Chapter 7.1

Question 1

When is equilibrium reached?

Answer 1

When no further change appears to occur, and all concentrations remain constant

Question 2

Dynamic equilibrium

Answer 2

When concentrations of reactants and products remains the same and the rate of the forward reaction is equal to the rate of the reverse reaction

Question 3

Five characteristics of equilibrium state

Answer 3

The macroscopic properties are constant at equilibrium
In equilibrium the rate of forward reaction is equal to the rate of the reverse reaction
Equilibrium can only be attained in a closed system
All species in the equilibrium are present in the equilibrium reaction mixture
Equilibrium can be attained from either direction

Question 4

When is liquid vapor equilibrium reached?

Answer 4

When the rate of evaporation is equal to the rate of condensation

Question 5

True or false? Equilibrium implies that there are 50% products and 50% reactants

Answer 5

False. Concentrations do not have to be equal for equilibrium to be reached

Question 6

Le Chatelier’s principle

Answer 6

If a system at equilibrium is subjected to a change, the position of equilibrium will shift in order to minimize the effect of the change

Question 7

What does heating a reaction mixture do to equilibrium?

Answer 7

Shifts it in the endothermic direction

Question 8

What does cooling a reaction mixture do to equilibrium?

Answer 8

Shifts it in the exothermic reaction

Question 9

If a reaction involves a change in the number of gas molecules, increasing pressure moves the position of equilibrium in

Answer 9

the direction that gives a decrease in the number of gas molecules

Question 10

If the concentration of one of the species in an equilibrium mixture is increased, the position of equilibrium shifts

Answer 10

to the opposite side to reduce the concentration of this species

Question 11

Kc

Answer 11

Equilibrium constant

Question 12

True or false? Kc is constant for a particular reaction at a particular temperature

Answer 12

True

Question 13

What does the equilibrium constant do?

Answer 13

Provides information about how far a reaction proceeds at a particular temperature

Question 14

When equilibrium constant&raquo_space; 1,

Answer 14

Reaction proceeds almost totally towards the products

Question 15

When equilibrium constant &laquo_space;1,

Answer 15

the reaction hardly proceeds at all towards the products

Question 16

What is the only thing that affects the value of the equilibrium constant for a particular reaction?

Answer 16

Temperature

Question 17

For an exothermic reaction, as temperature is increased, the value of the equilibrium constant

Answer 17

decreases

Question 18

For an endothermic reaction, as the temperature is raised the value of the equilibrium constant

Answer 18

increases

Question 19

What does a catalyst do in terms of forward and reverse reactions?

Answer 19

Increases the rate of both equally

Question 20

Does the presence of a catalyst affect position of equilibrium or the value of the constant? What does it do?

Answer 20

No. It only reduces the time taken to reach equilibrium.

Question 21

Gives information about how far a reaction goes towards completion but gives no information about how quickly the reaction occurs

Answer 21

Equilibrium constant

Question 22

Indicates how quickly equilibrium is attained but provides no information whatsoever about the position of equilibrium and how far the reaction proceeds

Answer 22

Kinetic data, such as the rate constant