CHEM 104 MODULE 5 PRACTICE EXAM
QUESTIONS AND CORRECT ANSWERS
(VERIFIED ANSWERS) PLUS RATIONALES
2025
1. Which of the following will increase the rate of a chemical reaction?
A. Lowering the temperature
B. Decreasing the concentration of reactants
C. Adding a catalyst
D. Removing products as they form
Adding a catalyst lowers the activation energy required, increasing the reaction
rate.
2. What does the rate law express?
A. The equilibrium constant
B. The relationship between rate and reactant concentrations
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,C. The overall stoichiometry of the reaction
D. The amount of product formed over time
Rate law shows how the rate depends on the concentration of each reactant.
3. If a reaction is first order with respect to [A], what will happen to the rate if
[A] is doubled?
A. Rate stays the same
B. Rate doubles
C. Rate triples
D. Rate quadruples
In a first-order reaction, the rate is directly proportional to the concentration of A.
4. A reaction has the rate law: rate = k[A][B]^2. What is the overall order of
the reaction?
A. First
B. Second
C. Third
D. Fourth
Order is the sum of exponents: 1 (for A) + 2 (for B) = 3.
5. What is the unit of the rate constant (k) for a first-order reaction?
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, A. mol/L
B. L/mol·s
C. s⁻¹
D. mol/s
For first-order reactions, the unit of k is reciprocal time.
6. At equilibrium, which of the following is true?
A. Forward reaction stops
B. Reactants are completely used
C. Forward and reverse reaction rates are equal
D. Concentrations of products and reactants are equal
Equilibrium means the forward and reverse rates are equal, not the
concentrations.
7. What does a large value of the equilibrium constant (K) indicate?
A. The reaction is slow
B. Products are favored
C. Reactants are favored
D. The reaction is at equilibrium
A large K means the concentration of products is much higher than that of
reactants.
8. Which of the following changes will shift the equilibrium to the right?
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QUESTIONS AND CORRECT ANSWERS
(VERIFIED ANSWERS) PLUS RATIONALES
2025
1. Which of the following will increase the rate of a chemical reaction?
A. Lowering the temperature
B. Decreasing the concentration of reactants
C. Adding a catalyst
D. Removing products as they form
Adding a catalyst lowers the activation energy required, increasing the reaction
rate.
2. What does the rate law express?
A. The equilibrium constant
B. The relationship between rate and reactant concentrations
1|Page
,C. The overall stoichiometry of the reaction
D. The amount of product formed over time
Rate law shows how the rate depends on the concentration of each reactant.
3. If a reaction is first order with respect to [A], what will happen to the rate if
[A] is doubled?
A. Rate stays the same
B. Rate doubles
C. Rate triples
D. Rate quadruples
In a first-order reaction, the rate is directly proportional to the concentration of A.
4. A reaction has the rate law: rate = k[A][B]^2. What is the overall order of
the reaction?
A. First
B. Second
C. Third
D. Fourth
Order is the sum of exponents: 1 (for A) + 2 (for B) = 3.
5. What is the unit of the rate constant (k) for a first-order reaction?
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, A. mol/L
B. L/mol·s
C. s⁻¹
D. mol/s
For first-order reactions, the unit of k is reciprocal time.
6. At equilibrium, which of the following is true?
A. Forward reaction stops
B. Reactants are completely used
C. Forward and reverse reaction rates are equal
D. Concentrations of products and reactants are equal
Equilibrium means the forward and reverse rates are equal, not the
concentrations.
7. What does a large value of the equilibrium constant (K) indicate?
A. The reaction is slow
B. Products are favored
C. Reactants are favored
D. The reaction is at equilibrium
A large K means the concentration of products is much higher than that of
reactants.
8. Which of the following changes will shift the equilibrium to the right?
3|Page
