equilibrium constant

Question 1

what is Kᴄ

Answer 1

The equilibrium constant

Question 2

Define homogeneous equilibria

Answer 2

All the species of the equilibira have the same phase/ state

Question 3

Define hetrogeneous equilibria

Answer 3

The species of equilibria have different phases/states

Question 4

Some states left out of Kᴄ and Kᴘ equilibria, what states and why?

Answer 4

Species with solid and liquid states are left out of calculations as their concentrations are constant.

Question 5

What is Kᴘ

Answer 5

The equilibrium constant for partial pressures.

Question 6

Why does Kᴘ have a direct relatioship to Kᴄ?

Answer 6

Concentration and partial pressues are proportional.

Question 7

What is the equation for molar fraction?

Answer 7

Molar fraction =
Number of moles of ‘x’ /
total number of moles in gas mixture

Question 8

what is the equation for partial pressure

Answer 8

Partial pressure =
Molar fraction X total pressure

Question 9

What is the only condition that will cause the equilibrium constant to change?

Answer 9

Temperature

Question 10

Name two conditionas that do not cause a change in the equilibrium constant

Answer 10

Any two from:
- Concentration
- Pressure
- Catalyst

Question 11

If the forward reaction is exothermic what happens to the equilibrium constant if temperature increases?

Answer 11

The equilibrium constant will decrease, and shift towards the products.

Question 12

Describe what happens to the Kᴄ or Kᴘ value of an (exothermic forward) reaction when the temperature increases

Answer 12

A new Kᴄ or Kᴘ value is made (smaller than before), an the system is therefore no longer in equilibrium. The product’s partial pressure or concentration must decrease and the reactants concentration or pressure must increase until the new Kᴄ or Kᴘ values are met. The system will then be in the new equilibrium.

Question 13

Describe what happens to the Kᴄ or Kᴘ value of an (endothermic forward) reaction when the temperature increases

Answer 13

A new Kᴄ or Kᴘ value is made (Larger than before), an the system is therefore no longer in equilibrium. The product’s partial pressure or concentration must increase and the reactants concentration or pressure must decrease until the new Kᴄ or Kᴘ values are met. The system will then be in the new equilibrium.

Question 14

If the forward reaction is endothermic and the temperature increases what happens the the equilibrium constant?

Answer 14

The equilibrium constants increase.

Question 15

What affects equilibrium positions and what affects equilibrium constants?

Answer 15

Positions:
- Concentration
- Pressure
- Temperature.

Constants:
- Temperature

Question 16

N₂O₄ ⇌ 2NO₂
What occurs when the concentration of N₂O₄ is increased?

Answer 16

The system is no longer in equilibrium, and the Kᴄ value will of decreased, (which cannot occur), the concentration of N₂O₄ must decrease, and 2NO₂ conc must increase, to return the system to the origional Kᴄ value, a new equilibrium position is made shifted to the right.

Question 17

N₂O₄ ⇌ 2NO₂
What occurs when the pressure is increased?

Answer 17

If the pressure is increased the Kᴘ value will increase, (which cannot occur), the partial pressure of 2NO₂ must decrease and increase for N₂O₄. This returns the system to the origional Kᴘ value, a new position of equilibrium is made shifted to the left.