PCAT Chemistry Practice Questions
1. At what level is an electron in its lowest energy state?
A: low level
B: ground state level
C: high state level
D: solid state level
2. Which rule states that within a given subshell, the orbitals will be filled up such that there
is a maximum number of half-filled orbitals with parallel spins?
A: Ohm's law
B: Planck's law
C: Hund's law
D: Heisenberg's law
3. Which of the following is NOT one of the three general types of chemical systems?
A: open
B: isolated
C: linked
D: closed
4. Which rule states that the rate of a chemical reaction will be proportional to the number of
collisions per second between the reacting molecules?
A: exclusion theory
B: collision theory
C: misdirection theory
D: construction theory
5. What is another name for heat changes at constant pressure?
A: entropy
B: enthalpy
C: dystrophy
D: endoscopy
6. Which equation is used to estimate the pH of a solution in the region where the concentrations
of the species and its conjugate are present in approximately equal proportions?
A: Halpert equation
B: Henderson-Hasselbalch equation
C: Martin-Hunt equation
D: Maxwell equation
7. Which concept asserts that the total number of neutrons and protons remains the same, even if
the protons are converted to neutrons or vice versa?
A: baryon number conservation
B: nucleotide conservation
C: kinetic conservation
D: orbital conservation
8. Which law states that the total pressure of a gaseous system is equal to the sum of the
partial pressures of the individual components?
A: Gault's law of partial pressures
B: Johnson's law of partial pressures
C: Haggard's law of partial pressures
D: Dalton's law of partial pressures
9. Which phrase describes dilution?
A: a solvent is added to a solution of low concentration, resulting in a solution of lower
concentration
B: a solvent is added to a solution of high concentration, resulting in a solution of lower
concentration
C: two solutions are separated
D: a solution is extracted, resulting in a high concentration of the solution
10. What element is in every organic compound?
A: carbon
B: nitrogen
C: oxygen
D: iron
Answer Key
1. B. An electron at ground state level is at its lowest possible energy level.
2. C. Hund's law governs the degree to which orbital layers are filled.
3. C. Open, closed, and isolated systems are the three general types of chemical systems.
4. B. The collision theory describes the rate of a chemical reaction.
5. B. Enthalpy is the name used to describe any changes in heat that occur at constant pressure.
6. B. The Henderson-Hasselbalch equation is used to describe the pH of a solution in areas of equal concentration.
7. A. The concept of baryon number conservation asserts that the total number of protons and neutrons cannot be altered.
8. D. Dalton's law of partial pressures describes the total pressure of a gaseous system.
9. B. In dilution, a solution decreases in concentration.
10. A. In order to be classified as organic, a compound must include carbon.