Lab: Portage Learning CHEM 103 General
Chemistry I Module 3 Lab Exam | 2026/2027
Updated Edition with 100% Verified Answers
Question 1
1. What 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 ΔH is positive
Answer
Answer B: A reaction that releases heat into the surroundings
Rationale
Exothermic reactions release energy, usually as heat, and have a negative enthalpy change (ΔH < 0) .
Question 2
2. According to Boyle's Law, what happens to the volume of a gas when the pressure is doubled
at constant temperature?
A) The volume doubles
B) The volume is reduced by half
C) The volume stays the same
D) The volume quadruples
Answer
Answer B: The volume is reduced by half
,Rationale
Boyle's Law states pressure and volume are inversely proportional (P₁V₁ = P₂V₂). Doubling pressure
halves the volume .
Question 3
3. What is the standard molar volume of an ideal gas at STP?
A) 1.00 L
B) 22.4 L
C) 24.5 L
D) 0.0821 L
Answer
Answer B: 22.4 L
Rationale
At STP (0°C and 1 atm), one mole of any ideal gas occupies 22.4 liters .
Question 4
4. Which gas law describes the relationship between 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
Answer
Answer B: Charles's Law
Rationale
,Charles's Law states volume is directly proportional to absolute temperature (V₁/T₁ = V₂/T₂) at constant
pressure .
Question 5
5. What is the specific heat equation used to calculate heat transfer?
A) q = m × c × ΔT
B) q = m × c × ΔT
C) q = m × ΔT
D) q = c × ΔT
Answer
Answer A: q = m × c × ΔT
Rationale
The heat equation q = mcΔT relates heat (q) to mass (m), specific heat (c), and temperature change
(ΔT).
Question 6
6. In the Ideal Gas Law equation PV = nRT, what does the variable 'n' represent?
A) Number of particles
B) Number of moles
C) Number of grams
D) Number of atoms
Answer
Answer B: Number of moles
Rationale
In the Ideal Gas Law, 'n' represents the amount of substance in moles .
, Question 7
7. Calculate the heat required to raise the temperature of 10.0 g of water by 5.0°C. (c of water =
4.184 J/g°C)
A) 41.84 J
B) 209.2 J
C) 50.0 J
D) 4.184 J
Answer
Answer B: 209.2 J
Rationale
q = m × c × ΔT = 10.0 g × 4.184 J/g°C × 5.0°C = 209.2 J .
Question 8
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
Answer
Answer B: Pressure increases
Rationale
Gay-Lussac's Law states pressure is directly proportional to absolute temperature at constant volume
(P₁/T₁ = P₂/T₂) .
Question 9
Chemistry I Module 3 Lab Exam | 2026/2027
Updated Edition with 100% Verified Answers
Question 1
1. What 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 ΔH is positive
Answer
Answer B: A reaction that releases heat into the surroundings
Rationale
Exothermic reactions release energy, usually as heat, and have a negative enthalpy change (ΔH < 0) .
Question 2
2. According to Boyle's Law, what happens to the volume of a gas when the pressure is doubled
at constant temperature?
A) The volume doubles
B) The volume is reduced by half
C) The volume stays the same
D) The volume quadruples
Answer
Answer B: The volume is reduced by half
,Rationale
Boyle's Law states pressure and volume are inversely proportional (P₁V₁ = P₂V₂). Doubling pressure
halves the volume .
Question 3
3. What is the standard molar volume of an ideal gas at STP?
A) 1.00 L
B) 22.4 L
C) 24.5 L
D) 0.0821 L
Answer
Answer B: 22.4 L
Rationale
At STP (0°C and 1 atm), one mole of any ideal gas occupies 22.4 liters .
Question 4
4. Which gas law describes the relationship between 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
Answer
Answer B: Charles's Law
Rationale
,Charles's Law states volume is directly proportional to absolute temperature (V₁/T₁ = V₂/T₂) at constant
pressure .
Question 5
5. What is the specific heat equation used to calculate heat transfer?
A) q = m × c × ΔT
B) q = m × c × ΔT
C) q = m × ΔT
D) q = c × ΔT
Answer
Answer A: q = m × c × ΔT
Rationale
The heat equation q = mcΔT relates heat (q) to mass (m), specific heat (c), and temperature change
(ΔT).
Question 6
6. In the Ideal Gas Law equation PV = nRT, what does the variable 'n' represent?
A) Number of particles
B) Number of moles
C) Number of grams
D) Number of atoms
Answer
Answer B: Number of moles
Rationale
In the Ideal Gas Law, 'n' represents the amount of substance in moles .
, Question 7
7. Calculate the heat required to raise the temperature of 10.0 g of water by 5.0°C. (c of water =
4.184 J/g°C)
A) 41.84 J
B) 209.2 J
C) 50.0 J
D) 4.184 J
Answer
Answer B: 209.2 J
Rationale
q = m × c × ΔT = 10.0 g × 4.184 J/g°C × 5.0°C = 209.2 J .
Question 8
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
Answer
Answer B: Pressure increases
Rationale
Gay-Lussac's Law states pressure is directly proportional to absolute temperature at constant volume
(P₁/T₁ = P₂/T₂) .
Question 9
