AAMC MCAT Chemical and Physical Foundations

Question 1

What does a negative ΔG value indicate about a chemical reaction?

Accepted Answer

The reaction is spontaneous and releases free energy

Answer

A negative ΔG (exergonic reaction) indicates spontaneity — the reaction releases free energy and proceeds without added energy.

Question 2

According to Boyle's Law, if volume is halved at constant temperature, what happens to pressure?

Accepted Answer

Pressure doubles

Answer

Boyle's Law states pressure and volume are inversely proportional at constant temperature: halving volume doubles pressure.

Question 3

What is the significance of pH = pKa in a buffer solution?

Accepted Answer

The acid and conjugate base are in equal concentrations

Answer

At pH = pKa (Henderson-Hasselbalch midpoint), [HA] = [A⁻], meaning exactly half the acid is dissociated and buffer capacity is maximal.

Question 4

Which quantum number describes the shape of an atomic orbital?

Accepted Answer

Azimuthal quantum number (l)

Answer

The azimuthal quantum number (l) defines orbital shape: l=0 is spherical (s), l=1 is dumbbell-shaped (p), l=2 is d.

Question 5

What does a high Reynolds number indicate about fluid flow?

Accepted Answer

Turbulent flow where inertial forces dominate

Answer

A high Reynolds number (>4000) signals turbulent flow where inertial forces overwhelm viscous forces, creating chaotic mixing.

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