2026 UPDATED QUESTIONS DOWNLOAD
Portage Learning CHEM 103 General Chemistry I: Module 3 EXAM BANK (200+ Q&A) |
Stoichiometry, Gas Laws & Thermochemistry | Full Study Guide & Verified Rationales |
2025/2026 Edition
Ace your Portage Learning CHEM 103 Module 3 Exam with this comprehensive 200-question
master bank, specifically updated for the 2025/2026 academic year. This study guide provides
detailed, step-by-step rationales in italics for every question, covering high-yield topics such as
Stoichiometry, Ideal Gas Laws, and Thermochemical Enthalpy calculations. Designed to mirror
the actual exam format, this resource ensures you master complex calorimetry and gas mixture
problems for a guaranteed pass on your first attempt.
1. Which of the following is the correct definition of an exothermic reaction?
A. A reaction that absorbs heat from the surroundings.
B. A reaction that releases heat into the surroundings.
C. A reaction where the temperature of the system decreases.
D. A reaction where
is positive.
Correct Answer: B
Rationale: Exothermic reactions release energy, usually in the form of heat, causing the
temperature of the surroundings to rise. In these reactions, the enthalpy change (
) is always negative.
2. According to Boyle’s Law, if the pressure of a gas is doubled at a constant
temperature, what happens to the volume?
A. The volume doubles.
B. The volume remains the same.
C. The volume is reduced by half.
D. The volume increases fourfold.
Correct Answer: C
Rationale: Boyle’s Law states that pressure and volume are inversely proportional (
). If pressure increases, volume must decrease by the same factor.
3. What is the standard molar volume of an ideal gas at STP (Standard Temperature and
Pressure)?
, 2026 UPDATED QUESTIONS DOWNLOAD
A. 1.00 L
B. 22.4 L
C. 24.5 L
D. 0.0821 L
Correct Answer: B
Rationale: At STP (0°C and 1 atm), one mole of any ideal gas occupies exactly 22.4 liters of
space.
4. In the Ideal Gas Law equation (
), what does the variable 'n' represent?
A. Number of particles
B. Number of moles
C. Net pressure
D. Normal temperature
Correct Answer: B
Rationale: The variable 'n' represents the amount of substance in moles. This allows the
equation to relate physical properties to the quantity of gas present.
5. Which of the following conditions defines "Standard Temperature" for gas law
calculations?
A. 25°C
B. 100°C
C. 0°C (273.15 K)
D. 37°C
Correct Answer: C
Rationale: For gas laws, standard temperature is defined as 0 degrees Celsius, which must be
converted to 273.15 Kelvin for use in formulas.
6. A sample of gas has a volume of 4.0 L at 2.0 atm. If the pressure is increased to 4.0
atm at constant temperature, what is the new volume?
A. 1.0 L
B. 2.0 L
C. 8.0 L
D. 16.0 L
Correct Answer: B
Rationale: Using
: (2.0 atm)(4.0 L) = (4.0 atm)(V2). Solving for V2 gives 2.0 L. This demonstrates the inverse
relationship of Boyle's Law.
, 2026 UPDATED QUESTIONS DOWNLOAD
7. Which gas law describes the relationship between the volume and temperature of a
gas at constant pressure?
A. Boyle’s Law
B. Charles’s Law
C. Gay-Lussac’s Law
D. Dalton’s Law
Correct Answer: B
Rationale: Charles’s Law states that the volume of a gas is directly proportional to its absolute
temperature (
) when pressure is held constant.
8. What happens to the pressure of a gas in a rigid container if the temperature is
increased?
A. Pressure decreases.
B. Pressure increases.
C. Pressure remains constant.
D. Volume increases.
Correct Answer: B
Rationale: According to Gay-Lussac’s Law, pressure and temperature are directly proportional
in a fixed volume. Increasing temperature increases the kinetic energy of particles, leading to
more frequent and forceful collisions.
9. In a thermochemical equation, if
, the reaction is:
A. Exothermic
B. Endothermic
C. Spontaneous
D. Combustion
Correct Answer: B
Rationale: A positive enthalpy (
) indicates that the system has absorbed energy from the surroundings, which defines an
endothermic process.
10. Which of the following is the correct value for the Ideal Gas Constant (R) when using
units of atm, L, mol, and K?
, 2026 UPDATED QUESTIONS DOWNLOAD
A. 8.314
B. 6.022
C. 0.0821
D. 1.013
Correct Answer: C
Rationale: The constant 0.0821
is used specifically when pressure is in atmospheres and volume is in liters.
11. Dalton’s Law of Partial Pressures states that the total pressure of a gas mixture is:
A. The average of all individual pressures.
B. The product of all individual pressures.
C. The sum of the partial pressures of all component gases.
D. Equal to the pressure of the most abundant gas.
Correct Answer: C
Rationale: Dalton's Law (
) explains that each gas in a mixture exerts pressure independently of the others.
12. The specific heat of water is 4.184
. How much heat is required to raise the temperature of 10g of water by 5°C?
A. 41.84 J
B. 209.2 J
C. 50.0 J
D. 4.184 J
Correct Answer: B
Rationale: Using
Portage Learning CHEM 103 General Chemistry I: Module 3 EXAM BANK (200+ Q&A) |
Stoichiometry, Gas Laws & Thermochemistry | Full Study Guide & Verified Rationales |
2025/2026 Edition
Ace your Portage Learning CHEM 103 Module 3 Exam with this comprehensive 200-question
master bank, specifically updated for the 2025/2026 academic year. This study guide provides
detailed, step-by-step rationales in italics for every question, covering high-yield topics such as
Stoichiometry, Ideal Gas Laws, and Thermochemical Enthalpy calculations. Designed to mirror
the actual exam format, this resource ensures you master complex calorimetry and gas mixture
problems for a guaranteed pass on your first attempt.
1. Which of the following is the correct definition of an exothermic reaction?
A. A reaction that absorbs heat from the surroundings.
B. A reaction that releases heat into the surroundings.
C. A reaction where the temperature of the system decreases.
D. A reaction where
is positive.
Correct Answer: B
Rationale: Exothermic reactions release energy, usually in the form of heat, causing the
temperature of the surroundings to rise. In these reactions, the enthalpy change (
) is always negative.
2. According to Boyle’s Law, if the pressure of a gas is doubled at a constant
temperature, what happens to the volume?
A. The volume doubles.
B. The volume remains the same.
C. The volume is reduced by half.
D. The volume increases fourfold.
Correct Answer: C
Rationale: Boyle’s Law states that pressure and volume are inversely proportional (
). If pressure increases, volume must decrease by the same factor.
3. What is the standard molar volume of an ideal gas at STP (Standard Temperature and
Pressure)?
, 2026 UPDATED QUESTIONS DOWNLOAD
A. 1.00 L
B. 22.4 L
C. 24.5 L
D. 0.0821 L
Correct Answer: B
Rationale: At STP (0°C and 1 atm), one mole of any ideal gas occupies exactly 22.4 liters of
space.
4. In the Ideal Gas Law equation (
), what does the variable 'n' represent?
A. Number of particles
B. Number of moles
C. Net pressure
D. Normal temperature
Correct Answer: B
Rationale: The variable 'n' represents the amount of substance in moles. This allows the
equation to relate physical properties to the quantity of gas present.
5. Which of the following conditions defines "Standard Temperature" for gas law
calculations?
A. 25°C
B. 100°C
C. 0°C (273.15 K)
D. 37°C
Correct Answer: C
Rationale: For gas laws, standard temperature is defined as 0 degrees Celsius, which must be
converted to 273.15 Kelvin for use in formulas.
6. A sample of gas has a volume of 4.0 L at 2.0 atm. If the pressure is increased to 4.0
atm at constant temperature, what is the new volume?
A. 1.0 L
B. 2.0 L
C. 8.0 L
D. 16.0 L
Correct Answer: B
Rationale: Using
: (2.0 atm)(4.0 L) = (4.0 atm)(V2). Solving for V2 gives 2.0 L. This demonstrates the inverse
relationship of Boyle's Law.
, 2026 UPDATED QUESTIONS DOWNLOAD
7. Which gas law describes the relationship between the volume and temperature of a
gas at constant pressure?
A. Boyle’s Law
B. Charles’s Law
C. Gay-Lussac’s Law
D. Dalton’s Law
Correct Answer: B
Rationale: Charles’s Law states that the volume of a gas is directly proportional to its absolute
temperature (
) when pressure is held constant.
8. What happens to the pressure of a gas in a rigid container if the temperature is
increased?
A. Pressure decreases.
B. Pressure increases.
C. Pressure remains constant.
D. Volume increases.
Correct Answer: B
Rationale: According to Gay-Lussac’s Law, pressure and temperature are directly proportional
in a fixed volume. Increasing temperature increases the kinetic energy of particles, leading to
more frequent and forceful collisions.
9. In a thermochemical equation, if
, the reaction is:
A. Exothermic
B. Endothermic
C. Spontaneous
D. Combustion
Correct Answer: B
Rationale: A positive enthalpy (
) indicates that the system has absorbed energy from the surroundings, which defines an
endothermic process.
10. Which of the following is the correct value for the Ideal Gas Constant (R) when using
units of atm, L, mol, and K?
, 2026 UPDATED QUESTIONS DOWNLOAD
A. 8.314
B. 6.022
C. 0.0821
D. 1.013
Correct Answer: C
Rationale: The constant 0.0821
is used specifically when pressure is in atmospheres and volume is in liters.
11. Dalton’s Law of Partial Pressures states that the total pressure of a gas mixture is:
A. The average of all individual pressures.
B. The product of all individual pressures.
C. The sum of the partial pressures of all component gases.
D. Equal to the pressure of the most abundant gas.
Correct Answer: C
Rationale: Dalton's Law (
) explains that each gas in a mixture exerts pressure independently of the others.
12. The specific heat of water is 4.184
. How much heat is required to raise the temperature of 10g of water by 5°C?
A. 41.84 J
B. 209.2 J
C. 50.0 J
D. 4.184 J
Correct Answer: B
Rationale: Using
