MCAT Question of the day

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The pH Value Is Right

Which set of 1 Molar solutions has the correct pH values?


A. Water pH = 0; hydrochloric acid pH = 4; acetic acid pH = 7; ammonia solution pH = 10; sodium hydroxide solution pH = 14.

B. Acetic acid pH = 0; hydrochloric acid pH = 4; water pH = 7; sodium hydroxide solution pH = 10; ammonia solution pH = 14.

C. Sodium hydroxide solution pH = 0; ammonia solution pH = 4; water pH = 7; acetic acid pH = 10; hydrochloric acid pH = 14.

D. Hydrochloric acid pH = 0; acetic acid pH = 4; water pH = 7; ammonia solution pH = 10; sodium hydroxide solution pH = 14.

To see the answer to today’s question, visit the following link:
http://mcatquestionoftheday.com/chemistry/the-ph-value-is-right/

Optically Active

_____________ refers to the method by which an optically reactive reagent or catalyst is used to transform an optically inactive starting material into an optically active product.


A. Racemization

B. Enantioenrichment

C. Chiral chromatography

D. Asymmetric induction

To see the answer to today’s question, visit the following link:
http://mcatquestionoftheday.com/chemistry/optically-active/

Favored Reaction in Thermodynamics

According to the second law of thermodynamics, which of the following reactions would be favored?


A. 2H2O + O2 → 2H2O2

B. ADP + Pi → ATP

C. 2H2O2 → 2H2O + O2

D. 2Na + Cl2 → 2NaCl

To see the answer to today’s question, visit the following link:
http://mcatquestionoftheday.com/biology/favored-reaction-in-thermodynamics/

Know Your Thermo

Describe the reaction below:


PCl3(g) + Cl2(g) -> PCl5(g) ; Delta(Hf) = -87.9kJ/mol

A. spontaneous at all temperatures.

B. nonspontaneous at all temperatures.

C. ΔGrxn is less than 0 at only low temperatures.

D. spontaneous at only high temperatures.

To see the solution, visit the following link:
http://mcatquestionoftheday.com/chemistry/know-your-thermo/

Genetic Drift Effects

Genetic drift is the process responsible for:


A. gaining a new allele within large populations.

B. gaining a new allele within sufficiently small populations.

C. losing an existing allele due to emigration.

D. losing an existing allele due to random sampling.

To see the solution, visit the following link:
http://mcatquestionoftheday.com/biology/genetic-drift-effects/

Rates of Consumption

During the reaction to form ammonia from nitrogen and hydrogen according to the reaction: N2(g) + 3 H2(g) <-> 2 NH3(g), ammonia was being produced at the rate of 1.50 mol.L-1.s-1. What were the respective rates of consumption of nitrogen and hydrogen at this time?


A. N2(g) 1.50 and H2(g) 1.50 mol.L-1.s-1.

B. N2(g) 2.25 and H2(g) 0.75 mol.L-1.s-1.

C. N2(g) 0.75 and H2(g) 2.25 mol.L-1.s-1.

D. N2(g) 3.00 and H2(g) 1.00 mol.L-1.s-1.

To see the answer to today’s question, visit the following link:
http://mcatquestionoftheday.com/chemistry/rates-of-consumption/

Law of Independent Assortment

Mendel’s second law, the Law of Independent Assortment, states that each trait assigned to offspring is done so without regard to any other trait assigned. In a dihybrid cross of two dogs, one that is black with a short tail and the other that is white with a long tail, the inheritance of one fur color is not dependent upon the inheritance of tail length. Assuming that black fur is dominant and a long tail is dominant and each parent is homozygous for each trait, how many offspring in the F2 generation will be white with a short tail?


A. 0

B. 1/16

C. 3/16

D. 9/16

To see the answer to today’s question, visit the following link:
http://mcatquestionoftheday.com/chemistry/law-of-independent-assortment/

Jan 8

Bond Angles

Which of the following is closest to the bond angle of an sp2-hybridized carbon atom?


A. 180o

B. 140o

C. 120o

D. 110o

To see the answer to today’s question, visit the following link:
http://mcatquestionoftheday.com/chemistry/bond-angles/

Jan 7

Simple Harmonic Motion

An object undergoing simple harmonic motion is observed to have a time interval of 4 seconds between the two extremes of its displacement from equilibrium. What is the frequency of this motion?


A. 0.125 cycles/second

B. 0.25 cycles/second

C. 1.25 cycles/second

D. 4 cycles/second

To see the answer to today’s question, visit the following link:
http://mcatquestionoftheday.com/physics/simple-harmonic-motion/

Jan 3

Rate of Chemical Reaction

The rate at which a chemical reaction occurs is dependent on many factors. Which of the following will increase the rate of reaction?


A. Decreasing the temperature.

B. Adding a catalyst.

C. Decreasing the concentration of a reactant in solution.

D. Decreasing the partial pressure of a reactant gas.

To see the answer to today’s question, visit the following link:
http://mcatquestionoftheday.com/chemistry/rate-of-chemical-reaction/