MCAT: Chemistry and Physics

How do you determine the total number of stereoisomers of a compound?

2 to the power of the number of chiral centers in the compound

When does precipitation happen? (In regards to Ksp)

When the reaction quotient Qsp exceeds the equilibrium constant Ksp

Alanine

Arginine

Asparagine

Aspartate

Cysteine

Glutamate

Glutamine

Glycine

Histidine

Isoleucine

Leucine

Lysine

Methionine

Phenylalanine

Proline

Serine

Threonine

Tryptophan

Tyrosine

Valine

A (amino acid)

Alanine

R (amino acid)

Arginine

N (amino acid)

Asparagine

D (amino acid)

Aspartate

C (amino acid)

Cysteine

E (amino acid)

Glutamate

Q (amino acid)

Glutamine

G (amino acid)

Glycine

H (amino acid)

Histidine

I (amino acid)

Isoleucine

L (amino acid)

Leucine

K (amino acid)

Lysine

M (amino acid)

Methionine

F (amino acid)

Phenylalanine

P (amino acid)

Proline

S (amino acid)

Serine

T (amino acid)

Threonine

W (amino acid)

Tryptophan

Y (amino acid)

Tyrosine

V (amino acid)

Valine

How do electrical feild lines move in regard to charge?

Exit positive charges and enter negative charges

How does a myelin sheath effect transmission and capacitance in an axon?

Increases rate of transmission of signals and decreases capacitance

How does insulation affect signalling?

Insulation acts to increase the rate of transmission of signals

How do you calculate current?

Potential(voltage) over resistance

How do you calculate potential(voltage)?

Current times resistance

How do you calculate pH based on hydronium ion concentration?

pH=-log([H3O+])

What are oxyacids?

Acids where the hydrogen was directly bound to an oxygen

What structure allows hemiacetal ring opening?

An alcohol and ether directly bound to the same carbon

What is the y-intercept on a Lineweaver-Burk plot?

1/Vmax

When NADPH becomes NADP+, what kind of agent is it functioning as?

Reducing agent because it donates electrons

What is the ideal gas equation?

PV=nRT

How do you calculate frequency of sound from the perspective of an observer that the source is moving towards?

How do you calculate frequency of sound from the perspective of an observer that the source is moving away from?

Which elements can take part in H-bonds?

N O F

What does the principal quantum number measure?

The primary shell that the electron orbits in but it also indicates potential energy and radial size of the electron cloud

If an enzyme’s ligand is anionic and hydrophobic, what kinds of amino acids would you most likely find in the binding site?

Cationic and hydrophobic

How do you calculate for density?

Mass over volume

Which direction do electrons flow?

Negative to positive

How do you calculate heat required/absorbed?

q = mc∆T (q=heat transferred; c=specific heat)

What is the stretching frequency of a carbonyl?

1670-1780 cm^-1

What is the stretching frequency of an alcohol?

3400-3650 cm^-1

What is the stretching frequency of an alkene double bond?

1640-1680 cm^-1

How can a single steroisomer form if neither reactant is chiral?

The enzyme could be chiral

How can water be removed from a frozen aqueous protein sample?

Sublimation under reduced pressure

What is stated by Archimedes’ principle?

The buoyant force acting on a submerged object is equal to the weight of the liquid displaced

What is equal to the loss in weight of an object in liquid as opposed to air?

buoyant force

Charge of hydroxyl at pH 7

Neutral

Charge of methyl at pH 7

neutral

Charge of amine at pH 7

Postitive

Charge of carboxylic acid at pH 7

Negative

Charge of phosphate at pH 7

Negative

Charge of sulfhydryl at pH 7

neutral

What kind of amino acids would attract and stabilize ADP?

Basic(positively charged amino acids)

How do you calculate energy of a photon?

E=hf where h is Plank’s constant and f is frequency

How are keV and J related?

J=e*keV where e is the elementary charge

How do you calculate work based on power?

W=t*P where time is in seconds and power is in watts

How does stationary phase concentration affect chromotography?

Trick question: stationary phase doesn’t have a concentration since it is not a solution

How does solute concentration affect chromatography?

It will affect the size of the spots

How does paper thickness affect chromatography?

It will affect the amound of each component that can be fully separated

True or False: Tertiary alcohols readily dehydrate

True

What kind of compounds will create the first peaks in gas-liquid chromotography?

The least polar, most volatile compounds(due to weak intermolecular forces)

What configuration is this?

R

What configuration is this?

S

How do SN2 and SN1 reactions differ in rate law?

SN2 depends on both substrate and nucleophile concentration; SN1 only depends on substrate

What is a polar protic solvent?

A polar solvent that can hydrogen bond(like water or acetic acid)

How do SN2 and SN1 reactions differ in biggest barrier?

SN2’s biggest barrier is steric hindrance meaning primary alkyl halides will be easier to attack; SN1’s biggest barrier is carbocation stability meaning tertiary alkyl halides will be easier to attack

How do SN2 and SN1 reactions differ in nucleophile?

SN2 strong; SN1 weak

How do SN2 and SN1 reactions differ in solvent?

SN2 polar aprotic; SN1 polar protic

How do SN2 and SN1 reactions differ in stereochemistry?

SN2 results in inversion only; SN1 results in mix of inversion and retention

How do you calculate index of refraction?

speed of light in a vacuum/speed of light in medium

What is the intensity of radiation emitted proportional to?

number of photons emitted per unit time and their respective frequency

What is Hz a measurement of?

frequency (1Hz= 1/s)

What is 1 THz in Hz?

10¹² Hz

What is standard atmospheric pressure?

760 mmHg, 1 atm, ~101 kPa

What type of interactions are disulfide bridges?

Intermolecular covalent bonding

Why is the velocity of blood slower in capillaries than in arteries?

The total cross sectional area of all capillaries together exceeds that of arteries

What type of orbitals are involved in octahedral compounds?

d²sp³(6 sigma bonds)

What is the ideal gas constant?

R = 0.08206 (L*Atm)/(mol*K)