Chapter 19 - Equilibrium Flashcards

The equilibrium constant - part 2, The equilibrium constant, Controlling the position of equilibrium.

1
Q

How are the units of Kc worked out?

A

Substitute units into the expression

Cancel common units

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a homogeneous equilibrium?

A

Equilibrium species all have the same state.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a heterogeneous equilibrium?

A

Equilibrium species that have different states.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

In a heterogeneous equilibrium, what is discounted in the expression for Kc?

A

Any species that are not as a gas or in solution.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a mole fraction?

A

The proportion of the volume of a gas to the total volume of gases in the mixture.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the partial pressure?

A

The contribution that the gas makes towards the total pressure P.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How is a mole fraction calculated?

A

Mole fraction χ(A) = n(A)/n(total)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How is partial pressure calculated?

A
p(A) = mole fraction x total pressure P
p(A) = χ(A) x P
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the way to check the partial pressures are correct?

A

Sum of the partial pressures equals the total pressure.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

With the equilibrium H(2) + I(2) 2HI, what is the expression for Kp?

A

Kp = p(HI)^2 / p(H(2)) x p(I(2))

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does the magnitude of an equilibrium constant represent?

A

The extent of an equilibrium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What would K=1, K=100 and K=0.01 represent?

A

K=1: equilibrium halfway between reactants and products
K=100: equilibrium in favour of products
K=0.01: equilibrium in favour of reactants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the effect on K when the temperature is increased and the forward reaction is exothermic?

A

Equilibrium constant decreases

Equilibrium shifts to reactant side

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the effect on K when the temperature is increased and the forward reaction is endothermic?

A

Equilibrium constant increases

Equilibrium shifts to product side

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What effect does increasing pressure have on a reaction with fewer moles of gaseous products than reactants?

A

Products increase
Reactants decrease
Equilibrium shifts to right

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What effect does increasing pressure have on a reaction with more moles of gaseous products than reactants?

A

Products decrease
Reactants increase
Equilibrium shifts to left

17
Q

What effect does increasing pressure have on a reaction with the same number of moles of gaseous products and reactants?

A

No change

Equilibrium stays the same

18
Q

What is the effect of a catalyst on the equilibrium constant?

A

Catalysts affect the rate but not the equilibrium position.

Equilibrium is reached faster but position does not change.