CHEM 121 Module 6 | Foundations of General Chemistry
w/Lab Exam Q&A | Portage Learning
These are original practice questions written for study. They cover common CHEM 121
Module 6 | Thermochemistry topics: energy, enthalpy, calorimetry, Hess’s law, heats of
formation, bond energies, phase changes, fuels and nutrition, and clinical applications.
Question 1:
Which of the following is the SI unit of energy?
A. Joule
B. Calorie
C. Kelvin
D. Watt
Correct answer: A
Rationale: The SI unit of energy is the joule (J).
Question 2:
How many joules are in 1 calorie?
A. 1.0 J
B. 4.184 J
C. 10.0 J
D. 1000 J
Correct answer: B
Rationale: 1 cal = 4.184 J.
Question 3:
In thermochemistry, the system is best defined as:
A. The entire universe
B. The part of the universe being studied
C. Only the container
D. Only the surroundings
Correct answer: B
Rationale: The system is the specific part of the universe under study.
,Question 4:
Which of the following is a state function?
A. Heat
B. Work
C. Enthalpy
D. Path length
Correct answer: C
Rationale: Enthalpy depends only on the current state, not the path.
Question 5:
Which of the following is NOT a state function?
A. Internal energy
B. Enthalpy
C. Entropy
D. Work
Correct answer: D
Rationale: Work depends on the path taken, so it is not a state function.
Question 6:
The first law of thermodynamics states that:
A. Energy can be created
B. Energy can be destroyed
C. Energy is conserved
D. Entropy always decreases
Correct answer: C
Rationale: Energy cannot be created or destroyed, only transferred or transformed.
Question 7:
If a system absorbs heat and has work done on it, its internal energy:
A. Increases
B. Decreases
C. Remains exactly zero
D. Cannot change
Correct answer: A
Rationale: Both heat absorbed and work done on the system increase internal energy.
, Question 8:
In an exothermic process, heat is:
A. Absorbed by the system
B. Released by the system
C. Not transferred
D. Converted to mass
Correct answer: B
Rationale: Exothermic processes release heat to the surroundings.
Question 9:
In an endothermic process, the sign of q is:
A. Negative
B. Positive
C. Zero
D. Undefined
Correct answer: B
Rationale: Endothermic processes absorb heat, so q is positive.
Question 10:
For an exothermic reaction, ΔH is:
A. Positive
B. Negative
C. Zero
D. Always equal to zero
Correct answer: B
Rationale: Exothermic reactions release heat and have negative ΔH.
Question 11:
Which process is endothermic?
A. Combustion of methane
B. Freezing water
C. Melting ice
D. Condensation of steam
Correct answer: C
Rationale: Melting ice absorbs heat, so it is endothermic.
w/Lab Exam Q&A | Portage Learning
These are original practice questions written for study. They cover common CHEM 121
Module 6 | Thermochemistry topics: energy, enthalpy, calorimetry, Hess’s law, heats of
formation, bond energies, phase changes, fuels and nutrition, and clinical applications.
Question 1:
Which of the following is the SI unit of energy?
A. Joule
B. Calorie
C. Kelvin
D. Watt
Correct answer: A
Rationale: The SI unit of energy is the joule (J).
Question 2:
How many joules are in 1 calorie?
A. 1.0 J
B. 4.184 J
C. 10.0 J
D. 1000 J
Correct answer: B
Rationale: 1 cal = 4.184 J.
Question 3:
In thermochemistry, the system is best defined as:
A. The entire universe
B. The part of the universe being studied
C. Only the container
D. Only the surroundings
Correct answer: B
Rationale: The system is the specific part of the universe under study.
,Question 4:
Which of the following is a state function?
A. Heat
B. Work
C. Enthalpy
D. Path length
Correct answer: C
Rationale: Enthalpy depends only on the current state, not the path.
Question 5:
Which of the following is NOT a state function?
A. Internal energy
B. Enthalpy
C. Entropy
D. Work
Correct answer: D
Rationale: Work depends on the path taken, so it is not a state function.
Question 6:
The first law of thermodynamics states that:
A. Energy can be created
B. Energy can be destroyed
C. Energy is conserved
D. Entropy always decreases
Correct answer: C
Rationale: Energy cannot be created or destroyed, only transferred or transformed.
Question 7:
If a system absorbs heat and has work done on it, its internal energy:
A. Increases
B. Decreases
C. Remains exactly zero
D. Cannot change
Correct answer: A
Rationale: Both heat absorbed and work done on the system increase internal energy.
, Question 8:
In an exothermic process, heat is:
A. Absorbed by the system
B. Released by the system
C. Not transferred
D. Converted to mass
Correct answer: B
Rationale: Exothermic processes release heat to the surroundings.
Question 9:
In an endothermic process, the sign of q is:
A. Negative
B. Positive
C. Zero
D. Undefined
Correct answer: B
Rationale: Endothermic processes absorb heat, so q is positive.
Question 10:
For an exothermic reaction, ΔH is:
A. Positive
B. Negative
C. Zero
D. Always equal to zero
Correct answer: B
Rationale: Exothermic reactions release heat and have negative ΔH.
Question 11:
Which process is endothermic?
A. Combustion of methane
B. Freezing water
C. Melting ice
D. Condensation of steam
Correct answer: C
Rationale: Melting ice absorbs heat, so it is endothermic.
