CHEM 103 (General Chemistry) Module 6
2026 CHEM 103 (General Chemistry)
Module 6 Practice Exam 100 Questions
and Answers with Rationales
Gas Laws & Molecular Behavior
1. Which gas law relates pressure and volume at constant temperature?
A. Charles’s Law
B. ✅✅ Boyle’s Law
C. Avogadro’s Law
D. Hess’s Law
Answer: ✅✅ B
Rationale: Boyle’s Law states pressure is inversely proportional to volume when temperature is
constant.
2. If the pressure of a gas increases while temperature remains constant, the
volume will:
A. Increase
B. ✅✅ Decrease
C. Stay constant
D. Become zero
Answer: ✅✅ B
Rationale: Boyle’s Law (P↑ → V↓).
3. Which equation correctly represents the Ideal Gas Law?
A. PV = nRT²
B. P/V = nRT
C. ✅✅ PV = nRT
D. Pn = RT
, CHEM 103 (General Chemistry) Module 6
Answer: ✅✅ C
Rationale: The ideal gas law relates pressure, volume, moles, and temperature.
4. A gas sample contains 2.0 mol at 300 K and 1 atm. What happens if
temperature increases at constant pressure?
V1T1=V2T2\frac{V_1}{T_1} = \frac{V_2}{T_2}T1V1=T2V2
V1T1=12300=V2T2=18450\frac{V_1}{T_1}=\frac{12}{300}=\frac{V_2}{T_2}=\frac{18}{45
0}T1V1=30012=T2V2=45018
V1V_1V1
L
T1T_1T1
K
V2V_2V2
L
T2T_2T2
K
State 1: 300 K, 12 LState 2: 450 K, 18 L
A. Volume decreases
B. Pressure increases
C. ✅✅ Volume increases
D. Moles decrease
Answer: ✅✅ C
Rationale: Charles’s Law: volume is directly proportional to temperature.
5. Which condition causes real gases to deviate most from ideal behavior?
A. High temperature, low pressure
B. ✅✅ Low temperature, high pressure
C. High temperature, high volume
D. Low pressure, high temperature
, CHEM 103 (General Chemistry) Module 6
Answer: ✅✅ B
Rationale: Particle interactions become significant under low T and high P.
Stoichiometry & Molarity
6. Molarity is defined as:
M=nVM = \frac{n}{V}M=Vn
M=1.2 mol0.8 L=1.5 mol/LM=\frac{1.2\,\mathrm{mol}}{0.8\,\mathrm{L}}=1.5\,\mathrm{mol/
L}M=0.8L1.2mol=1.5mol/L
nnn
mol
VVV
L
A. grams per mole
B. liters per mole
C. ✅✅ moles per liter of solution
D. moles per kilogram
Answer: ✅✅ C
Rationale: Molarity measures concentration in mol/L.
7. How many moles are in 2.0 L of a 0.50 M solution?
A. 0.10 mol
B. 0.50 mol
C. ✅✅ 1.0 mol
D. 2.5 mol
Answer: ✅✅ C
Rationale:
n=MV=(0.50)(2.0)=1.0 moln = MV = (0.50)(2.0)=1.0\text{ mol}n=MV=(0.50)(2.0)=1.0 mol
, CHEM 103 (General Chemistry) Module 6
8. Dilution equation is expressed as:
A. M₁ + V₁ = M₂ + V₂
B. ✅✅ M₁V₁ = M₂V₂
C. PV = nRT
D. K = Q
Answer: ✅✅ B
Rationale: Moles of solute remain constant during dilution.
9. What is the main assumption in stoichiometry calculations?
A. Reactions are reversible
B. ✅✅ Reactants are completely consumed based on balanced equations
C. Temperature is irrelevant
D. Volume is always constant
Answer: ✅✅ B
Rationale: Stoichiometry assumes ideal complete reaction conversion.
Thermochemistry Review
10. Exothermic reactions:
A. Absorb energy
B. ✅✅ Release energy as heat
C. Require no energy change
D. Always nonspontaneous
Answer: ✅✅ B
Rationale: Heat is released to surroundings (ΔH < 0).
11. Endothermic reactions:
2026 CHEM 103 (General Chemistry)
Module 6 Practice Exam 100 Questions
and Answers with Rationales
Gas Laws & Molecular Behavior
1. Which gas law relates pressure and volume at constant temperature?
A. Charles’s Law
B. ✅✅ Boyle’s Law
C. Avogadro’s Law
D. Hess’s Law
Answer: ✅✅ B
Rationale: Boyle’s Law states pressure is inversely proportional to volume when temperature is
constant.
2. If the pressure of a gas increases while temperature remains constant, the
volume will:
A. Increase
B. ✅✅ Decrease
C. Stay constant
D. Become zero
Answer: ✅✅ B
Rationale: Boyle’s Law (P↑ → V↓).
3. Which equation correctly represents the Ideal Gas Law?
A. PV = nRT²
B. P/V = nRT
C. ✅✅ PV = nRT
D. Pn = RT
, CHEM 103 (General Chemistry) Module 6
Answer: ✅✅ C
Rationale: The ideal gas law relates pressure, volume, moles, and temperature.
4. A gas sample contains 2.0 mol at 300 K and 1 atm. What happens if
temperature increases at constant pressure?
V1T1=V2T2\frac{V_1}{T_1} = \frac{V_2}{T_2}T1V1=T2V2
V1T1=12300=V2T2=18450\frac{V_1}{T_1}=\frac{12}{300}=\frac{V_2}{T_2}=\frac{18}{45
0}T1V1=30012=T2V2=45018
V1V_1V1
L
T1T_1T1
K
V2V_2V2
L
T2T_2T2
K
State 1: 300 K, 12 LState 2: 450 K, 18 L
A. Volume decreases
B. Pressure increases
C. ✅✅ Volume increases
D. Moles decrease
Answer: ✅✅ C
Rationale: Charles’s Law: volume is directly proportional to temperature.
5. Which condition causes real gases to deviate most from ideal behavior?
A. High temperature, low pressure
B. ✅✅ Low temperature, high pressure
C. High temperature, high volume
D. Low pressure, high temperature
, CHEM 103 (General Chemistry) Module 6
Answer: ✅✅ B
Rationale: Particle interactions become significant under low T and high P.
Stoichiometry & Molarity
6. Molarity is defined as:
M=nVM = \frac{n}{V}M=Vn
M=1.2 mol0.8 L=1.5 mol/LM=\frac{1.2\,\mathrm{mol}}{0.8\,\mathrm{L}}=1.5\,\mathrm{mol/
L}M=0.8L1.2mol=1.5mol/L
nnn
mol
VVV
L
A. grams per mole
B. liters per mole
C. ✅✅ moles per liter of solution
D. moles per kilogram
Answer: ✅✅ C
Rationale: Molarity measures concentration in mol/L.
7. How many moles are in 2.0 L of a 0.50 M solution?
A. 0.10 mol
B. 0.50 mol
C. ✅✅ 1.0 mol
D. 2.5 mol
Answer: ✅✅ C
Rationale:
n=MV=(0.50)(2.0)=1.0 moln = MV = (0.50)(2.0)=1.0\text{ mol}n=MV=(0.50)(2.0)=1.0 mol
, CHEM 103 (General Chemistry) Module 6
8. Dilution equation is expressed as:
A. M₁ + V₁ = M₂ + V₂
B. ✅✅ M₁V₁ = M₂V₂
C. PV = nRT
D. K = Q
Answer: ✅✅ B
Rationale: Moles of solute remain constant during dilution.
9. What is the main assumption in stoichiometry calculations?
A. Reactions are reversible
B. ✅✅ Reactants are completely consumed based on balanced equations
C. Temperature is irrelevant
D. Volume is always constant
Answer: ✅✅ B
Rationale: Stoichiometry assumes ideal complete reaction conversion.
Thermochemistry Review
10. Exothermic reactions:
A. Absorb energy
B. ✅✅ Release energy as heat
C. Require no energy change
D. Always nonspontaneous
Answer: ✅✅ B
Rationale: Heat is released to surroundings (ΔH < 0).
11. Endothermic reactions:
