CHEM 103 (General Chemistry) Module 3
2026 CHEM 103 (General Chemistry)
Module 3 Practice Exam 100 Questions
and Answers with Rationales
Questions 1–25
Fundamentals of Thermochemistry, Energy, Calorimetry & Reaction Rates
1. Which statement correctly defines thermochemistry?
A. Study of atomic structure
B. Study of gases only
C. ✅✅ Study of heat changes accompanying chemical and physical processes
D. Study of equilibrium only
Answer: ✅✅ C
Rationale:
Thermochemistry examines the transfer of heat during chemical reactions and physical changes.
2. Heat is best defined as:
A. Stored energy
B. ✅✅ Energy transferred because of a temperature difference
C. Total molecular motion
D. Potential energy
Answer: ✅✅ B
Rationale:
Heat is energy in transit between systems due to temperature differences.
, CHEM 103 (General Chemistry) Module 3
3. Which quantity is measured in joules (J)?
A. Density
B. Pressure
C. ✅✅ Energy
D. Molarity
Answer: ✅✅ C
Rationale:
The SI unit for energy is the joule (J).
4. Which process is exothermic?
A. Melting ice
B. Boiling water
C. ✅✅ Combustion of methane
D. Sublimation of dry ice
Answer: ✅✅ C
Rationale:
Combustion releases heat to the surroundings.
5. An endothermic reaction:
A. Releases heat
B. ✅✅ Absorbs heat from the surroundings
C. Has negative ΔH
D. Always occurs spontaneously
Answer: ✅✅ B
, CHEM 103 (General Chemistry) Module 3
Rationale:
Endothermic processes require energy input and have positive enthalpy changes.
6. Which sign represents an exothermic enthalpy change?
A. Positive
B. ✅✅ Negative
C. Zero
D. Undefined
Answer: ✅✅ B
Rationale:
Exothermic reactions have negative ΔH because energy leaves the system.
7. Which quantity depends only on the initial and final states of a system?
A. Work
B. Heat
C. ✅✅ Enthalpy
D. Temperature
Answer: ✅✅ C
Rationale:
Enthalpy is a state function.
8. Which law states that energy cannot be created or destroyed?
A. Boyle's Law
B. ✅✅ First Law of Thermodynamics
, CHEM 103 (General Chemistry) Module 3
C. Charles's Law
D. Hess's Law
Answer: ✅✅ B
Rationale:
The First Law expresses conservation of energy.
9. Specific heat capacity is defined as:
A. Heat required to melt 1 g
B. ✅✅ Heat required to raise 1 g of a substance by 1°C
C. Heat required to boil water
D. Total heat released
Answer: ✅✅ B
Rationale:
Specific heat measures resistance to temperature change.
10. Water has a relatively high specific heat, meaning it:
A. Cools rapidly
B. ✅✅ Resists temperature change
C. Conducts electricity well
D. Boils at low temperature
Answer: ✅✅ B
Rationale:
Water can absorb or release large amounts of heat with only small temperature changes.
2026 CHEM 103 (General Chemistry)
Module 3 Practice Exam 100 Questions
and Answers with Rationales
Questions 1–25
Fundamentals of Thermochemistry, Energy, Calorimetry & Reaction Rates
1. Which statement correctly defines thermochemistry?
A. Study of atomic structure
B. Study of gases only
C. ✅✅ Study of heat changes accompanying chemical and physical processes
D. Study of equilibrium only
Answer: ✅✅ C
Rationale:
Thermochemistry examines the transfer of heat during chemical reactions and physical changes.
2. Heat is best defined as:
A. Stored energy
B. ✅✅ Energy transferred because of a temperature difference
C. Total molecular motion
D. Potential energy
Answer: ✅✅ B
Rationale:
Heat is energy in transit between systems due to temperature differences.
, CHEM 103 (General Chemistry) Module 3
3. Which quantity is measured in joules (J)?
A. Density
B. Pressure
C. ✅✅ Energy
D. Molarity
Answer: ✅✅ C
Rationale:
The SI unit for energy is the joule (J).
4. Which process is exothermic?
A. Melting ice
B. Boiling water
C. ✅✅ Combustion of methane
D. Sublimation of dry ice
Answer: ✅✅ C
Rationale:
Combustion releases heat to the surroundings.
5. An endothermic reaction:
A. Releases heat
B. ✅✅ Absorbs heat from the surroundings
C. Has negative ΔH
D. Always occurs spontaneously
Answer: ✅✅ B
, CHEM 103 (General Chemistry) Module 3
Rationale:
Endothermic processes require energy input and have positive enthalpy changes.
6. Which sign represents an exothermic enthalpy change?
A. Positive
B. ✅✅ Negative
C. Zero
D. Undefined
Answer: ✅✅ B
Rationale:
Exothermic reactions have negative ΔH because energy leaves the system.
7. Which quantity depends only on the initial and final states of a system?
A. Work
B. Heat
C. ✅✅ Enthalpy
D. Temperature
Answer: ✅✅ C
Rationale:
Enthalpy is a state function.
8. Which law states that energy cannot be created or destroyed?
A. Boyle's Law
B. ✅✅ First Law of Thermodynamics
, CHEM 103 (General Chemistry) Module 3
C. Charles's Law
D. Hess's Law
Answer: ✅✅ B
Rationale:
The First Law expresses conservation of energy.
9. Specific heat capacity is defined as:
A. Heat required to melt 1 g
B. ✅✅ Heat required to raise 1 g of a substance by 1°C
C. Heat required to boil water
D. Total heat released
Answer: ✅✅ B
Rationale:
Specific heat measures resistance to temperature change.
10. Water has a relatively high specific heat, meaning it:
A. Cools rapidly
B. ✅✅ Resists temperature change
C. Conducts electricity well
D. Boils at low temperature
Answer: ✅✅ B
Rationale:
Water can absorb or release large amounts of heat with only small temperature changes.
