Chemical equilibrium

For N2 + 3H2 giving 2NH3, the equilibrium constant Kc is:

• 1 [NH3]2 / ([N2][H2]3)
• 2 [NH3]2 x [N2][H2]3
• 3 [NH3] / ([N2][H2])
• 4 [N2][H2]3 / [NH3]2

Le Chatelier's principle says a system at equilibrium responds to a disturbance by:

• 1 Increasing the change
• 2 Opposing the change
• 3 Stopping
• 4 Doubling Kc

Adding a catalyst to a reaction at equilibrium:

• 1 Does not change the value of Kc
• 2 Changes the value of Kc
• 3 Doubles the yield
• 4 Stops the reaction

If Kc is much greater than 1, the equilibrium favours:

• 1 Products
• 2 Reactants
• 3 Neither
• 4 Catalysts

Raising the temperature of an exothermic reaction at equilibrium shifts it to the:

• 1 Reactants
• 2 No shift
• 3 Catalyst
• 4 Products

A large value of Kc shows that at equilibrium there are:

• 1 More products than reactants
• 2 More reactants than products
• 3 Equal amounts
• 4 No reaction

Changing pressure has no effect on the equilibrium of a reaction when:

• 1 The number of gas moles is equal on both sides
• 2 The reaction is endothermic
• 3 A catalyst is added
• 4 The temperature is low

In the equilibrium constant expression, pure solids and liquids are:

• 1 Left out
• 2 Squared
• 3 Always 10
• 4 Included as their mass