Chapter 9: Chemical Equilibrium

1

Removal of products shifts equilibrium toward:

A Reactants B Products C No change D Stopping reaction

2

Equilibrium constant for a given reaction is:

A Always changing B Constant at fixed temperature C Affected by catalyst D Affected by pressure

3

Ibrahim is learning about the conditions for equilibrium. He understands that temperature can affect the position of equilibrium. According to Le Chatelier's principle, how does an increase in temperature affect an endothermic reaction?

A It shifts the equilibrium to the left B It shifts the equilibrium to the right C It has no effect D It stops the reaction

4

According to the law of mass action, the rate of reaction is proportional to:

A Temperature only B Pressure only C Product of active masses of reactants D Volume of container

5

Bilal is studying dynamic equilibrium. He understands that at equilibrium, the rate of the forward reaction equals the rate of the reverse reaction. What is the state of the concentrations of reactants and products at equilibrium?

A They are equal B They are constant but not necessarily equal C They are zero D They are continuously changing

6

If the value of equilibrium constant is very large, the reaction favors:

A Reactants B Products C Both equally D Neither

7

Equilibrium constant is a measure of:

A Rate of reaction B Extent of reaction C Speed of reaction D Time of reaction

8

Aisha is learning about dynamic equilibrium. She understands that at equilibrium, the system is in a state of balance. Which of the following statements is true about dynamic equilibrium?

A It occurs only in irreversible reactions B It occurs only in reversible reactions C It occurs in all reactions D It occurs only in biological systems

9

Yara is learning about Le Chatelier's principle. She knows that adding a catalyst to a system at equilibrium will not shift the equilibrium. Why is a catalyst used in industrial processes then?

A To increase the yield of products B To speed up the attainment of equilibrium C To shift the equilibrium to the right D To shift the equilibrium to the left

10

Waleed is learning about the conditions for equilibrium. He knows that the reaction must be reversible and the system must be closed. Which of the following is also required for equilibrium?

A Constant temperature B Constant pressure C Equal concentrations of reactants and products D Both A and B

11

Qasim is learning about dynamic equilibrium. He understands that at equilibrium, the reaction has not stopped. Which of the following statements best describes dynamic equilibrium?

A The forward reaction is faster than the reverse reaction B The reverse reaction is faster than the forward reaction C Both forward and reverse reactions occur at the same rate D Neither reaction occurs

12

Chemical equilibrium is achieved when:

A Reaction stops completely B Concentration of reactants becomes zero C Forward and reverse reaction rates are equal D Products stop reacting

13

Julia is studying dynamic equilibrium. She learns that at equilibrium, the reaction has not ceased. Which of the following statements is true at equilibrium?

A The forward reaction is faster B The reverse reaction is faster C Both reactions have stopped D Both reactions occur at the same rate

14

Ahmed is learning about reversible reactions in his chemistry class. His teacher explains that in a reversible reaction, the products can react to form the original reactants. Which of the following represents a reversible reaction?

A A + B → C + D B A + B ⇌ C + D C A + B → C D C + D → A + B

15

Which condition is necessary for equilibrium to be established?

A Open system B Closed system C High temperature only D Low pressure only

16

Hina is studying chemical equilibrium. She learns that the equilibrium constant (K) is temperature-dependent. What happens to K for an exothermic reaction when the temperature is decreased?

A K increases B K decreases C K remains the same D K becomes infinite

17

Which factor does NOT affect the position of equilibrium?

A Temperature B Pressure C Concentration D Catalyst

18

Equilibrium constant is independent of:

A Temperature B Catalyst C Nature of reaction D Stoichiometry

19

Tina is studying the effect of pressure on equilibrium. She knows that for a reaction with more moles of gas on the reactant side, increasing pressure will shift the equilibrium to:

A The left B The right C No effect D Both sides equally

20

The equilibrium constant is represented by:

A K B Keq C Ka D Kb

21

Paula is studying chemical equilibrium. She understands that equilibrium can be affected by changes in concentration, temperature, and pressure. What is the principle that predicts the direction of the shift?

A The law of conservation of mass B Le Chatelier's principle C The law of definite proportions D The law of multiple proportions

22

Ethan is learning about dynamic equilibrium. He knows that equilibrium can be established in a closed system. Which of the following is an example of a closed system?

A A sealed flask containing water and ice B An open beaker C A river D A human body

23

In dynamic equilibrium:

A No reaction occurs B Only forward reaction occurs C Both reactions continue at equal rates D Only reverse reaction occurs

24

A catalyst affects equilibrium by:

A Changing equilibrium constant B Shifting equilibrium C Increasing rate of both reactions D Stopping reverse reaction

25

Xia is studying the conditions for equilibrium. She learns that equilibrium is a dynamic process. Which of the following is an example of a system at dynamic equilibrium?

A A sealed container of water and ice at 0°C B A burning candle C A piece of iron rusting D A glass of soda losing its fizz