5. Equilibria

Question 1

What is an equilibrium?

Why do some reactions not reach equilibrium?

Answer 1

Constant ratio of product and reactant concentration, no change in amounts

Very slow
Concentration of either products or reactants may be very low
Reactions in living organisms do not reach equilibrium as there is a continuous flow of metabolism

Question 2

What is the equation for Keq (equilibrium constant)?

What is it used to estimate?

Answer 2

Keq: [P]^p x [Q]^q/ [A]^a x [B]^b
Moles of the product is to the power of.. i.e. if there is 2H+ = [H+]^2
Products/ Reactants

Estimate: How much product and reactant will be present at equilibrium given initial concentrations of reactants

Question 3

When reactions reach equilibrium, there is no change in concentrations of reactants and products (rate of reaction is 0), is there still a chemical reaction taking place?

Answer 3

YES!
Rate of converting reactants to products is now same as rate of reaction converting products to reactants= No overall rate of reaction
MEANS: Rate of forward reaction= Rate of back reaction