂

Question 289

What equation would you use to solve for distance given

velocity_i

acceleration

time

Answer 289

d = v_i(t) + (1/2) at²

Question 290

What is Saponification?

Answer 290

Saponification reactions involve the addition of an aqueous base (alkali) to a triglyceride to form fatty acid salts and a triol, glycerol

Question 291

In organic chemistry, reactions under basic conditions have intermediates that are:

postive or negative?

Answer 291

Negative

Bronsted-Lowry bases are proton acceptors, so they remove a proton making the intermediates negative

Question 292

What is an inert gas?

Answer 292

An inert gas is a gas that does not undergo chemical reactions under a set of given conditions (like the noble gases)

inert gases are used generally to avoid unwanted chemical reactions degrading a sample

Question 293

What is the equation for enthalpy?

Answer 293

Internal Energy (U or E) + Pressure • Volume

Question 294

What is the formula for gage pressure?

Answer 294

Question 295

What is the difference between atomic weight and mass number?

Answer 295

The mass number is the sum of protons and neutrons in an atom

Atomic weight is a term that tells us the weighted average mass of an atom of a certain element, accounting for all possible isotopes of that element

Question 296

What states (increased or decreased) are favorable for ideal gas behavior:

temperature

volume

pressure

Answer 296

increased temperature

increases volume

decreased pressure

Question 297

What is the structure of acetone?

Answer 297

carbon is sp² hybridized

trigonal planar geometry

120 degree bond angle

Question 298

What equation converts rotational velocity to linear velocity?

Answer 298

v = r*⍵

⍵ = rotational velocity

v = linear velocity

r = radius

Question 299

The (wavelength or frequency) of an electromagnetic wave does not change as it enters a new medium?

Answer 299

The frequency of an electromagnetic wave does not change as it enters a new medium

no wave peaks are appearing out of thin air; however often a peak hits the interface from the first medium must be the same as how often peaks are passing into the second medium

only wavelength can change in response to changing velocity

Question 300

What domain contains a golgi apparatus?

Answer 300

only eukarya have a golgi apparatus

Question 301

What is the doppler effect?

Answer 301

the doppler effect is the sound wave emitted by or reflected from a moving object. It will change frequency based on the relative speed of the object

Question 302

What is the volume of 1 mole of an ideal gas at STP (Standard Temperature and Pressure = 0 °C/273 °K , 1 atm)?

Answer 302

the volume of an ideal gas is 22.41 L/mol at STP

Question 303

What is the order of listing the quantum numbers of an electron?

Answer 303

n, l, m, s

Question 304

does carbon dioxide have a dipole moment?

Answer 304

No

it does have polar covalent bonds but the symmetrical linear structure does not produce a net dipole moment

Question 305

What kinematics equation should you use to solve for V_f if you’re given

V_i

acceleration

time

Answer 305

v_f = v_i + at

Question 306

What is the formula for carbonate?

Answer 306

CO₃^-2

Question 307

What is equation for centripetal Force?

Answer 307

F_c = mv²/r

Question 308

what is the formula for work?

Answer 308

also: Work = Power x time

(beccause Power = Work/time)

Question 309

What is ß-minus decay?

Answer 309

a neutron is converted to a proton as an electron emitted

(element is converted to an element with one additional proton)

Question 310

What is the Rydberg formula?

(predicts the difference in energy between two energy levels)

Answer 310

R[1/(n_f)² – 1/(n_i)²]

Question 311

what is a thioester?

Answer 311

Question 312

What are four examples of conservative forces?

Answer 312

• Gravitation
• Electromagnetic forces (electrostatic and magnetic)
• Spring Forces
• Pushing/Pulling Forces

Question 313

the suffix -ous represents an ion _______

Answer 313

with a lesser charge.

i.e. Fe³⁺ is ferrous ion

Fe²⁺ is ferric ion

Question 314

What is an ester group?

Answer 314

Question 315

What is the formula for calculating the magnitude of an electric field?

Answer 315

E = F/q_o

E = kQ/r²

where k is a constant with a value of 8.99 x 109 N m2/C2

Q is the source charge

q_o is the test charge

Question 316

What are gamma rays?

Answer 316

It consists of the shortest wavelength electromagnetic waves and so imparts the highest photon energy

gamma rays represent ionizing radiation

Question 317

What is the periodic trend for nucleophilicity?

Answer 317

• Nucleophilicity increases going down a column (group)
  
  • this is due to the size of the atom. it gets larger down a group, making the bond distance longer, i.e. weaker. more readily lets go
• Nucleophilicity decreases going across a row (period – left to right)
  
  • this is due to the size of the atom. it gets smaller across a period, making the bond distance short, i.e. strong. Doesn’t want to let go

Nucleophilcity: an atoms ability to give away electrons + bonds

Question 318

What is the main structure of steroid hormones/cholesterol?

Answer 318

a fused 4 ring system

Question 319

What is the fischer projection of glyceraldehyde?

Answer 319

3 carbons

aldehyde functional group

(like glucose cut in half)

Question 320

What can alter the K_eq (equilibrium constant) of a reaction?

Answer 320

temperature

changes in concentration, addition of catalyst/enzyme, pressure, volume will NOT change the equilibrium constant. It may distrurb the equilibrium (excluding the catalyst) of the reaction but not its constant

Question 321

How many electrons can each orbital hold

Answer 321

2 electrons

^{*this is regardless of energy level, shape, orbital, or orientation}

Question 322

What are the peak zones for OH functional groups in IR spectroscopy?

Answer 322

3200-3500 cm^-1

Question 323

What determines hydrocarbon reactivity?

Answer 323

electron density and/or electronegative leaving groups (i.e. Cl, Br, etc.)

reactivity increases as electron density is increased

Most reactive: triple bonds

least reactive: single bonds

Question 324

What are electrophiles?

Answer 324

Electron poor species (+)

Accepts electrons

Question 325

What is the chemical structure of phenol?

Answer 325

An aromatic, organic compound

benzene + alcohol

Question 326

What is the difference between a magnetic and electric field?

Answer 326

Both electric and magnetic fields are the consequence of the attraction and repulsion of electric charges.

However, a magnetic effect is caused by moving electric charges while an electric field is caused by stationary charges

Question 327

What is the formula that relates temperature and kinetic energy?

Answer 327

KE = 3/2kT

the average kinetic energy of a gas is directly related to its temperature.

thus the gas with the highest temperature will have the greatest kinetic energy

Question 328

What is an imine?

Answer 328

nitrogen double bonded to carbon

Question 329

What are the peak zones for C=O functional groups in IR spectroscopy?

Answer 329

~1700-1750

Question 330

What is the formula for nitrous oxide?

Answer 330

N₂O

Question 331

What is the formula use to calculate the magnitude of the electric field between the plates?

Answer 331

E = V/d

Question 332

Why are alpha hydrogens more acidic in aldehydes than ketones?

Answer 332

When dealing with aldehydes and ketones, remember that alpha protons–those bonded to carbon atoms adjacent to the carbonyl carbon–are weakly acidic

a ketone has two alkyl groups that are bound to the carbonyl carbon.

Since alkyl groups are electron-donating, these add excess electron density to the carbonyl carbon. This added “partial negative” charge destabilizes the negative charge of the conjugate base, making the alpha protons less acidic

Question 333

What is vacuum distillation?

Answer 333

vacuum distillation lowers the boiling point of a substance by reducing the atomspheric pressure through the introduction of a vacuum

often used when components have very high boiling points and would be otherwise difficult ot distill

Question 334

Is HCN an acid or base?

Answer 334

Hydrogen cyanide is weakly acidic with a pKa of 9.2

It partially ionizes in water solution to give the cyanide anion, CN−.

A solution of hydrogen cyanide in water, represented as HCN, is called hydrocyanic acid.

Question 335

what is a thioether group?

Answer 335

Question 336

What is the fischer projection of galactose look like?

Answer 336

6 carbons (forms pyranose ring)

aldehyde functional group

OH on C3 and C4 on the left side

Question 337

What is the kinematics equation for acceleration?

Answer 337

a = (V_f - V_i) / t

Question 338

What is the formula for the force experienced by a charge moving through a magnetic field?

Answer 338

F_magnetic = qvB sin(θ)

• charge q
• moving at a speed v
• in a magnetic field of strength B
  
  • 1 Tesla =1 (N) / [C*(m/s)] = 1 (N) / (A*m)
• θ is the angle between the directions of v and B

Question 339

In organic chemistry, what 4 types of bonds and their trends should you look for to see if a hydrocarbon chain is being oxidized?

Answer 339

Oxidation:

1. Decrease C-H bonds
2. Increase C-O bonds
3. Increase C-N bonds
4. Increase C-S bonds

Question 340

What is a triglyceride?

Answer 340

Question 341

When light enters a more dense medium it will bend ___ the normal

Answer 341

When light enters a more dense medium it will bend towards the normal

Question 342

What should the pKa of an ideal buffer solution be around? (not a numerical value)

Answer 342

The pKa of an ideal buffer should be exactly at the pH that you are interested in buffering at, but pKa’s within a narrow range around the desired pH (e.g. +/- 1) are still acceptable

Question 343

Define in vivo

Answer 343

when research or work is done with or within an entire, living organism.

Examples can include studies in animal models or human clinical trials

Question 344

What is Poiseuille’s Law?

Answer 344

Flow = (ΔPπr⁴ )/ (8Lη)

ΔP is the pressure difference across the pipe

r is the radius of the pipe

L is the length of the pipe

η is the viscosity of the fluid in the pipe

Question 345

List the various spatial conformations of cyclohexane in order from most stable to least stable (chair, boat, etc.)

Answer 345

most stable

1. chair
2. twist boat
3. boat
4. half chair

Question 346

What is the formula for boiling point elevation?

Answer 346

ΔT = iK_bm

where m is the molality of the solution (Molality = mol solute (i.e. NaCl) / kg solvent (i.e. water))

i = the ionization number (i.e. NaCl splits into two ions, so i = 2)

K_b is a constant value for the solvent

Question 347

The suffix -ic represents an ion ____

Answer 347

with a greater charge

i.e. Fe²⁺ is ferric ion

Fe³⁺ is ferrous ion

Question 348

What is the equation for the energy of a photon related to its wavelength?

Answer 348

E = hc/λ

h = planck’s constant (6.62 x 10^-34 J•s)

c = speed of light (3 x 10⁸ m/s)

Energy is measured in eV

λ is measured in meters

Question 349

What is a urea group?

Answer 349

Question 350

What is the purpose of boiling chips?

Answer 350

When transition from liquid to gas during boiling, the liquid needs nucleation sites (places to start forming bubbles).

This is achieved by either scratching the insde of the flask or using boiling chips

It provides nucleation sites that give the liquid a place to start forming bubbles to prevent superheating

Question 351

What are the 8 strong bases you should be familiar with?

Answer 351

1. NaOH sodium hydroxide
2. KOH potassium hydroxide
3. Ca(OH)₂ calcium hydroxide
4. NH₂^- (conjugate base of ammonia)
5. H^- hydride
6. CH₃O^- methoxide
7. CH₃CH₂O^- ethoxide
8. (CH₃)₃CO^- tert-butoxide or t-butoxide

Question 352

how does sublimation work?

Answer 352

sublimation is the transfer of solid directly to gas (does not have to pass through a liquid phase)

for purification, sublimation of water under reduced pressure keeps mixtures cold (which can be helpful during protein extraction as it the cold temperature keeps them in their native state)

Question 353

A magnetic field has a scalar or vector quantity?

Answer 353

vector

Question 355

What type of acids/bases require an ICE table when calculating pH, concentration, moles, etc.?

Answer 355

weak acids/bases

because they do not fully dissociate in water

Question 356

List three common oxidizing agents and three common reducing agents

Answer 356

Question 357

What are three different equations that calculate conductance (how well an object allows for the flow of electrical charge)?

Answer 357

Question 358

What kinematics equation should you use on an object in free fall if you’re looking for distance given time

Answer 358

y = (1/2)gt²

Question 359

What are three things to consider when discussing and comparing boiling points?

Answer 359

1. the strength of intermolecular forces (hydrogen bonding, dipole, etc.)
2. number of carbons (more carbons = increasing bp)
3. branching (more branching = decreasing bp)

Question 360

How are anhydrides named?

Answer 360

Asymmetrical anhydrides are named according to both their constituent carboxylic acids in alphabetical order,

(in this case ethanoic propanoic anhydride)

If the anhydride is symmertrical (i.e. propanoic acid on either side), then you would just name it propanoic anhydride

Question 361

How does stability relate to thermodynamics and kinetics?

Answer 361

Reaction thermodynamics are dictated by the stability of the reactants compared to the products.

Reaction kinetics are dictated by the activation barrier, which is determined by the stability of reaction intermediates

Question 362

What is the definition of a arrhenius acid/base?

Answer 362

An Arrhenius acid is any species that increases the concentration H+—or protons—in aqueous solution (exp. HCl)

An Arrhenius base is defined as any species that increases the concentration of hydroxide ions, OH−, in aqueous solution (exp. NaOH)

Question 363

anion with one fewer oxygen atoms than the -ite anion uses the prefix ____

Answer 363

hypo-

Question 364

What are conformational isomers?

Answer 364

Conformational isomers are stereoisomers that can be converted into one another by rotation around a single bond

single bonds that can rotate without being broken

Question 365

oxidizing agents often inlcude what two elements?

Answer 365

oxygen (O)

chromium (Cr)

Question 366

What is the difference between diamagnetic and paramagnetic?

Answer 366

Question 367

A reaction with pyridinium chlorochromate (PCC) and alcohol yield what?

Answer 367

Primary alcohols yield aldehydes

Secondary + alcohols yield ketones

Question 368

What is steric strain?

Answer 368

Steric strain is caused by substituents (even hydrogen substituents) getting in each other’s way

Question 369

higher frequency denotes ____ energy

Answer 369

higher frequency denotes higher energy

Question 370

What molecule are alkali metals highly reactive with?

Answer 370

water

Question 371

When comparing kinetically favored vs thermodynamically favored reactions, at what temperature would a reaction become more thermodynamically favorable?

Answer 371

Room temperature (25 C) and above

Question 372

What is the formula for hydrostatic pressure?

Answer 372

Hydrostatic pressure = ρgh

ρ = density of fluid (not the object)

g = gravity

h = height

Question 373

What is nitric oxide?

Answer 373

NO

Question 374

What is the Reynolds number?

Answer 374

The Reynolds number (Re) helps predict flow patterns in different fluid flow situations.

At low Reynolds numbers, flows tend to be dominated by laminar (sheet-like) flow, while at high Reynolds numbers flows tend to be turbulent.

Question 375

How do you calculate log (w/o a calculator)

Answer 375

Question 376

when does splicing occur in transcription?

Answer 376

removal of introns and splicing of exons is a step in the production of mature mRNA from the transcript produced from DNA (pre-mRNA)

DNA –> mRNA

Question 377

What is the Hell-Volhard-Zelinsky reaction?

Answer 377

A carboxylic acid reacts with PBr₃, Br₂, H₂O to yield a carboxylics acid with a Bromine on the alpha carbon

this strengthens the acidity of the carboyxylic acid because of the inductive effect from the electronegative bromine, pulling electron charge away from the carboxylic functional group and stabilizing the conjugate base

Question 378

what is an analog?

Answer 378

A drug whose physical structure is related to that of another drug.

Although they have similar physical properties, analogs can have very different chemical and biological properties

Question 379

What is the relationship between frequency and pitch?

Answer 379

high-frequency sounds correspond to high pitch

low-frequency sounds correspond to low pitch

Question 380

What is the formula to coulombs law?

Answer 380

Question 381

What is the relationship between pH and pOH at standard temperatures?

Answer 381

pH + pOH = 14

(pH + pOH = pK_w)

_{pH and pOH can fall among values lower and higher than 0 and 14!}

Question 382

What is the difference between intensity and loudness in regards to sound?

Answer 382

loudness has to do with how the intensity of sound is perceived

Question 383

What is the mass of a proton?

Answer 383

1 amu

Question 384

What kinematics equation should you use if you’re looking for final velocity given distance (free fall)?

Answer 384

V_f² = 2gy

or V_f = √ 2*gy

Question 385

What is the area of a triangle?

Answer 385

A = (H_b * B) / 2

Question 386

what is a disulfide group?

Answer 386

Question 387

What is a hydronium ion?

Answer 387

Question 388

What is the formula involving the relationship between the speed of light, wavelength, and frequency?

Answer 388

c = λf

(remember c = speed of light is m/s, and that λ is meters and f is 1/s^-1)

c is the speed of electromagnetic waves in a VACUUM!

Question 389

What are the 4 fundamental forces? (in order of increasing strength)

Answer 389

Least Strong

1. Gravitational force
2. Electromagnetic force
3. Weak nuclear force
4. Strong nuclear force

Most Strong

Question 390

What is fusion?

Answer 390

solid –> liquid

aka melting

Question 391

What is the relationship between Ka, Kb, and Kw?

Answer 391

(Ka)(Kb_conjugate) = Kw

a strong acid yields a weak conjugate base

a weak acid yields a strong conjugate base

** remember that a strong conjugate base does not make a strong base! there are 8 strong bases to remember for the MCAT

Question 392

Reactions that proceed from solid to liquid to gas are endothermic or exothermic?

Answer 392

endothermic

gases have more heat energy than liquids and lieuqids have more heat energy than solids

Question 393

Which classification for acid/base will the MCAT primarily test you on, unless stated otherwise?

Answer 393

The Brønsted-Lowry system (wherein an acid acts as a proton donor and a base acts as a proton acceptor) is the standardly used one for the MCAT.

Unless an AAMC question specifies otherwise, presume acid-base terminology is referring to the Brønsted-Lowry definition.

Question 394

What is the relationship between K_eq and spontaneity?

Answer 394

K_eq = 0 : equilibrium

K_eq < 1 : Nonspontaneous/reverse reaction favored

K_eq > 1 : Spontaneous/forward reaction favored

_{Keq cannot be less than 0}

Question 395

According to the kinetic molecular theory (ideal gas behavior), the pressure of a sample of gas comes from collisions what two things?

Answer 395

the kinetic molecular theory asserts that the pressure of a gas is due to the elastic collisions between gas particles and the walls of the container

Question 396

What is the forumla for centripetal force (F_c)?

Answer 396

F_c = (mv²) / r

Question 397

A strong acid yields a ____ conjugate base

Answer 397

Strong acid = stable conjugate base (i.e weak conjugate base)

^{think resonance when thinking of a molecules stability}

Question 398

Where are the metals found in the periodic table?

Answer 398

the left side

Question 399

What two orientations can the substituents of cyclohexane be in?

Answer 399

Axial orientation (sticking up or down from the ring)

Equatorial orientation (extending in the approximate plane of the ring)

Question 400

A Watt is equivalent to what?

Answer 400

Joules/second

unit for power

Question 401

what are the products of the Hell-Vollhard-Zelinsky halogenation reaction followed by hydrolysis?

Answer 401

Question 402

What is a stereoisomer?

Answer 402

Stereoisomers are isomers that differ in spatial arrangement of atoms, rather than order of atomic connectivity

Question 403

What kind of lens is used to correct hyperopia (farsightedness)?

Answer 403

converging (convex)

Question 404

a solution with an OH− concentration of 10−9 M will have a pOH of ___

Answer 404

9

Question 405

What formula should you use to break down velocity into its x (horizontal) and y (vertical) components?

Answer 405

v_ix = v_i(cos(θ))

v_iy = v_i(sin(θ))

Question 406

What is the formula for sulfurous acid?

Answer 406

H₂SO₃

Question 407

What is the Pauli exclusion principal?

Answer 407

no two electrons in a given atom can have the EXACT same four quantum numbers

Question 408

In an aldol reaction, consisting of two different reactancts, (i.e. a ketone + aldehyde, ketone 1 + ketone 2, etc.) a minimum of how many reactions take place?

Answer 408

ketone + aldehyde –> aldol

1. ketone (elec) + aldehyde (nuc)
2. ketone (nuc) + aldehyde (elec)
3. ketone + ketone
4. aldehyde + aldehyde

remember that the alpha carbon of aldehydes/ketones can act as either a nucleophile or electrophile

Question 409

Where are alkali metals located on the periodic table?

Answer 409

the first column

Question 410

When does something boil?

Answer 410

the temperature at which the vapor pressure of a solution is EQUAL to the atmospheric pressure (external pressure)

Question 411

Is chemical equilibrium (K_eq) deal with kinetics or thermodynamics?

Answer 411

Thermodynamics!!

Question 412

When a reaction is favorable/leads to a more stable molecule/atom, it ____ energy

Answer 412

releases

Question 413

What is the equation for ΔG using enthalpy and entropy?

Answer 413

ΔG = ΔH - TΔS

Question 414

What do you have to consider when doing nuclephilic/electrophilic substition? or any organic reaction?

Answer 414

Sterics

Where can this compound fit?

Question 415

What happens to H₂CO₃ in water?

Answer 415

H₂CO₃ is a weak acid and is unstable in nature.

It undergoes partial dissociation in the presence of water to yield H+ and HCO^3– (bicarbonate) ions

Relative H2CO3 concentration is really CO2 (aq) in equilibrium with water.

Question 416

What is the formula of work in a fluid system?

Answer 416

Work = (Pressure)(ΔVolume)

Question 417

By what factor does the concentration of protons change in response to a pH decrease of 1?

Answer 417

a factor of 10

Question 418

what are the products of the Hell-Vollhard-Zelinsky halogenation reaction?

Answer 418

Question 419

what is a functional isomer?

Answer 419

constitutional isomers bearing different functional groups

Question 420

What does A, B, and C represent on this phase diagram?

Answer 420

Question 421

What is DMSO (dimethyl sulfoxide)?

Answer 421

a common polar aprotic solvent

Question 422

What are diastereomers?

Answer 422

a type of a stereoisomer

Diastereomers are defined as non-mirror image non-identical stereoisomers

Question 423

What is the correlation between the shell, subshell, # orbitals, and # of electrons?

Answer 423

Question 424

What is formula for sulfuric acid?

Answer 424

H₂SO₄

Question 425

What is the difference between electron geometry and molecular geometry?

Answer 425

Electron geometry describes the arrangement of electron groups

Molecular geometry describes the arrangement of atoms, excluding lone pairs

Question 426

In the electron transport chain, electrons are passed from species with ___ positive reduction potentials to ___ positive reduction potentials

Answer 426

In the electron transport chain, electrons are passed from species with less positive reduction potentials to more positive reduction potentials

(i.e. cytochrome C = +22 Volts . . . O₂ = +82 Volts)

Question 427

What is the equation for electrical force?

Answer 427

F = Eq

E is the strength of the electric field

q is the charge

Question 429

what is an anhydride?

Answer 429

the compound obtained by removing the elements of water from a particular acid

An acid anhydride is a compound that has two acyl groups bonded to the same oxygen atom

Question 430

what is the formula for a decible (dB) aka sound intensity?

Answer 430

Question 431

What happens to voltage in a parallel circuit?

Answer 431

Voltage is the same across each component of the parallel circuit

Question 432

What is the equation for gibbs free energy at equilibrium?

Answer 432

Question 434

What are the units for electric field strength (E)?

Answer 434

N/C

Newtons/Coulomb

Question 435

What are the SI base units for:

time

length

mass

electric current

temperature

amount of substance

Answer 435

Question 436

What is pitch?

Answer 436

Frequency

The sensation of a frequency is commonly referred to as the pitch of a sound.

A high pitch sound corresponds to a high frequency sound wave and a low pitch sound corresponds to a low frequency sound wave

Question 437

what are the units for joules?

Answer 437

N*m

newton * meters

Question 438

What is the equation for tension at angle on a string?

Answer 438

T₁ = T₂(Cosθ₂ / Cosθ₁)

Remember that on the x-axis, the two opposing tensions should cancel out, so therefore:

T₁(Cosθ₁) = T₂(Cosθ₂)

which when rearranged gives us the equation above

(on the y-axis, both tension forces should cancel out with the force from the weight of the box (m*g), therefore, T₁(Sinθ₁) + T₂(Sinθ₂) = m*g)

Question 439

What is the power of a lens?

Answer 439

Question 440

What is the equation for sound intensity?

Answer 440

The intensity in decibels = 10 * log10 (intensity/ intensity of zero decibels)

I = sound intensity.

I₀ = sound intensity of zero decibels= 10-12 W/m-2

Question 441

A standing wave is moving through a pipe – what is its velocity of the air at a node?

Answer 441

velocity = 0

the air is still

Question 442

True or false: the water displaced by an object is equal to the volume of that object

Answer 442

true

Question 443

What equation should you consider when looking at the conversion of mass and energy?

Answer 443

E = mc²

c = speed of light (3 x 10⁸)

Question 444

What form of energy is always conserved?

Answer 444

Total energy

Question 445

What is the relationship between the radius of a lens and its focal distance?

Answer 445

f=2r

The relation between focal length (f) and radius of curvature (R) of a spherical mirror is that the focal length is equal to half of the radius of curvature

Question 446

Magnetic fields always exert a force on a moving particle that is ______ to both the particle’s velocity and the field itself

Answer 446

Magnetic fields always exert a force on a moving particle that is perpendicular to both the particle’s velocity and the field itself

Question 447

How does the right hand rule change when a charge is negative?

Answer 447

Question 448

What is a chiral center?

Answer 448

A carbon atom with four non identical substituents

Question 449

How do you determine the number of stereoisomers in a molecule?

Answer 449

Count the number of chiral centers (carbon atom with 4 distinctly different substituents) and use the 2^n rule (n = number of chiral centers)

Question 450

A substance is insoluble in water but will dissolve if the solution is acidic. This behavior is typical of substances that feature ____ anions?

Answer 450

Basic anions! The substance is likely basic

Question 451

When silver is reduced (Ag2+ —> Ag(s)) what visual reaction occurs?

Answer 451

Shiny silver mirror! (Tollens Test)

Question 452

What is a hemiacetal functional group?

Answer 452

Question 453

In disaccharides, which functional group can ring open and form an aldehyde that will reduce a compound such as Ag+?

Answer 453

Hemiacetal

Question 454

What is the conversion factor for 1 m³ and 1 cm³

Answer 454

1 m³ = 10⁶ cm³

1 m³ = 10⁹ mm³

Question 455

What physics effect allows ultrasounds to produce the images they do?

Answer 455

the doppler effect

The Doppler effect in ultrasound waves is used to provide fetal images.

The Doppler effect relates the frequency of the ultrasound wave as detected by a moving detector to the frequency of the wave when the source is stationary, the speed of the source, and the speed of the detector.

Question 456

What is the principal quantum number (n)?

Answer 456

The principal quantum number, n, describes the energy of an electron and the most probable distance of the electron from the nucleus.

In other words, it refers to the size of the orbital and the energy level an electron is placed in.

Question 457

What is the orbital quantum number (l)?

Answer 457

The approximate shape of an electron cloud

his quantum number provides the subshell designators s, p, d, and f

Question 458

What is the relationship between resistance and temperature?

Answer 458

If the temperature of a metal conductor increases, the ions of the metal vibrate more vigorously. This increases the number of collisions between the free electrons and the ions.

Hence, for a metal, resistance increases with increasing temperature

Question 459

Myopia (nearsightedness) is cured using what type of lens?

Answer 459

a diverging lens (concave lens)

Question 460

a person’s weight in water can be understood as:

Answer 460

the difference between the body density and water density

Question 461

What is the breakdown units for coulombs in terms of joules?

Answer 461

1 coulomb = 1 joule/volt

Question 462

For a buffer to be good, what should its pka be in reference to the pH of the desire experiemental condition? (the pH you want in the end)

Answer 462

Good experimental design protocols state that a good buffer has a pKa within 1 pH unit of the desired experimental conditions

Question 463

What is released during alpha, beta, and gamma decay?

Answer 463

radiation is the emission or transmission of energy in the form of waves or particles

A atom goes through some kind of radation and is broken down a bit to emit energy.

In alpha decay, basically a molecule helium is released

In beta decay, an electron is released

in gamma decay, high energy gamma ray is released

Question 464

What is the difference between B^- decay and B⁺ decay?

(DONT LOOK AT THIS PICTURE UNTIL YOU REVEAL ANSWER)

Answer 464

Question 465

What equation relates energy and frequency?

Answer 465

The energy equation is E = hν

E represents energy,

h represents Planck’s constant (6.626 x 10 -34 J · s)

v represents frequency.

The energy equation is a direct relationship between frequency and energy because as frequency increases, so does energy

Question 466

What is an isotope

Answer 466

Isotopes are two or more types of atoms that have the same atomic number (number of protons) and position in the periodic table, and that differ in nucleon numbers due to different numbers of neutrons in their nuclei (different atomic mass)

Question 467

What are three different lens equations you should be familiar with?

Answer 467

1/f = (n-1)[1/R1 – 1/R2]

where f is the focal length, n is the refractive index of the lens material, and R1 and R2 are the front and back radii of curvature

1/f = 1/i + 1/o

where o is the distance from the object to the lens, and i is the distance from the lens to the image (i.e. the distance at which the image will be clear)

M = h_i/h_o = - d_i/d_o

M = magnefication (no units)

h_i = height of image

h_o = height of object

d_i = distance from image

d_o = distance from object

P = 1/f

p = power

Question 468

light coming into the human eye should be focused on the ____ and ____ of the eye

Answer 468

the fovea and retina

The human fovea is where most of the rods and cones are concentrated. These receptors are stimulated by the light coming through the eyes and are responsible for visual perception

Question 469

the focal point (f) is positive or negative for diverging lenses?

Answer 469

f is negative for diverging lenses

Question 470

the focal point (f) is positive or negative for converging lenses?

Answer 470

f is positive for converging lenses

Question 471

What is the difference between reverse phase and normal phase chromatography?

Answer 471

In normal-phase chromatography, the stationary phase is polar and the mobile phase is nonpolar. In reversed phase we have just the opposite;

the stationary phase is nonpolar and the mobile phase is polar.

Question 472

What is a fully eclipsed conformation in a newman projection?

Answer 472

The fully eclipsed conformation is clearly the highest in energy and least favorable since the largest groups are interacting directly with each other.

Question 473

What is an oxidizing agent that can convert alcohols to carbonyls?

Answer 473

PCC (Pyridinium chlorochromate)

It converts alcohols to carbonyls, but is not strong enough to convert a primary alcohol into a carboxylic acid.

It only converts primary alcohols to aldehydes, and secondary alcohols to ketones.

Question 474

How can a grignard reagent be synthesized?

Answer 474

adding an alkyl halide (i.e. CH3Br) to a vessel containing diethyl ether and small pieces of solid Mg

Question 475

What is the Doppler equation for frequency?

Answer 475

Δf/f = -v/c

Δf is the apparent change in frequency,

f is the original frequency,

v is the velocity of the observer with respect to the stationary source,

c is the speed of the wave.

Question 476

What is the doppler effect equation?

Answer 476

Question 477

A charged particle ____ through an electric field

Answer 477

accelerates

Question 478

What is the equation for the pressure of fluids?

Answer 478

Pressure = (density)x(height)x(gravity)

Question 479

What is the formula for the number of possible peptides that contain one each of N number of amino acids?

Answer 479

n!

(N factorial – i.e. For n = 3 (a tripeptide), n! = 3! = 3 × 2 × 1 = 6 possible peptide combinations)

Question 480

What is the formula for a uniform electric field?

Answer 480

E = Vd

V = voltage

d = distance

(E =f/q)

Question 481

What is the structure of benzoquinone?

Answer 481

Question 482

What is the structure of hydroquinone?

Answer 482

Question 483

when resistors are in parallel, what happens to voltage?

Answer 483

The voltage remains the same for resistors in a parallel circuit

(current gets split up)

Question 484

When resistors are in a series, what happens to current?

Answer 484

Current remains the same

(voltage differs for resistors in series)

(current splits when resistors are in parallel)

Question 485

What are phosphatides and where are they prevalent?

Answer 485

Phosphatides or phospholipids are a class of lipids and are a major component of all biological membranes

All phospholipids contain a diglyceride, a phosphate group, and a simple organic molecule such as choline. They are a type of molecule. They form a lipid bilayer within a cell membrane.

Question 486

What is phosphonic acid?

Answer 486

consists of a single pentavalent phosphorus covalently bound via single bonds to a single hydrogen and two hydroxy groups and via a double bond to an oxygen

Phosphorous acid is the compound described by the formula H₃PO₃

This acid is diprotic, not triprotic as might be suggested by this formula.

Phosphorous acid is an intermediate in the preparation of other phosphorus compounds

Question 487

What is pyrophosphate?

Answer 487

pyrophosphates are phosphorus oxyanions that contain two phosphorus atoms in a P–O–P linkage

It is important for the healthy function of connective tissues such as bones, cartilage, and joints

Question 488

How do you calculate the R_f value in paper chromatography?

Answer 488

Question 489

is a dehydration reaction an SN1 or SN2 reaction?

Answer 489

It is an SN1 reaction – a carbocation forms

not a stereospecific reaction

Question 490

how do enzymes affect chemical reactions?

Answer 490

An enzyme stabilizes the transition state, thus lowering the activation energy of a reaction.

Question 491

What happens to the percent ionization (dissociation) of a reaction when it is diluted?

Answer 491

The percent dissociation of an acid varies with the concentration of the acid. The more dilute an acid is, the greater the percent ionization

Question 492

what is the formula for index of refraction?

Answer 492

n = c/v

c = 3 x 10⁸

Question 493

what is the intensity (energy) of electromagnetic radiation proportional to?

Answer 493

The energy of electromagnetic radiation is directly proportional to the number of photons

the intensity of electromagnetic radiation is defined as energy emitted per unit time. Thus, intensity is directly proportional to the number of photons emitted

Question 494

What are the prefixes for units?

Answer 494

Question 495

What is atmospheric pressure in mmHg and Pa?

Answer 495

760 mmHg

1 atm

1 x 10⁵ Pa

Question 496

What is the molar volume of an ideal gas?

Answer 496

The molar volume of an ideal gas at 25°C is 24.4 L

Question 497

what type of enzyme cleaves peptide bonds?

Answer 497

Peptidases or proteases

Question 498

In glycogen, how are the glucose subunits connected? (what type of bond)

Answer 498

In glycogen, each glucose subunit is connected to an adjacent glucose subunit by an α-1,4-glycosidic bond

Question 499

In glycogen, what type of bond occurs at the branching points?

Answer 499

α-1,6-glycosidic bonds

Question 500

In cellulose, what type of glycosidic bond occurs?

Answer 500

β-1,4-Glycosidic bond

Question 501

In starch, what type of glycosidic bond occurs?

Answer 501

α-1,4-Glycosidic bond

Question 502

What glycosidic bonds occur in cellulose, starch (amylose and amylopectin), and glycogen – respectively

Answer 502

Question 503

Regardless of mass, if a catalyst has a greater surface area exposed, that will do what to the reaction?

Answer 503

The rate will be faster because a greater surface area of catalyst will be exposed

Grinding a heterogeneous catalyst increases the amount of catalyst available to the reaction and therefore increases its rate

Question 504

at what value for E° does a reaction occur spontaenously?

Answer 504

E° is greater than 0

Question 505

When oxidizing a compound, what happens to -SH?

Answer 505

When oxidixing a compound, -SH becomes deprotonated and disulfide bonds form

Question 506

What kind of bond is involved in scaffolding?

Answer 506

Intermolecular bonds

Question 507

When a phosphate group is attached to a molecule – where will it bond?

Answer 507

The phosphate group will bond to the hydroxyl group on the molecule

Question 508

What three amino acids are capable of phosphylation?

Answer 508

Serine (Ser, S)

Threonine (Thr, T)

Tyrosine (Tyr, Y)

the phosphate attaches to the hydroxyl group of the side chains of these amino acids

Question 509

What element is made up of graphite?

Answer 509

Carbon

(when graphite is under extreme pressure, it becomes a diamond)

Question 510

What is the henderson hasselbach equation?

Answer 510

pH = pKa + log([A^-]/[HA])

When the acid (HA) and its conjugate base (A^-) have equal concentrations (log(1) = 0), the pH = pKa

Question 511

What is mutarotation?

Answer 511

Mutarotation is the change in the optical rotation because of the change in the equilibrium between two anomers, when the corresponding stereocenters interconvert. Cyclic sugars show mutarotation as α and β anomeric forms interconvert

Question 512

What is tautomerism?

Answer 512

Tautomerization is a net process by which protons are transferred from one site to another by a series of steps in which the solvent is an intermediary

Question 513

What is a dipolar ion?

Answer 513

an ion charged both positively and negatively (like an amino acid in solution)

+H3NCH2COO− of glycine — called also zwitterion.

Question 514

What happens to organic molecules when they absorb ultraviolet light?

Answer 514

Excitation of bound electrons

Ultraviolet-visible absorption is a process where a molecule absorbs ultraviolet or visible light that excites electrons (makes them high energy). This energy causes an electronic transition from a ground state (non excited) to an excited state

Question 515

The half-life of a radioactive material is the time it takes _____?

Answer 515

the time it takes for half of all the radioactive nuclei to decay into their daughter nuclei

the half-life of a radioactive material is defined as the time it takes for half of all the radioactive nuclei to decay into their daughter nuclei, which may or may not also be radioactive

Question 516

What kind of radioactive phosphates are present in ATP?

Answer 516

Question 517

What is the venturi effect?

Answer 517

The Venturi effect is the reduction in fluid pressure that results when a fluid flows through a constricted section (or choke) of a pipe.

Question 518

In an electrochemical cell, where does reduction/oxidation occur? (Think anode and cathode)

Answer 518

oxidation always occurs at the anode

reduction at the cathode of an electrochemical cell

Question 519

What is the equation for work done by a spring?

Answer 519

W = 1/2kx²

W = Fx

F_spring = kx

(think about taking the integral when you plug in F, thats where the 1/2 comes from)

Question 520

What type of reaction takes place in a battery (in a circuit)?

Answer 520

a redox reaction (chemical reaction)

Question 521

how is energy converted along a circuit?

Answer 521

Chemical to electric to thermal

chemical (battery is redox reaction)

electric (current converts energy to electric)

thermal (heat dissipates as we have resistance)

Question 523

What is the equation for volumetric flow rate?

Answer 523

Q = vA

Q = volumetric flow rate

v = velocity

A = cross sectional area

Question 525

What is the unit breakdown for the equation Q = VC?

Answer 525

Q = VC

Q = Charge (Coulombs)

V = Voltage (V)

C = Capacitance (Farads - F)

Question 526

What is the equation for energy stored in a capacitor?

Answer 526

U = 1/2CV²

U = energy (joules)

C = capacitance (farads)

V = voltage (volts)

Question 527

Boiling points measure the stability of what time of interaction?

Answer 527

Boiling point measures the stability of INTERmolecular interactions

Question 528

The relative thermodynamic stability of isomeric organic compounds can be inferred from what?

Answer 528

heat of combustion

the thermodynacmic stability of a compound is determined by its intramolecular forces

the lower the heat of combustion – the more stable the compound (less heat produced)

Question 529

In its ground state, an element is in its lowest or highest electron configuration?

Answer 529

its lowest

Question 530

What happens to electric field lines in a uniform electric field?

Answer 530

electric field lines are equally spaced in a uniform field.

Question 531

Will diluting a buffer change its pH?

Answer 531

no

Question 532

What is the byproduct of a peptide bond formation?

Answer 532

water (H₂O)

Question 533

What is this chemical structure?

Answer 533

Heme (like that in hemoglobin)

heme is a porphyrin. The basic unit of a porphyrin is the pyrrole ring, a five-sided heterocycle containing one nitrogen atom

Question 534

A log₁₀(X) or ln(X) where X < 1 produces a positive or negative number?

Answer 534

A log₁₀(X) or ln(X) where X < 1 produces a NEGATIVE number

Question 535

A log₁₀(X) or ln(X) where X > 1 produces a positive or negative number?

Answer 535

A log10(X) or ln(X) where X > 1 produces a POSITIVE NUMBER

Question 536

log₁₀(0) and ln(0) is equal to what?

Answer 536

log₁₀(0) does not exist

ln(0) does not exist

Question 537

galvanic cells are sponatenous or nonspontaenous?

Answer 537

galvanic cells are spontaenous

E^o > 0

Question 538

electrolytic cells are sponatenous or nonspontaenous?

Answer 538

nonspontaneous

E^o < 0

Question 539

what is the formula for specific gravity?

Answer 539

density of object / density of fluid = specific gravity = %of object submerged in liquid

Question 540

What are three mechanisms in which enzymes bind to its substrate?

Answer 540

Ping pong mechanism

ordered sequential mechanism

random mechanism

Question 541

What is the ping-pong mechanism in enzyme catalytics?

Answer 541

Ping Pong – also called the double placement reaction – means that one or more products are released before all substrates bind the enzyme.

A ping pong mechanism is when, considering an enzyme that forms two products from two substrates, binds to substrate 1 first, releases the first product, and then binds to the second substrate and forms the second product. Since the substrates bind at different times, no ternary complex is formed

Question 542

What is the ordered mechanism in enzyme catalytics?

Answer 542

this occurs when an enzyme has multiple substrates to bind in a reaction

In this mechanism, both substrates must bind to the enzyme before any products are made and released. The substrates might bind to the enzyme in a random fashion (A first then B or vice-versa) or in an ordered fashion (A first followed by B)

Question 543

What is random sequential mechanism in enzyme catalytics?

Answer 543

this occurs when an enzyme has multiple substrates to bind in a reaction

In this mechanism, both substrates must bind to the enzyme before any products are made and released. The substrates might bind to the enzyme in a random fashion (A first then B or vice-versa) or in an ordered fashion (A first followed by B)