MCAT Test 16 (Princeton Review Test 1)
2025 LATEST EXAM SET WITH
QUESTIONS AND SIMPLIFIED CORRECT
ANSWERS
Mercury has a greater density than water, so what can we say about the buoyant force and the force of
surface tension? - correct answer-The buoyant force and surface tension are both greater in Mercury
What explains why a water droplet forms a roughly spherical shape if not acted upon by external forces?
- correct answer-A sphere minimizes the surface area of the shape for a given volume, which yields the
lowest-energy state for the molecules.
Units of surface tension coefficient - correct answer-
What would happen if an aluminum coin (ρ = 2700 kg/m3, L = 1 cm, V = 1 × 10-8 m3) were gently placed
on the surface of water? - correct answer--The force of surface tension by itself would be sufficient to
make the coin float.
-The maximum buoyant force for the coin is given by Fb = ρfVsubg, which for the given situation is Fb =
(1000)(10-8)(10) = 10-4 N. The weight of the coin is w = mg = ρcoinVg = (2700)(10-8)(10) = 2.7 × 10-4 N.
The weight is greater than the buoyant force, so eliminate choice A: the buoyant force alone is not good
enough. The maximum force of surface tension is Fst,y = γL (twice, because the passage says that there
are two of them). This comes out to Ftotal surface tension = (2)(0.07)(0.01) = 1.4 × 10-3 N. That's greater
than the weight, so the surface tension alone can balance the weight and allow the coin to float.
What explains why F2 is higher than Cl2 in the reactivity series? (what makes F2 more reactive than Cl2) -
correct answer--F2 has a more negative Δ(SE)° than Cl2
-if the Δ(SE)° is more negative for F2, the overall ΔG° is more negative indicating it is more energetically
favorable to add an electron to F2 compared to Cl2.
What best explains the observed difference in electron affinity between chlorine and fluorine? - correct
answer-Fluorine has a smaller atomic volume than chlorine, resulting in stronger repulsive forces
between the existing electrons and the electron being added
The smaller atomic volume leads to greater repulsive forces between the existing electrons and the
electron being added
A medium with index of refraction n is surrounded by air. The critical angle inside of the medium is then
determined. The medium is then submerged in a fluid with index of refraction nfluid. If 1 < nfluid < n
how is the critical angle affected? - correct answer--It is measured inside of the medium and is greater
than its previous value
-Total internal reflection can only happen when the incident medium has a greater index of refraction
than the surrounding medium. Since the original medium has a greater index of refraction than the fluid,
it must still be the incident medium.
,-Snell's law of refraction states that n1sinθ1 = n2sinθ2. For total internal reflection, θ1 = θcritical and θ2
= 90°, which means that n1sinθcritical = n2. The index of refraction of air (n2 in this case) is 1, so
immersing the medium in fluid has caused n2 to increase. Since n1 remains constant, the equation tells
us that sinθcritical, and therefore θcritical itself, must increase.
The more negative the H0 of a superacid is means what? - correct answer-The more negative, the
stronger the acid
What are the three major ways in which antibiotics interact with bacteria? - correct answer--Membrane
protein solubilization
-Leakage of cytosolic content
-Detergent fro the cell membrane
If a substrate has a positive charge on it, what kind of amino acid would most likely be in the active site?
- correct answer--One with a positive charge like aspartic or glutamic acid- positive charge means
negatively acidic amino acids and vice versa
Why is CH3F unlikely to methylate something? - correct answer--Fluorine is a very unlikely leaving group,
so it is unlikely to leave the -CH3 group that it is bonded to
Can KHSO4 and NH4Cl lower the pH of a solution? - correct answer-Yes, they will
The conjugate acid of a weak base will lower the pH, while the conjugate base of a weak acid will raise it.
Conjugates of strong acids or bases have no effect on pH. NH4+, the conjugate of the weak base NH3, is
acidic.
K+ and HSO4- are conjugates of a strong base and strong acid, respectively. Generally this would indicate
a neutral salt. However, the HSO4- ion is acidic in its own right and will lower the pH
Carnitine deficiency is an example of a medical condition affecting the metabolism of fatty acids. Which
of the following would you expect to see in the cells of an individual with this condition? - correct
answer-Accumulation of fatty acids in the cytosol and decreased β-oxidation activity
Carnitine allows transport of fatty acids from the cytosol into the mitochondria. The lack of carnitine
would mean that cells would accumulate fatty acids in the cytosol.
β-oxidation occurs inside the mitochondrial matrix. If fatty acids cannot enter the mitochondria, β-
oxidation activity would decrease
Release of which of the following peptides will increase the activity of β-oxidation? - correct answer-
Glucagon and epinephrine
Why is radon not used fro smoke alarms? - correct answer-Its decay releases hazardous gases
In a fluorescence units/ sec mg protein vs [Cation] graph, what can you conclude about a transporter if
one ion levels off and the other continues to increase on the graph? - correct answer--If one levels off,
than we can conclude that the transporter has a greater affinity fro it than the other ion
, What does a mixed inhibitor do? - correct answer-A mixed inhibitor will always decrease the Vmax but
the Km can either increase or decrease
Protein folding involves both the formation of secondary and tertiary protein structure to ultimately
generate a stereotyped final configuration. What is true of the folding process? - correct answer--The
Gfolded is smaller than Gunfolded
-Secondary and tertiary protein structure largely depends upon the formation of weak interactions
including both hydrogen bonding and Van der Waals forces. Formation of these interactions will release
energy resulting in a negative ΔH
-The folding process occurs spontaneously in order to reach an energy minimum and having multiple
potential final folded products would likely not result in a functional protein
-Burial of polar amino acids in what is most frequently a nonpolar interior would significantly decrease
the stability of the folded state
The standard reduction potentials (E°) of Cl2 and Na+ are 1.36 V and -2.71 V respectively. What is the
standard free energy change in the following reaction (F = 96,485 C/mol e-, 1 V = 1 J/C)?
Cl2 + 2Na -> 2NaCl - correct answer--The solution requires the formula ΔG° = -nFE°. By summing the
voltages for the oxidation of Na (2.71 V) and the reduction of Cl2 (1.36 V) we arrive at a total voltage
change for the reaction of +4.07 V. Since E° is positive, the answer must be negative
-Substitute +4.07 volts into the equation, using an approximate value of F ~ 10^5:
ΔG° = -(2)(105)(4) = -8 × 10^5 J.
A monochromatic beam used in DEI is composed of photons with an energy of 30 keV. What is
wavelength of the photons that reach the imaging screen after diffracting from an analyzer angle of Δθ =
5 μrad? (Planck's constant h = 4.14 × 10-15 eV·s.) - correct answer-The relation between photon energy
and wavelength is given by E = hc / λ, so λ = hc / E = (4.14 × 10-15 eV·s × 3 × 108 m/s) / (30 × 103 eV) =
4.1 × 10-11 m.
The analyzer angle does not affect the energy of a given photon, but rather the number of photons that
reflect toward the screen (beam intensity being proportional to number of photons)
A 42 year-old female presents with hemolytic anemia (inappropriate destruction of red blood cells)
secondary to a pyruvate kinase deficiency (the final enzyme in glycolysis). What best describes the
mechanism of her hemolytic anemia? - correct answer--Inadequate ATP resulting in failure of primary
active transport and subsequent cell damage
-A deficiency in the final enzyme of glycolysis would significantly reduce ATP production and in red blood
cells, which lack mitochondria, glycolysis is the principal source of ATP. Pumps relying on ATP, primary
active transporters, would fail leading to cell damage; the damaged cells would then ultimately be
consumed by a macrophage in the spleen
A researcher bubbles excess oxygen through a solution containing Ag2S, waits five minutes, and
concludes that no detectable reaction occurred. She leaves the reaction on her bench overnight, and
