In real chemical system, what factor would control the relative concentrations of reactants and products......

Question

In real chemical system, what factor would control the relative concentrations of reactants and products present at equilibrium?

Answer 1

In real chemical systems, equilibrium is no always reached. It can only be reached in systems where both the forward and backward reactions are possible.

For example, ammonia gas reacted with water:

NH3 (g) + H2O (l) <==> NH4+ (aq) + OH- (aq)

The factor that would control the relative concentrations of reactants and products present at equilibrium is called the equilibrium constant.

An example of a chemical reaction which would not reach equilibrium is the burning or Butane (like from a cigarette lighter) in air:

2 CH3CH2CH2CH3 (g) + 13 O2 (g) --> 8 CO2 (g) + 10 H2O (g)

This reaction does not go backward.