Question

For the following endothermic reaction at equilibrium: Fe2O3 (s) + 3 H2 (g) 2 Fe(s) + 3 H2O(g) Decide if each of the following changes will increase the value of K (T = temperature). Increase the T Remove H2 (constant T) Decrease the T Decrease the volume (constant T) Add Ne(g) (constant T) Add H2 (constant T) Add a catalyst (constant T)

Answer 1

Answer:

1. K increases

2. K doesn't change

3. K decreases

4. K doesn't change

5. K doesn't change

6. K increases

7. K doesn't change

Explanation:

The equilibrium constant for a reaction is always the same value at a given temperature. So, any change in temperature will change K value.

Le chatelier principle states that if a change is imposed on a system at equilibrium, the position of the equilibrium will shift in a direction that tends to reduce that change, then we have:

1. Increase T: Since it is an endothermic reaction when temperature is raised the position of the chemical equilibrium will lie to the right because the shift will be in the direction that consumes energy. And K will increase
2. Remove H2 (T constant) will cause the system to shift to the left and H2 increases in that way. K doesn't change
3. Decrease T: It will decrease K and shift the equilibrium to the left.
4. Decrease the volume (constant T): when the volume is reduced, the system responds by reducing its volume. However, reactants and products have the same number of moles so decreasing volume doesn't affect the equilibrium position nor K value.
5. Add Ne(g): the addition of an inert gas like neon increases the total pressure but does not affect the concentrations of the reactants or products because it doesn't participate in the reaction. K will not change.
6. Add H2 will shift the equilibrium to the right to decrease H2 concentration. K will increase
7. Add a catalyst will increase the rate of reaction but it doesn't affect K value.