Effect of Temperature on Equilibrium and Keq

Front

What happens to the equilibrium position when heat is added to an exothermic reaction?

Back

The equilibrium shifts to the left.

Front

Why does the equilibrium shift to the left when heat is added to an exothermic reaction?

Back

The reaction tries to use up the added heat by making more reactants (H2 and Cl2), thus using up HCl and heat.

Front

What happens to the Keq value when heat is added to an exothermic reaction?

Back

The Keq value decreases.

Front

What is the Keq expression for the reaction H2(g) + Cl2(g) ⇌ 2HCl(g)?

Back

Keq = [HCl]^2 / ([H2] [Cl2])

Front

What happens to the equilibrium position when heat is added to an endothermic reaction?

Back

The equilibrium shifts to the right.

Front

Why does the equilibrium shift to the right when heat is added to an endothermic reaction?

Back

The reaction uses up the added heat by making more products (NO2) at the expense of reactants (N2O4).

Front

What happens to the Keq value when heat is added to an endothermic reaction?

Back

The Keq value increases.

Front

What is the Keq expression for the reaction N2O4(g) + heat ⇌ 2NO2(g)?

Back

Keq = [NO2]^2 / [N2O4]

Front

What are the two questions to consider when discussing the effect of heat on Keq?

Back

1) Is the reaction endothermic or exothermic? 2) Is heat added or removed?

Front

What happens to the equilibrium position and Keq value when heat is removed from an exothermic reaction?

Back

The equilibrium shifts to the right and the Keq value increases.