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AAMC Material > CHEM/PHYS > Flashcards

CHEM/PHYS Flashcards

1
Q

What are characteristics associated with dehydration reactions ?

A

Dehydration reactions:
- tertiary alcohol readily dehydrate
- form carbocation intermediate
- involves loss of water molecule
- mixture of cis and trans products
- NOT Stereospecific

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2
Q

What functional group represents a peptide bond?

A

AMIDE group

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3
Q

What makes nucleophilic substitution slower ?

A

When there is crowding of groups at a carbon (steric hindrance)

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4
Q

In Gas chromatography, what is the first peak to emerge?

A

The Least Polar, Most Volatile compound will be first to emerge

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5
Q

what kind of compounds are very volatile ?

A

compounds that have LONDON dispersion forces

(meanwhile hydrogen bonds are least volatile)

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6
Q

What are the differences between SN1 and SN2 ?

A

To be continued (find out)

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7
Q

Compare and contrast the signs of diverging vs converging lens ?

A

Diverging lens (negative sign)
converging lens (positive sign)

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8
Q

What is thin lens formula ? What are units ?

A

Thin lens formula : 1/focal length = 1/ object + 1/ image

Units : D (diopter) 1D = 1m ^-1

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9
Q

How does an enzyme work ?

A

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

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10
Q

What can decrease the percent ionization (dissociation of ions) of a compound ?

A

Adding a STRONG ACID that will increase the amount of H+ in solution and ( thus decrease the percentage ionization)

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11
Q

What is ohm’s Law?

A

V= IR

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12
Q

What is index of refraction formula?

A

The index of refraction : speed of light in vacuum / the speed of light in the medium.

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13
Q

What is the intensity of electromagnetic radiation ?

A

intensity of electromagnetic radiation is defined as energy emitted per unit time.

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14
Q

What is the energy of electromagnetic radiation proportional to?

A

proportional to number of photons

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15
Q

What is THz when it comes to frequency ?

A

THz = 1 trillion hertz (1012 Hz) when measuring frequency

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16
Q

what formula can be used to calculate fraction of radioactive decay ?

A

1/2 ^n
n= number of half lives
first value after equation (how much if isotope is left)

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17
Q

What is the formula for volume flow rate ?

A

Q = Vt
Q= volume flow rate
V= volume
t= time

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18
Q

What is the formula for Power ? What is the unit for power ?

A

P = work/ time
unit : Watts (W)

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19
Q

What is the unit for Work ?

A

unit: Joules (J)

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20
Q

What kind of bonding enhances rigidity of a compound ?

A

INTERMOLECULAR bonding enhances rigidity of a compound

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21
Q

What is the difference between intramolecular and intermolecular bonding ?

A

Intermolecular : are the attractions between molecules
Intramolecular : forces WITHIN molecule that hold it together

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22
Q

What are the different intramolecular forces ?

A

intramolecular forces: covalent, ionic and metallic bonding

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23
Q

What are the different intermolecular forces ?

A

Intermolecular forces: ion-ion interactions, dipole-dipole, hydrogen bonding and london dispersion force

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24
Q

What kind of force is disulfide bridge?

A

intermolecular covalent bond

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25
Q

Which amino acid side chains can participate in electrostatic interactions ?

A

when one positively charged
amino acid is paired with one negatively charged amino acid
ex: Aspartic acid and arginine

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26
Q

Which amino acids are acidic ? What is their sign?

A

Aspartic acid and Glutamic acid (ch3ch2)

(negative charge )

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27
Q

which amino acids are polar neutral ?

A

Serine, threonine, asparagine, glutamine, cysteine and tyrosine

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28
Q

which amino acids are basic? What is their sign ?

A

Arginine, histidine and lysine
(postive charges)

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29
Q

which amino acid side chain has a primary alcohol ?

A

SERINE

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30
Q

What does the amino acid side chain of threonine have?

A

Threonine has a SECONDARY alcohol

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31
Q

What is important for pH dependence of aggregation ?

A

a compound side chains whose net CHARGE respond to pH

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32
Q

What is the relationship between velocity and cross sectional area ?

A

inverse relationship
as velocity decreases, cross sectional area increases (A1V1= A2V2)

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33
Q

What types of orbitals of central atom are octahedral?

A

Sp^3 d2

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34
Q

What are properties of ideal gases ?

A

-The Ideal Gas Law is PV = nRT
-Ideal gas is composed of particles that have negligible volume and do NOT exert intermolecular forces.
-The molar volume of an ideal gas at 25°C is 24.4 L

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35
Q

What is the formula for pH? What is relationship between pH and proton [ ] ?

A

pH = -log [H+]

the lower the pH, the higher the concentration of H+ (protons)

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36
Q

What does a difference of 3 pH units correspond to in proton concentration ?

A

pH scale is logarithmic (pH = –log([H+]).

** A difference of 3 pH units corresponds to a 10^3 = 1000-fold difference in proton concentrations.

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37
Q

What type of bonds are formed in glycogen ?

A

ALPHA 1, 4 glycosidic bonds

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38
Q

what are the structures contained in UDP-glucose ?

A

glucose, and RIBOSE

ribose, is a pentofuranose in which the C2 and C3 hydroxyl groups are cis, and the C3 hydroxyl group and the C4 hydroxymethyl group are trans.

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39
Q

Distinguish between the types of radioactive decay and their properties

A

Alpha decay : mass number decreases by 4 and atomic decreases by 2 (minimal penetration power)
Beta - decay : atomic number increases by 1 (gain 1 electron) ; mass number same (light penetration)
Beta + decay (POSITRON EMMISSION) : atomic number DECREASES by 1 ; mass number the same
gamma decay : Mass number and atomic numbers stay the SAME (Deep penetration power: Em radiation )

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40
Q

which type of bond partakes in branching in glycogen ?

A

ALPHA 1, 6 glycosidic bonds

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41
Q

What are the two major bonds that glycogen is composed of ?

A

alpha 1, 4 bonds (linear chain) and alpha 1, 6 bonds (branched)

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42
Q

What decreases acid dissociation ?

A

compounds with negative charges decreases acid dissociation (ex: h4Po4^2- )

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43
Q

What is the magnification formula ?

A

m = height of image/ height of object

(m = hi/ ho)

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44
Q

What type of decay emits photons ?

A

Gamma decay

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45
Q

what type of decay emits protons ?

A

Beta Plus decay

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46
Q

What type of decay emits electrons ?

A

Beta minus decay

47
Q

What leads to increase in entropy (positive delta S) ?

A

solid (or liquid) forms gases (increases disorder)

48
Q

What happens if a homogenous catalyst cannot be separated from product in reaction ?

A

Product will be CONTAMINATED

49
Q

What happens when you grind heterogenous catalysts?

A

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

50
Q

What is the position for anode and cathodes in an electric circuit ?

A

Left side of circuit: ANODE (oxidation)
Right side of circuit: Cathode (reduction )

(RED CAR
ANOX )

51
Q

What value must E be in electrochemistry for a spontaneous reaction

A

E must be POSITIVE for spontaneous reaction

52
Q

what is conversation of L to mL?

A

1 L converts to 10^3 mL

53
Q

What is equation for molarity ?

A

M = mol/ L (volume)

54
Q

What are the different units for Power ?

A

Watts (W)
J x second^-1 (Jx s)
ft x lb x s^-1
kg x mg x s^3

55
Q

What is formula for kcat?

A

V max = cat [Enzyme] total

56
Q

What happens if reaction is run at substrate saturation ?

A

reaction rate will be EQUAL To vmax

57
Q

How does tertiary structure appear ?

A

Tertiary structures is structure of a fully folded protein

58
Q

How are polar and non polar molecules separated based on a silica gel with benzene as eluting ?

A

The least polar compound will elute First since, it has weakest attraction to polar stationary phase. The last molecule to elute will be Most polar compound

58
Q

What is the relationship between energy of photons and wavlength? How does this impact excited state and ground state ?

A

E = hc/wavelength
hence if energy decreases, wavelength is longer .
. Thus, the excited state of the electrons in the compound will be CLOSER to the Ground state energy (if energy is lower, wavelength longer)

59
Q

What is the half life of radioactive material ?

A

The time it takes for half of all the radioactive nuclei in a sample to decay into their daughter nuclei.

59
Q

Which amino acid has abbreviation E

A

Glutamic acid (negatively charged)

60
Q

Why must the person in chair either lean forward or slide their feet under the chair in order to stand up ?

A

**To keep the body in equilibrium while rising ***
. [If the person doesn’t lean forward or slide their feet under the chair, they won’t have rotational equilibrium. So leaning forward puts their center of mass above the fulcrum, making the torque zero (because Torque=distance from fulcrum x force sin (theta), and in this case that distance would be zero).]

60
Q

Which amino acids has abbreviation D?

A

Aspartic acid (negative charge)

61
Q
A
61
Q

which amino acids has abbreviation Q?

A

Glutamine

62
Q

Which phosphate is usually transferred in ATP by kinase ?

A

THe LAST phosphate in ATP is usually transferred by kinase.
Hence 3 phosphates will be transferred in order (alpha, then beta and lastly gamma) hence kinase will transfer gamma Phosphate

63
Q

What kind of curve indicates cooperativity

A

SIGMOIDAL shape

64
Q

what is melting temperature ?

A

Melting temperature: the temperature at which 50% of DNA molecules and solution are Denatured

65
Q

What does a high melting temperature indicate ?

A

higher melting temperature is indicative of a MORE STABLE protein, as more energy is needed to unfold the protein.

66
Q

What phenomenon causes static air to be drawn into the mask when oxygen flows

A

VENTURI effect:

( Venturi effect: reduction in fluid pressure when a fluid flows through a constricted section)

67
Q

How do GC and AT base pairs differ? How does this affect their melting temperature ?

A

GC bonds have 3 hydrogen bonds while AT bonds have 2 hydrogen bonds
hence GC bonds are stronger and more stable, hence they will have HIGHER melting temperature than AT base pairs and stronger pi stacking interactions

68
Q

What is the relationship between vapor pressure and boiling point?

A

INVERSE RELATIONSHIP
One with Low boiling point will have HIGHER Vapor pressure at the same temperature

(kinetic molecular theory of gases)

69
Q

What is structure for storage lipids ?

A

Storage lipids are Triacylglycerols which are three fatty acids ester linked to a glycerol

70
Q

What is Le Charlier’s principle ?

A

According to Le Chatelier’s principle, removing a product in an equilibrium reaction will cause the system to restore equilibrium.

71
Q

What is role of catalyst ?

A

A catalyst lowers the activation energy for a chemical reaction, thus increasing the reaction rate (amount of ammonia produced per unit time).

72
Q

What is the equation that includes G not and K (formation constant) ? Describe the relationship between variables.

A

Delta G not= - R T lnK
if K > 1, delta G not will be < 0

(when delta G < 0 , reaction is spontaneous)

73
Q

What happens when HCL is added to ammonia ?

A

HCL will protonate ammonia (NH3) leading to NH4 (ammonium)

(if this occurred in a reaction it could affect equilibrium)

74
Q

What can products can be deprotonated by NAOH in extraction ?

A

In extraction, NAOH can deprotonate phenols and carboxylic acids

75
Q

What can NaNH2 deprotonate in extraction ?

A

In Extraction, NaNH2 can only deprotonate CARBOXYLIC ACIDS

76
Q

What is the coordination number ?

A

the number of co-ordination bonds with which the ligands are bound to central ion
ex: ([Cu(NH3)4]2+)
4 is coordination number for Cu^2+

77
Q

What determines if one molecule is a stronger lewis base than another molecule ? What does this indicate ?

A

A stronger lewis base will have an atom that is LESS Electronegative than atom in other molecule.

ex: NH3 is a stronger Lewis base than H2O because the nitrogen atom is less electronegative than the oxygen atom.
This results in the oxygen atom having a stronger attraction for its lone pairs of electrons, making them less available for donation and H2O less Lewis basic than NH3.

78
Q

What is second ionization energy ?

A

Second ionization energy: is the minimum energy required to remove a second electron from a positively charged ion: X+(g) → X2+(g) + e–

79
Q

What is the electron configuration for Calcium ? What happens when you remove 2 electrons from calcium ?

A

Calcium, has an electron configuration of 1s2 2s2 2p6 3s2 3p6 4s2.
Losing two electrons from calcium will lead to a stable noble gas conjuration (1s2 2s2 2p6 3s2 3p6) with a full octet.
Hence it will require LOWEST energy since it forms stable config

80
Q

What is the Henderson Hasslebach equation ?

A

pH= pka + log ([base]/[acid])

(remember that log(1) = 0

81
Q

What is the dissolution for compound CaCO3? How do you determine the concentration of Calcium in structure with Ksp value of 4.9 x 10^-9 ?

A

The dissolution of CaCO3 is CaCO3(s) ⇌ Ca2+(aq) + CO32–(aq) and the solubility product constant expression is Ksp = [Ca2+] [CO32–] .
Since Equal amounts of Ca2+ and CO32– are produced when CaCO3 dissolves in solution, so the expression reduces to x^2 = 4.9 × 10–9, which is equal to 49 × 10–10.
Taking the square root, x = 7.0 × 10–5 M.
hence concentration of calcium is 7.0 x 10^-5

82
Q

What is systolic blood pressure ?

A

systolic blood pressure: the pressure exerted on the blood vessel walls when the heart is contracting

83
Q

when will blood flow be heard if blood pressure reads 130/85 ? What is systole and what is diastole?

A

blood pressure 130/85
systole : 130
diastole: 85
Blood flow will be heard if the blood pressure during systole is GREATER than the pressure in the cuff.

84
Q

What dictates the direction that a particle will move for magnetic fields ?

A

charge.
like charges repel each other (move away from each other) and opposite charges attract (pull towards each other )

85
Q

What is the electronic charge value ?

A

E= 1.6 x 10^-19 C

(C = coulomb)

86
Q

What is the equation for charge of system ? What is the difference between excess and being deficient in charges ?

A

The charge of system = electronic charge x number of electrons

If an object is positively charged, it is electron deficient.
If an object is negatively charged, it has an excess of electrons

87
Q

What is the relationship between bond energy and bond strength ? Length?

A

The strength of a bond is DIRECTLY proportional to its bond energy
STRONGER bonds have LARGER bond energies
Shorter bonds are Stronger than longer bonds

88
Q

What is Hess’s Law?

A

Hess’s Law, (the sum of ΔH°f products) – (the sum of ΔH°f reactants).

89
Q

If the magnitude of ΔH° (in kJ) for the decomposition of 2 moles of nitroglycerin at 25°C is closest to which of the following?

A

passage question
he value of ΔH° can be calculated using the data provided in Table 1 using Hess’s Law, (the sum of ΔH°f products) – (the sum of ΔH°f reactants).
The amount of nitroglycerin (in kJ) decomposed is calculated by: [12(–393.5) + 10(–241.8)] – [4(–364.0)] however if asking for 2 moles of nitroglycerin when originally had 4 moles divide by 2 for all moles in reaction . Hence 6 (400) + 5 (2400) - 4 (4000) = approx 2700 which is close to 3000

90
Q

What is the molar volume of ideal gas at STP ?

A

molar volume of an ideal gas at STP is 22. 4 L

91
Q

What equations can be used for power ? Units?

A

Power = work / time
Power = change in PE/ time (P= mass x gravitational acceleration (10) x height /time
units: Watts or J/s or Nm/s (kg x m2 x s^-3)

92
Q

What is the elastic potential energy equation ?

A

U = 1/2 k x^2

x = displacement
k= spring constant
U = elastic PE

93
Q

What is the ratio of sound intensities heard by male (20 dB) and female (40 db)

A

The relative intensities of the two sound waves are 20 dB and 40 dB, respectively. Their difference (40 -20) is 20 dB, meaning that the decimal log of the ratio of their intensities is 2, which means that the ratio of their intensities is 10^2 = 100.

94
Q

What is the decibel formula for sound intensity ? What is a short way to calc ratio of sound intensities ?

A

dB= 10 log (I/Io)

Short hand way: think of decibels is the number before the zero (i.e. 2 in 20) is how many “zeroes” there are to measure intensity. For example, 20 decibels = 2 zeros = 100 (10^2). 30 decibels = 3 zeroes = 1000 (10^3).

95
Q

What are properties of diverging lens ?

A

Diverging lens :
Diminished (REDUCED)
UPRIGHT
Virtual

(D DUV)

96
Q

What are properties of converging lens ?

A

Converging lens are :
ENLARGED
inVERTED
REAL

(CIRE)

97
Q

What is the sign of object distance for all mirrors and lenses ?

A

The Object distance (do) is ALWAYS POSITI VE

98
Q

compare and contrast concave and convex mirrors ?

A

Concave : focal length is POSITIVE
Convex: focal length is NEGATIVE

99
Q

for mirrors , how do you distinguish images ?

A

for mirrors
-If image and object are on the OPPOSITE sites (aka mirror is in the middle of the two), image distance (di) is NEGATIVE.

-If image and object are on the SAME site (aka mirror is not in the middle of the two), image distance (di) is POSITIVE.

100
Q

How do you differentiate between images for lens ?

A

For lens (opposite way compared to mirrors)
Lens:
-If image and object are on the OPPOSITE sites (aka lens is in the middle of the two), image distance (di) is POSITIVE.

-If image and object are on the SAME site (aka lens is not in the middle of the two), image distance (di) is NEGATIVE.

101
Q

What is the formula for magnification ? How does image change with magnification ?

A

M=(-di)/(do)

-When M is positive, your image maintains its original orientation.

-When M is negative, your image is inverted.

102
Q

What are the properties of Convex mirror ? Why is this significant ?

A

Convex mirrors are Diminished (REDUCED) Virtual, Upright
significant because it has properties of diverging lens (DUV)

103
Q

What is the approximate percentage of a 10C sample left after the time it took a 75-year-old male to walk one lap around the gym? (Note: The half-life of 10C is 20 seconds.) and average 75 yearly male walks 5 laps in 200 seconds.

A

it took an average 75 y/o male to walk 5 laps in 200s. Therefore, an average lap time of 200s/5laps = 40 s/lap. The half-life of C10 was given as 20s. Therefore, Start from there:

In 20s, C10 goes from 100% –> 50%. This is half of the full lap.
In the next 20s (total of 40s), C10 goes from 50% –> 25%. This is the full lap, and thus, the total amount of C10 remaining after the lap.

104
Q

Which of the following energy conversions best describes what takes place in a battery-powered resistive circuit when the current is flowing?

A

Chemical–> electrical —> Thermal energy ?

105
Q

What bonds are present in secondary protein structures/

A

Secondary structure: includes turns, helices, and beta sheets, all of which are established by hydrogen bonds between **backbone amide protons and carbonyl oxygen **

106
Q

What is the formula for resistors in parallel ? If a 60-Ω resistor is connected in parallel with a 20-Ω resistor. What is the equivalent resistance of the combination?

A

Resistors in parallel : 1/req = 1/ R1 + 1R2 + 1/R ……

To get Req by itself you have to do 1/ (1/req)
hence 1/ 1/20 + 1/60 = 1/ 1/15 = 15 ohm

107
Q

What is the formula used to determine if a compound is acidic or basic ?

A

Ka x Kb = Kw
if ka > kb : compound more ACIDIC
if kb > ka : compound is Basic

108
Q

What is the limiting reagent ? How do you calculate it? Example ?

A

Limiting reagent: compound that will be used up after experiment
Ex: According to the passage, the ratio of moles of iodine atoms to zinc atoms is 2:1. if there are 2g of iodine and its molar mass is 127 g/mol (for I^2) you find mole for iodine. If there are 2 g of zinc you find mol by dividing 2g Zn /molar mass zinc and find mole. Then compare moles of zinc and iodine and see which one has smaller value and hence will be used up first (limiting reagent)

109
Q

What happens to variables if energy is maximized ?

A

E = hf or c = wavelength x frequency
hence if you maximize Energy you maximize frequency and minimize wavelength

110
Q

what happens to electrical field lines if an electrical field is uniform between electrodes ?

A

The electric field lines will be EQUALLY SPACED

AAMC Material (3 decks)

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