1.4 Equilibrium Flashcards
Define dynamic equilibrium
a reaction in which the rate of the forward reaction is equal to the rate of the backward reaction
What are the conditions for achieving dynamic equilibrium?
must take place in a closed system
Give the equation for the Haber process and state its conditions
N2(g) + 3H2(g) ⇌ 2NH3(g)
450ºC and 250atm
Give the equilibrium equation for the Haber process
Kc = [NH3]^2 / [N2][H2]^3
What is Kc?
The equilibrium constant
How are units calculated for the equilibrium constant?
based on the reaction’s equilibrium equation - all concentrations are mol/dm^3, but the units for Kc will vary as each reaction will have different amounts of products/reactants and different powers raised (derived from balanced stoichiometric equation)
What is the significance of the numerical size of the equilibrium constant?
The position of equilibrium - if the equilibrium constant is much greater than 1, products predominate over reactants (due to the nature of the equilibrium equation)
What factor affects the size of the Kc value?
temperature
What happens to Kc if the temperature increases in an endothermic reaction?
Kc increases - equilibrium position shifts towards products
What happens to Kc if the temperature decreases in an endothermic reaction?
Kc decreases - equilibrium position shifts towards reactants
What happens to Kc if the temperature increases in an exothermic reaction?
Kc decreases - equilibrium position shifts towards reactants
What happens to Kc if the temperature decreases in an exothermic reaction?
Kc increases - equilibrium position shifts towards products
