AAMC MCAT PRACTICE EXAM 1
QUESTIONS AND ANSWERS GRADED A+
2025/2026
In the chromatography of the reaction mixture, water absorbed on cellulose functioned as the
stationary phase. What was the principal factor determining the migration of individual
components in the sample?
A) Hydrogen bonding
B) Solute concentration
C) Stationary phase concentration
D) Thickness of paper - ANS A) Hydrogen bonding
The answer to this question is A because the relative amount of hydrogen bonding to the
stationary phase will determine the relative rate of migration of the various components in the
sample.
What assumption is being made if scientists conclude that aspartic acid was formed by the
prebiological synthesis in the passage?
A) Aspartic acid is unstable at temperatures below 150 degrees C.
B) All of the malic acid underwent the dehydration reaction to form fumaric/maleic acid.
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,C) Compound A and cyanide were available on primitive Earth.
D) The reaction between ammonia and fumaric acid was catalyzed by the presence of water. -
ANS C) Compound A and cyanide were available on primitive Earth.
he answer to this question is C since, in order for the experimental reaction sequence to be
relevant to the primordial formation of aspartic acid, the starting materials used (Compound A
and cyanide) are assumed to have been available.
According to the developed chromatography plate shown below, what is the approximate Rf
value of aspartic acid?
aspartic acid = 2
solvent front = 10
A) 0.20
B) 0.50
C) 5
D) 10 - ANS The answer to this question is A (0.20) because Rf is the ratio of the distance
travelled by the analyte relative to the solvent front during a chromatographic separation.
Aspartic acid travelled two units, while the solvent front travelled ten units, giving an Rf of 2/10
= 0.20 for aspartic acid.
Which of the following statements does NOT correctly describe the dehydration of malic acid to
fumaric acid and maleic acid?
A) The reaction occurs most readily with tertiary alcohols.
B) The reaction involves the loss of a water molecule.
C) The reaction has a carbocation intermediate.
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,D) The reaction is stereospecific. - ANS D) The reaction is stereospecific.
The answer to this question is D because the fact that both fumaric and maleic acid are
produced means that the dehydration of malic acid is NOT stereospecific.
What type of functional group is formed when aspartic acid reacts with another amino acid to
form a peptide bond?
A) An amine group
B) An aldehyde group
C) An amide group
D) A carboxyl group - ANS C) An amide group
The answer to this question is C because the functional group that forms during peptide bond
formation is known as an amide group.
If 2-pentanol replaces 1-pentanol in the reaction shown in Figure 3 (SN2), the rate of
substitution is less because:
A) the C-O bond in 2-pentanol is stronger than the C-O bond in 1-pentanol.
B) there is a competing elimination reaction that slows the rate of substitution.
C) there is more steric hindrance at the oxygen atom in 2-pentanol than in 1-pentanol, making
protonation less likely.
D) there is more steric hindrance at the 2-position of 2-pentanol than at the 1-position of 1-
pentanol. - ANS D) there is more steric hindrance at the 2-position of 2-pentanol than at the
1-position of 1-pentanol.
The answer to this question is D because the rate of substitution of protonated alcohols is
subject to steric hindrance. This inhibits the ability of nucleophiles to collide with the reacting
electrophilic center and slows the rate of reaction.
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, If a solution containing the compounds shown in Figure 4, is injected into a gas-liquid
chromatograph, the first peak observed in the gc trace is attributable to which compound?
A) Methyl-2-butanol
B) Methyl-2-butene
C) Chloro-2-methylbutane
D) Bromo-2-mehtylbutane - ANS B) Methyl-2-butene
The answer to this question is B because 2-methyl-2-butene will exhibit the lowest molecular
weight and also the weakest intermolecular forces of attraction. This substance will therefore
migrate the fastest and be the first peak in the gas chromatograph (gc) trace.
R vs. S stereochemistry* - ANS R = clockwise
C = counter-clockwise
Acetic acid and ethanol react to form an ester product as shown below.
In determining which reactant loses the -OH group, which of the following isotopic substitutions
would be most useful?
A) Replace the acidic H of acetic acid with D
B) Replace the alcoholic H of ethanol with D.
C) Replace the carbonyl oxygen of acetic acid with O-18.
D) Replace the hydroxyl oxygen of ethanol with O-18. - ANS D) Replace the hydroxyl oxygen
of ethanol with O-18.
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QUESTIONS AND ANSWERS GRADED A+
2025/2026
In the chromatography of the reaction mixture, water absorbed on cellulose functioned as the
stationary phase. What was the principal factor determining the migration of individual
components in the sample?
A) Hydrogen bonding
B) Solute concentration
C) Stationary phase concentration
D) Thickness of paper - ANS A) Hydrogen bonding
The answer to this question is A because the relative amount of hydrogen bonding to the
stationary phase will determine the relative rate of migration of the various components in the
sample.
What assumption is being made if scientists conclude that aspartic acid was formed by the
prebiological synthesis in the passage?
A) Aspartic acid is unstable at temperatures below 150 degrees C.
B) All of the malic acid underwent the dehydration reaction to form fumaric/maleic acid.
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,C) Compound A and cyanide were available on primitive Earth.
D) The reaction between ammonia and fumaric acid was catalyzed by the presence of water. -
ANS C) Compound A and cyanide were available on primitive Earth.
he answer to this question is C since, in order for the experimental reaction sequence to be
relevant to the primordial formation of aspartic acid, the starting materials used (Compound A
and cyanide) are assumed to have been available.
According to the developed chromatography plate shown below, what is the approximate Rf
value of aspartic acid?
aspartic acid = 2
solvent front = 10
A) 0.20
B) 0.50
C) 5
D) 10 - ANS The answer to this question is A (0.20) because Rf is the ratio of the distance
travelled by the analyte relative to the solvent front during a chromatographic separation.
Aspartic acid travelled two units, while the solvent front travelled ten units, giving an Rf of 2/10
= 0.20 for aspartic acid.
Which of the following statements does NOT correctly describe the dehydration of malic acid to
fumaric acid and maleic acid?
A) The reaction occurs most readily with tertiary alcohols.
B) The reaction involves the loss of a water molecule.
C) The reaction has a carbocation intermediate.
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,D) The reaction is stereospecific. - ANS D) The reaction is stereospecific.
The answer to this question is D because the fact that both fumaric and maleic acid are
produced means that the dehydration of malic acid is NOT stereospecific.
What type of functional group is formed when aspartic acid reacts with another amino acid to
form a peptide bond?
A) An amine group
B) An aldehyde group
C) An amide group
D) A carboxyl group - ANS C) An amide group
The answer to this question is C because the functional group that forms during peptide bond
formation is known as an amide group.
If 2-pentanol replaces 1-pentanol in the reaction shown in Figure 3 (SN2), the rate of
substitution is less because:
A) the C-O bond in 2-pentanol is stronger than the C-O bond in 1-pentanol.
B) there is a competing elimination reaction that slows the rate of substitution.
C) there is more steric hindrance at the oxygen atom in 2-pentanol than in 1-pentanol, making
protonation less likely.
D) there is more steric hindrance at the 2-position of 2-pentanol than at the 1-position of 1-
pentanol. - ANS D) there is more steric hindrance at the 2-position of 2-pentanol than at the
1-position of 1-pentanol.
The answer to this question is D because the rate of substitution of protonated alcohols is
subject to steric hindrance. This inhibits the ability of nucleophiles to collide with the reacting
electrophilic center and slows the rate of reaction.
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, If a solution containing the compounds shown in Figure 4, is injected into a gas-liquid
chromatograph, the first peak observed in the gc trace is attributable to which compound?
A) Methyl-2-butanol
B) Methyl-2-butene
C) Chloro-2-methylbutane
D) Bromo-2-mehtylbutane - ANS B) Methyl-2-butene
The answer to this question is B because 2-methyl-2-butene will exhibit the lowest molecular
weight and also the weakest intermolecular forces of attraction. This substance will therefore
migrate the fastest and be the first peak in the gas chromatograph (gc) trace.
R vs. S stereochemistry* - ANS R = clockwise
C = counter-clockwise
Acetic acid and ethanol react to form an ester product as shown below.
In determining which reactant loses the -OH group, which of the following isotopic substitutions
would be most useful?
A) Replace the acidic H of acetic acid with D
B) Replace the alcoholic H of ethanol with D.
C) Replace the carbonyl oxygen of acetic acid with O-18.
D) Replace the hydroxyl oxygen of ethanol with O-18. - ANS D) Replace the hydroxyl oxygen
of ethanol with O-18.
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