Chem/Phys Equations and Techniques Flashcards
Translational motion
∆x = vot + 1/2at2
(Vƒ)2 = (Vo)2 + 2ad
Vƒ = Vo + at
Frictional force
fmax = μ Ν
- N= normal force
- u= coefficient of friction
μk < μs always
Uniform circular motion
Fc = mac = mv2 /r
ac= v2 /r
Momentum, Impulse
I = F Δt = ΔM
- applied force x time
M = mv
- mass x velocity
Impulse is the change of momentum of an object when the object is acted upon by a force for an interval of time. So, with impulse, you can calculate the change in momentum, or you can use impulse to calculate the average impact force of a collision. A longer collision or impact time translates to a smaller force.
Work
W = F d cosθ
W = ∆KE
W = -P∆V
Joules
Energy (conservation)
ET = Ek + Ep
Spring Force, Work
F = -kx
W = kx2 /2
Current, Resistivity, Resistance
I = Q/t
- Current = quantity of charge / time
R = ρL/A
- resistivity = p (resistivity of wire) x Length of wire / cross sectional area of wire
V = IR
- Voltage = current x resistance
Resistors (series)
Req = R1 + R2 . . .
Resistors (parallel)
1/ Rtot = 1/ R1 + 1/ R2
Capacitors in Ser.
1/ Ceq = 1/ C1 + 1/ C2 + 1/ C3
Capacitors in parallel
Ceq = C1 + C2 . .
Sound
dB = 10 log10 (I/I0)
- I = intensity
- Io = minimum threshold of human hearing
beats = Δ ƒ
Thermodynamics and changing phases
Q = mc Δ T (MCAT)
- c= specific heat
- The specific heat is the amount of heat necessary to change the temperature of 1.00 kg of mass by 1.00ºC.
Q = mL
- m= mass
- L = specific latent heat
- the amount of energy required to change the state of 1 kilogram (kg) of a material without changing its temperature. … latent heat of vaporisation - the amount of energy needed to boil or condense the material at its boiling point.
Coulomb’s Law:
F = k∙(q1q2/r2)
This law quantifies the force between two electrically charges particles. The electrical force (F) of repulsion or attraction between the particles is proportional to the product of the charges (q) and is inversely proportional to the square of the distance between them (r2). In this equation, k is Coulomb’s constant.
Kinetic and potential energy
Ek = 1/2 mv2
Ep = mgh
Ρressure
Pressure under water
P = F/A
ΔΡ = ρgΔh
p = fluid density
Specific Gravity
SG = ρ substance / ρ water (relative density)
ρ of water= 1 g/cm3 = 103 kg/m3
Density
Buoyant force
ρ = mass / volume
Fb = ρgV
- density of the fluid, gravity, volume of the object
If an object has a specific gravity of .92 (like ice), 92% of the object will be submerged in water
Optics power and magnification, total magnification
Power = 1/ i + 1/ o = 1/ f = 2/r
- f = focal length
- the power of a converging lens is positive and that of the diverging lens is negative.
M = magnification = - i/o
- image/object
mtotal= m1 x m2….
Gibbs Free Energy (standard and nonstandard)
Gas constant R=
ΔG = ΔH - TΔS
- if H is positive and S is negative, ∆G always positive
- if H is negative and S is positive, ∆G always negative (spontaneous)
ΔG° = -RTln Keq
- R = 8.3145 J/(mol x K)
Dopplers effect
Higher frequency when coming towards you, lower when going away
fo = observed
v = speed of sound waves
vo = observer velocity
vs = source velocity
fs = actual frequency of sound waves
Bernouilli’s Equation
Bernoulli’s principle: Within a horizontal flow of fluid, points of higher fluid speed will have less pressure than points of slower fluid speed.
P1+ 1/2ρv12 + ρgh1 = P2 + 1/2ρv22 + ρgh2
This equation allows you to analyze a fluid as it moves through a tube and relates the velocity of the fluid to its pressure. For a horizontal tube that changes in diameter, regions where the fluid is moving fast will be under less pressure than regions where the fluid is moving slow. Bernoulli’s equation applies principles of energy conservation to a flowing fluid. In this equation, P is the hydrostatic pressure, ρ is the density of the liquid, v is the velocity, g is gravitational acceleration (9.8 m/s2), and h is the height of the liquid in meters.
parallel plate capacitor equation
Electric field equation
C = ε(A/d)
E = V/d
Voltage = electric field x displacement
Capacitor work
W = 1/2 CV2
- capactitance
- V = potential difference, voltage
Physics math
Radians to degrees
root 3, root 2
area of circle, circumference
Angle θ may be given in radians (R) where 1 revolution = 2πR = 360°
Estimate square root 3 as 1.7 and root 2 as 1.4
Cross-sectional area of a tube = area of a circle = πr2 where π can be estimated as 3.14 and r is the radius of the circle; circumference = 2πr
Units to memorize
Both work and energy are measured in joules where 1 joule (J) = 1 N × 1 m . {Imperial units: the foot-pound , CGS units: the dyne-centimeter or erg }
The SI unit for power is the watt (W) which equals one joule per second (J/s) = volts × amperes.
Current is measured in amperes = coulombs/sec. The units of resistance are ohms, symbolized by Ω (omega), where 1 ohm = 1 volt/ampere.
The SI unit for pressure is the pascal (1 Pa = 1 N/m2 ). Other units are: 1.00 atm = 1.01 × 105 Pa = 1.01 bar = 760 mmHg = 760 torr.
The SI unit for the magnetic induction vector B is the tesla where 1 T = 1 N/(A)(m) = 104 gauss.
Boyle’s Law:
Pressure and volume
PV = constant,
P1V1 = P2V2
Avogadro’s Law:
V1/n1 = V2/n2
Dalton’s Law of Partial Pressures:
PTotal = P1 + P2 …
Photon Energy:
Planck’s constant
E = hf
E= hc/ λ
Planck’s constant = 6.62607015 × 10−34
Snell’s Law:
n1sinθ1 = n2sinθ2
Snell’s Law describes the change in direction of a light ray as it moves from a medium with one refractive index (n1) to another medium with a different refractive index (n2). The angle (sinθ1) of incidence towards the surface and the angle (sinθ2) of refraction are measured relative to a surface normal.
Lens Equation:
1/f = 1/o + 1/i
for a convex lens the focal length will always be positive
for a concave lens the focal length will always be negative.
Van der Waals equation (real gases)
What do a and b mean?
P = RT/(V-b) - a/V2
V = molar volume
The a and b are called van der Waals constants: The constant a provides a measure of the average attraction of the molecules, whereas constant b adjusts for the volume occupied by the gas particles
Graham’s rate of effusion of gases
Quantum numbers
Electronic configuration rules
Solutions equations
molarity
molality
mole fraction
mass percent
ppm
Freezing point depression
m = molality = moles solute/ kg solvent
k = constant
Boiling point elevation
Osmotic pressure
πV = nRT
Phase diagram for water
It has a negative slope due to the fact that when ice melt, the molar volume decreases. Ice actually melt at lower temperature at higher pressure.
Large Keq
Indicate reaction has almost gone to completion
Buffer solution equation
(for pOH)
pOH = pKb + log [HB]/[[B]
pH equations
pH = -log[H+] pOH = -log[OH]
pKa = -log[Ka] pKb = -log[Kb]
pH + pOH = 14 pKa + pKb = 14
Ka x Kb = Kw = [OH][H+] = 10-14 (at 298K)
1st law of thermodynamics
Conservation of energy: energy can neither be created nor destroyed, only transformed or moved
In Closed Systems:
∆U = Q - W
change in internal energy = heat transfer into system - work performed by the system
if system performs work, loses energy to environment
positive value if work is done on the system
Doesn’t apply in open systems
Standard temp and pressure vs standard conditions
Arrhenius acid and base
Lewis acid and base
Bronsted Lowry acid and base
Rate determining step
Slowest elementary step in reaction
First step is rate determining
Pascal’s Law
Force and area
F1/A1 = F2/A2
Molar heat of solution, vaporization, fusion
Total entropy change
+ entropy change is increase in disorder
All spontaneous change occurs with an increase in entropy of the universe. The sum of the entropy change for the system and the surrounding must be positive(+) for a spontaneous process.
Cell potential
key difference between electrode potential and cell potential is that electrode potential refers to the ability of an electrode in a cell to get reduced or oxidized whereas cell potential is the difference between the electrode potentials of the electrodes present in an electrochemical cell.
Anode
Electrode where oxidation occurs, half reaction with more negative reduction potential
Cathode
Electrode where reduction occurs, more positive half reaction reduction potential
Le Chateliers Principle
Pressure
Pressure of a liquid
F/A
density x mass x height
Linear and volumetric expansion
Center of mass
1 Joule =
N x m
Torque
When to use Joules, Watts, Newtons
Newtons is force
Joules is work (N x m), kinetic and potential energy
Power is watts (J/s)
Frequency of a wave
Speed of a wave (not in a vacuum)
Speed of light is in a vacuum
F = 1/T (Hz)
- Period (T) is number of seconds per cycle; inverse of frequency
v = wavelength x frequency
c = fλ
Magnetic Force
F = qvBsin0
Acid and base dissociation constants
PRODUCTS OVER REACTANTS (excluding water)
Michaelis-Mentin
Km
Vmax
Equation
Km is the concentration of substrate which permits the enzyme to achieve half Vmax. An enzyme with a high Km has a low affinity for its substrate, and requires a greater concentration of substrate to achieve Vmax.
Vmax is the maximum rate that can be observed in the reaction
Capacitance
energy of a capacitor
C= q/V
- charge over voltage
C = εA/d
- area of plates over length
E = 1/2 * C * V² (also work eq)
Power
P = W/t
P = Fv
P = I2R
Watts = J/s
Concave vs. Convex lens focal point (+/-)
Focal point is positive for convex lens, negative for concave lens
Absorbance
Focal point =
r/2
Vapor Pressure equation
If a liquid is exposed to air, some will evaporate into a gas until gas and liquid phases reach equilibrium; increases with temp
- pressure exerted by gas above liquid is vapor pressure
- Adding solute to liquid reduces amount of gas produced
- attraction between solvent and solute particles
- surface composed of solvent and solute, less surface area for solvent to evaporate
- solutes must be nonvolatile (don’t evaporate readily)
P = XaPa
Vapor pressure in soln = mole fraction x vapor pressure of pure solvent
Mechanical advantage
Using a mechanical apparatus to perform work using less force
- inclined plane, pulley, seesaw
for ramps, incline length /incline height gives the amount of force increased by just going vertically
Winput = Woutput
- Increasing distance decreases force put in, increases force put out
**Levers can have a mechanical advantage less than one, inclined planes cannot
Harmonics
1st harmonic: Standing wave on a string with only one antinode is lowest frequency
wavelength is twice the length of string (1 wavelength is two antinodes)
2nd harmonic: two antinodes, wavelength = length of string
3rd harmonic: 3 antinodes, 1.5 wavelengths
- λ = 2L / N
**antinode is at peaks
Competitive inhibition
Binds to enzyme active site, inhibits binding of substrate (“competes with substrate”)
Increases Km (amount of substrate needed to reach Vmax)
No change on Vmax
Uncompetitive inhibition
Binds at enzyme substrate complex, inhibits binding of substrate
Decreases Km
Decreases Vmax
Mixed competitive
Binds at enzyme substrate complex or just enzyme
Increase or decrease Km
Decrease Vmax
Noncompetitive inhibitor
Binds at ES complex or enzyme
Doesn’t inhibit binding of substrate, “noncompetitive”
No change for Km
Decrease Vmax
Pressure units
The SI unit for pressure is the pascal (1 Pa = 1 N/m2 ). Other units are:
1.00 atm = 1.01 × 105 Pa = 1.01 bar = 760 mmHg = 760 torr.
Percent yield
Percent Error
Actual/theoretical x 100
Actual -Theoretical /Theoretical x 100
Ksp
is the equilibrium constant for a solid substance dissolving in an aqueous solution.
mass
quantitative measure of inertia, a fundamental property of all matter. It is, in effect, the resistance that a body of matter offers to a change in its speed or position upon the application of a force
weight = mg
m = density x volume
F = ma
Ideal gas kinetic energy equation
KEparticle = 1/2 mparticle vrms2
root mean square velocity = √ 3RT / Mm
R = Ideal gas constant
Mm = molar mass
T = temp (kelvin)
Temp and KE related
Neutralization
When an acid is neutralized, all of the protons from the original acid have reacted with hyroxide ions from added base
- ratio of acid to base is 1:1 in moles
- Monoprotic acid contains only one acidic proton
- Monoprotic base can only accept one proton
MaVa = MbVb —> for monoprotic acids
Molarity and volume of acid and base
For diprotic and triprotic acids, have to use normality (moles solute/kg/solvent)
Enthalpy, entropy, and temperature
∆G = ∆H - T∆S
Recrystallization
- Solid product placed in liquid solvent and heated to dissolve
- Mixture cooled again and solid allowed to reform
* typically excludes many impurities present before
Ideal solvent is one in which desired product is soluble at high temperature, relatively insoluble in low temp (methanol)
Often repeated many times over
Heating Curve
For heating curves, temp increases until reaches value the bonds become broken and thats where phase change occurs
∆Hf = enthalpy of fusion =
-
how much heat is needed to melt one mole of substance (kJ/mol) = Q/m (kJ/kg)
- 334 kJ/kg for water (energy required to melt 1 kg of ice)
∆Hvap= enthalpy of vaporization=
If we’re melting a block of ice into gas, have to conside q=mc∆T + n∆Hvap + n∆Hf
- **Phase change: n comes from grams of original substance times mol/g
- multiply this by ∆Hfusion/∆Hvap
Standard Reduction Potential - half reactions
- Tendencies for atoms to be reduced in any redox reduction half reaction (E°)
- measured in volts, relative to each other
the more positive an E° is, the more spontaneous the reduction
the more negative, the more nonspontaneous the reduction
- **Any half reaction can be reversed to form the oxidation half rxn, reaction that is more spontaneous ISN’T reversed
- also reverse sign of E°
add two potentials for standard potential of full rxn
*Don’t need to balance eqn, not affected by stoichiometric constants
Enantiomeric excess
ee = observed opitcal rotation/specific optical rotation x 100
Mass Spectroscopy
How to determine molecular mass?
Uses magnetism to determine mass
- First step is ionization using an electron beam
- creates ions and can break apart molecules
parent ion: ion created by loss of just one electron and no fragmentation (M+)
- maintains parent molecular weight but is charged
Accelerate into magnetic field and uses Fb = Bqvsin0 to determine the angle of deflection
- separated by mass to charge ratio
- y axis is relative abundance, x axis is m/z
*** M+ is the peak furthest to the right and thats how you determine the molecular mass
Pouiselles Law (don’t need to know equation, just implication)
For flow through pipes
Venturi Effect
Flow rate = ∆pressuredrop x radius / length
large pressure drop causes flow rate to increase
increasing radius dramatically increases flow rate
increase in length of tubing decreases flow rate
***FLOW RATE IS VOLUME of water
Venturi Effect: The narrower the tube, the lower the pressure
Nonconservative forces
Dissipate energy, path dependent
- friction, air resistance, viscosity
F = mg
Gm1m2 / r2
Gravitational force between two masses
Gravitational force between two masses
Gm1m2 / r2
r = distance between them
Amphoteric
Can either accept or donate a proton (acid and base)
water, amino acids
If you are experimenting with an acid-base equilibrium reaction,
the keq value is Ka, also known as acidity constant, which measures the strength of an acid in solution
Projectile Motion
Only force acting on object is gravity; no horizontal acceleration, force stopped acting on object when enters arc
- Movment in x and y direction function independently
- **Time is connector between x and y components
- Projectile has some initial vertical velocity
vx = vicosθ dx = vxt
vy = visinθ + gt vy = 0 at top of curve
then use kinematic eqns vf2 = vi2 + 2ady
vf = vi + at
∆d = vit + .5at2
calorie
The amount of energy required to raise the temp of 1 gram of water by 1 deg C
Chromatography
In all chromatography, two phases:
Mobile phase: moving fluid or gas
Stationary phase: immobile substance that retains some molecules moving through the mobile phase
Solutes travelling at different speeds based on affinity for mobile and stationary phases
-log[A x 10-B] =
B - 0.A
Electric force vs. magnetic force equation
Magnetic Fb = qvBsin0
Electric F= -k Q1Q2 / d2 , ends up being F = kq/d2
- COULOMBS LAW
- negative cancels with negative charge
Uniform Electric Field and Work done by electric current
F=Eq
W = q∆V
Units and prefixes
Proportional symbol
∝
What properties of waves is unaffected by passing through a new medium
Frequency
Flow rate
Q = vA
v = velocity
A = area ( look for units2)
Ksp
Ksp = [A+]a[B-]b
A= cation
B = anion
If reaction is spontaneous, what is Keq value
ΔG = –RTln(Keq)
Keq is > 1
Inclined planes
Extraction (separation technique)
Can you separate two different acids using extraction?
Takes advantage of two liquid phases: polar aqueous phase (usually water) and relatively nonpolar organic phase (organic solvent, immiscible with water (don’t mix))
liquid half in separatory funnel, denser liquid at the bottom
Like dissolves like, shaking the funnel separates them into polar and nonpolar solutes
- **If compound is uncharged and has both polar and nonpolar groups, non polar groups win
- by using acid base properties, you can add protons to create polarity
Can separate two different acids if they have very different pKa’s
Simple Distillation (for very different boiling points) vs Fractional
Separates liquid by their boiling point using votality and vapor pressure
- vapor pressure: pressure exerted by liquid molecules
- Round bottom flask with mixture is heated
- Liquid becomes gas and rises up to a condensor
- Cold water around condensor changes gas back to liquid
Doesn’t always separate perfectly –> REPEAT DISTILLATIONS
Fractional:
Uses fractional distillation to separate liquids with close boiling points
1. Increases vertical distance that vapor travels
- Allows vapor to recondense and revaporize repeatedly
Thin Layer Chromatography
Retention Factor
Can be used to detect impurities in a sample
Stationary phase: glass or plastic plate coated with a thin layer of absorbent material like silica gel (HIGHLY POLAR)
Mobile phase: nonpolar solvent such as hexane, referred to as “eluent”
- Spots are placed at bottom of stationary phase plate and just above mobile phase solvent
2. Capillary action pulls mobile phase up the plate, compounds in the sample will also travel upward
Nonpolar particles travel further than polar (have higher affinity for plate and don’t want to move)
Allows us to make rough measurements of polarity of compounds using Retention Factor (Rf) = distance travelled by compound/distance travelled by solvent
- nonpolar compounds have higher Rf typically
Column Chromatography
1. size exclusion: separate components based on physical size
- stationary phase has pore studded beads, larger molecules pass through faster (OPPOSITE of what we’d think)
2. cation exchange: traps positive molecules, negatively charged stationary phase
3. anion exchange: opposite
-
affinity: ligands designed to bind to molecule of interest are attached to stationary phase
* once solution has passed through, dissociate bound compound of interest
5. gas-liquid: gas mobile phase and sample, liquid is stationary phase
- time spent in compound depends on volatility and affinity
- smaller compounds have earlier peaks when analyzed
To begin crystallization and recrystallization, requires initial…
Nucleation
Nucleus or tiny seed crystal initiates crystallization
Scratch side of glass
Spectroscopy
Infrared spectroscopy
Analysis of molecules based on interaction with electromagnetic radiation
IR:
Uses infrared radiation and molecule interactions ***different bonds have distinct ways of interacting with IR radiation
** must be a dipole present, usually polar covalent bonds
vibrational frequencies: even those with dipole present, requires specific frequency of IR radiation to stretch or bend
x-axis: different wavelengths of IR radiation
y-axis: transmittance (low transmittance means high absorption)
For IR spectroscopy, double bonds with carbon appear at ____
****Carbonyl
Triple bonds are at ___
***O-H bonds are at ___
N-H bonds ____
Low frequency (below 2000)
*** Carbonyl at 1650, SHARP PEAK
Medium frequency (low 2000s)
3100-3500 BROAD AND WIDE
3300-3500
Absorption
UV/Vis spectroscopy
Colored compounds absorb some wavelengths of light and reflect others; we perceive an object to have color of the wavelength it reflects
UV/Vis spectroscopy is basically identifying compounds based on their color
Nuclear Magnetic Resonance (NMR) spectroscopy
Number of peaks for HNMR =?
Characterizing a molecules atoms (unlike IR which characterizes bonds) by how they interact with magnetic field
- either spin with field at lower energy or against it
1HNMR and 13CNMR
upfield: to the right, shielding
downfield: to the left, deshielding
Location on graph depends on shielding and deshielding of nucleus; carboxylic acids and electronegative atoms are deshielding and to the left on graph
- use n+1 for number of hydrogens on carbons adjacent to the target carbon
- this equates to its number of peaks on graph
Gel electrophoresis
Which way days DNA migrate
Charged macromolecules like DNA or protein are suspended in agarose gel and migrate due to application of electric current (like electrolytic cells)
Separates by size or charge
- Cathode: negative charge
- Anode: positive charge
DNA negative phosphate groups move towards anode
***Can isolate to just size by negating charge of proteins using SDS (anionic detergent) which UNFOLDS and makes neutral charge
- requires reducing agent to fully denature quaternary/tertiary structure
Hybridization lab technique
ssDNA or RNA to bond with cDNA or cRNA
Used to anneal DNA strands and artificially replicate DNA
Polymerase Chain Reaction
Repeated cycles of DNA sequencing that doubles them each time
Can also amplify RNA if it is reverse transcribed
Primers specific to target sequence
- Reaction heated to 95 deg C to denature two strands of DNA
- Cooled to allow primers to anneal to template strands
- Heated again to initiate synthesis by DNA polymerase = Taq polymerase
Heating and cooling done by thermocyclers
Protein purification
- Extract by lysing cellular membranes either by freezing and thawing, solvents, detergents
- often treated with protease inhibitors to keep lysed proteins from degrading other cells
- cooled and pH maintained
- Separation by centrifugation
- pellet: heavy dense particles
- supernatant: proteins usually stay in solution
- or by solubility: changing salt concentrations of surroundings
- Use chromatography to isolate desired protein
Temperature and Resistance
Temp and resistance increase linearly
Best primers of PCR
Best primers for PCR have a high GC content and CG bases in 5′ and 3′
Red litmus paper
Red litmus paper is a base indicator. It turns blue at 8.1 pH and higher. While not a measure of pH levels, it’s a quick and accurate way to determine if a solution is alkaline
Transition metals and color
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.
The energy of electromagnetic radiation is directly proportional to
the number of photons, and the intensity of electromagnetic radiation is defined as energy emitted per unit time. Thus, intensity is directly proportional to the number of photons emitted
Free fall problems
vi = 0
a = g
d = y
d = vit + 1/2gt2 or vf2 = vi2 + 2gy
Maillard Reaction
Gives food its distinctive brown color when burned; occurs between 140 and 160 deg C
- Amino acids in foods react with certain carbohydrates
- happens faster under basic conditions, amino groups deprotonated
At very high temps, carcinogen acrylamide can form if the food is charged
Reducing sugars act as reducing agents with amino acids
- All monosaccharides
any sugar with free aldehyde and non-aldose sugars that can be converted to an aldose (fructose)
- due to keto-enol tautamerism
- disaccharides and polysaccharides with free anomeric carbons
Cu2+, Ag+, Fe3+ detect reducing sugar presence in reactions
Tollen’s Test (reaction?)
Benedicts Test (reaction?)
Both test for ____
Testing for reducing sugars; Diagnosis of diabetes; diabetics have abnormally high blood glucose from not producing enough insulin or cells not responding to it
- excess glucose ends up in urine
Tollen’s Test: Silver ions used to oxidize an aldose (reducing sugar) which produces solid silver
Benedicts Test: Similar reaction with Cu2+ instead; begins with bright blue color and turns into red
ELISA
Utilizes carefully picked antibodies to detect a substance of interest
Refraction
If wave travels from one medium into another
- changes speed of waves and bends the light
- Light only refracts when it hits medium at an angle
- Dispersal of light: light with a longer wavelength (like red light) doesn’t change speed or bend as much as that with a shorter wavelength when passing into a new medium
n = c / v
- c = speed of light in a vacuum
- v = light speed in medium
- n is always greater than 1; nair is pretty much 1
Formal charge
Valence electrons of atom - bonds - nonbonded electrons
Redox reactions are usually
Single displacement - free elements have oxidation state of 0, can change when bonded in a compound
Combustion- hydrocarbon + oxygen = CO2 + water
Combination- A + B –> AB
Nuclear fusion
Two or more nuclei are forced together by extremely high levels of energy(like the sun), causing them to merge into new larger nucleus
- releases a lot of energy due to dissipation of binding energy of larger nucleus
produces a neutron
Nuclear fission
Large nucleus split into 2 or more nuclei
no nuclear particles lost
Photoelectric effect
Light shone on a metal surface causes electrons to be emitted from the metal
- Ekinetic = hf - Φ
net energy, the energy of the emitted photon minus the energy needed to remove the electron.
Absolute pressure
Pressure of a liquid on an object as well as atmospheric pressure above it
Pabsolute = Patmospheric + Phydrostatic
*atmospheric pressure is higher at lower altitude
Surface tension
**at the interface between air and water at the surface, the water molecules forces act unevenly on the ones at the surface and has no interactions with the air molecules
- this imbalance of forces creates tension
Surface tension = Force / Length (N/m)
Cohesion forces
Adhesion forces
Meniscus
Effect of intermolecular forces within a given substance causing them to stick together
Adhesion forces are molecules sticking to another type of molecule
- if adhesive forces are stronger than surface tension forces, liquid will crawl up walls of container and surface is curved (concave)(meniscus)
if fluid acts more strongly with itself than walls of container, has a convex shape
Laminar Flow vs Turbulent Flow
Laminar Flow: flowing fluid composed of parallel layers that may be moving at different velocities
Turbulent flow: flowing fluid composed of mixed layers that vary in pressure and speed
- the higher the velocity, the more likely the flow is to become turbulent
Harmonics of strings
1st harmonic: Standing wave on a string with only one antinode is lowest frequency
- wavelength is twice the length of string (1 wavelength is two antinodes)
2nd harmonic: two antinodes, wavelength = length of string
3rd harmonic: 3 antinodes, 1.5 wavelengths
λ = 2L / N
- for 3rd harmonic, N= 3
- L = length of string
Mass defect
Mass defect is the difference between the predicted mass and the actual mass of an atom’s nucleus. The binding energy of a system can appear as extra mass, which accounts for this difference.
Electron donating groups
Groups with electron pairs to donate
The oxygen anion, -O-
Alcohol groups, -OH
Amine groups, -NH2 or -NR2
Ethers, -OR
Alkyl groups are also weakly electron-donating.
Electron withdrawing groups
EWGs make electrophiles stronger, because the electron-withdrawing effect makes any carbon center even more electron deficient than before.
EWGs make any nucleophilic species less reactive, for the same reason as they strengthen electrophiles. Nucleophiles need electron density to react with electrophiles
Nitro groups (-NO2)
Aldehydes (-CHO)
Ketones (-C=OR)
Cyano groups (-CN)
Carboxylic acid (-COOH)
Esters (-COOR)
A reducing sugar is
any sugar that is capable of acting as a reducing agent. In an alkaline solution, a reducing sugar forms some aldehyde or ketone, which allows it to act as a reducing agent, for example in Benedict’s reagent
Unit breakdown:
Watts
Coulomb
Pascal
Volts
Ohm
Watts: J / s
Coulomb: Apmere x sec (Ampere = current)
Pascal: N / m2
Volts: W / Ampere
Ohms: V / Ampere
Tera
Giga
Mega
Deci
Centi
Micro
Nano
1012
109
106
10-1
10-2
10-6
10-9
quinone
derived from benzenes
aliquot
a portion of a larger whole, especially a sample taken for chemical analysis or other treatment.
phosphatide
any of a class of compounds which are fatty acid esters of glycerol phosphate with a nitrogen base linked to the phosphate group.
Extensive conjugation will cause
color to appear in organic compounds.
Electron delocalization
2nd law of thermodynamics:
∆Suniverse ≥ 0
The entropy of a system will naturally increase over time
- entropy (S) = energy not available to do work
If two objects are in contact but not thermal equilibrium, heat energy will spontaneously go from higher to lower temp
- ∆S = Q/T
Entropy can decrease but it requires input of energy, however entropy of surroundings increase more so entropy of universe increases
Heat capacity vs. specific heat
Heat capacity is the heat required to raise the temperature of an object by a certain unit of temperature.
Specific heat as the amount of heat required to raise one gram of an object by one degree Kelvin (or Celsius).
Isothermal processes:
Adiabatic processes:
Isovolumetric(iscochoric) processes:
Isothermal processes: constant temperature and therefore ∆U = 0
Adiabatic processes: heat is not exchanged and Q = 0
Isovolumetric processes: the volume cannot change, work cannot be done, and therefore W = 0
Calorimetry
technique that allows for the calculation of heat transfer associated with chemical or physical reactions using a tool called a calorimeter under specific constraints
For a bomb calorimeter, contains a reaction and a fluid with different variables which can exchange heat
use qr=qc
- mc∆T (of reactants) = mc∆T (of products)
Thermodynamic products are favored at
high temperatures, have lower energy, and are more stable.
However, their formation occurs more slowly because greater activation energy is required.
Kinetic products are favored at
a lower temperature, have higher energy, and are less stable.
Their formation occurs more quickly because smaller activation energy is required.
- Product B is kinetic, Product A is thermodynamic
The intermediate step with the highest activation energy is known as the
rate-limiting or rate-determining step, since the velocity of the overall reaction is limited by the slowest step.
What increases reaction rate
Temp and pressure
Solubility rules to know
All salts in group 1 are soluble (Na, K, Li)
All nitrates salts soluble
E/Z nomenclature
Use priority to find is highest priority groups are on same or opposite sides of double bond
- same = Z
- different = E
Pressure units
1 atm = 760 torr = 760 mmHg = 101 kPa
Within how many pKa’s is a good buffer
pH = pKa +/- 1
Alpha and beta carbohydrates differ in
how the straight-line molecules cyclize.
alpha isomer: the -OH group linked to the anomeric carbon points opposite, or underneath, the in-ring oxygen.
beta isomers: can be identified when the -OH group is linked to the anomeric carbon points in the same direction as, or above, the in-ring oxygen.
Lactones/lactonization
unsaturation or heteroatoms replacing one or more carbon atoms of the ring.
A carbamate is a
category of organic compounds that is formally derived from carbamic acid (NH2COOH)
Sequential reactions (ternary)
Ordered
Random
Double displacement
All substrates (A and B) must bind to active site to form ternary structure before enzyme can convert them to product
ordered: substrates bind to active site in specific order and products leave in specific order (ex. glycolysis)
random: binding order doesn’t matter
double-displacement (ping pong): first substrate binds and forms intermediate ES complex which converts it to first product, THEN next substrate binds and does the same
Is keto or enol preferred?
Keto
Divalent
Having a velence of 2
Cytochromes are
proteins that are involved in redox reactions. Specifically, cytochrome P450 acts as a monooxygenase, catalyzing an oxidation reaction.
Phosphorylation of an OH group
Removes hydrogen, binds to oxygen
Sucrose
Lactose
Maltose
Sucrose- table sugar; composed of glucose and fructose
Lactose- dairy products galactose and glucose
- majority of world’s adults lack lactase, lactose intolerant
- all mammals express lactase in childhood for breast milk but expression turns off
- northern european and african heritages continue expression
Maltose- two glucose monomers; less sweet than sucrose
Entropy equation (3rd law of thermodynamics)
S = H/T
Convection is
Heat transfer via movement of liquids
**inside of cell is rich in
negative aminos and K+, outside of cell is rich in Ca2+, Na+, and Cl-
Volatile =
Low melting and boiling points, low polarity
ex. alkanes very volatile
think of the order of intermolecular bonds: ion-dipole, hydrogen bonding , dipole-dipole, london disperson
Normality
Number of equivalent weights x molarity
N1V1 = N2V2
molality (colligative properties)
moles solute / kg solvent
Native PAGE vs. SDS page (reducing and nonreducing)
Native page analyzes size and 3D structure and charge
SDS page reduces folding and charge, just size
- reducing vs. nonreducing (disulfide bonds): if divided into two additional sub units if they are held by disulfide bonds, then the reducing SDS PAGE would separate into 4 subunits whereas nonreducing SDS PAGE would reduce into just 2.
Reducing Agents
Oxidizing agents
Reducing:
NaBH4 -weak
LiAlH4 strong
Oxidizing agents:
Na2Cr2O7 - sodium dichromate
CrO3 - chromium trioxide
PCC
