7.2 Equilibrium Law and the Equilibrium Constant

equilibrium constant. represents? and sig?

represents: extent of reaction

sig: whether prod or react is favoured at equilib--It is used to predict the amounts of reactants and products at equilibrium, given the amounts of starting materials.

what is the unit of Keq? and how does it relate to temperature?

The constant is dimensionless and its value changes with the temperature of the system

limitations on Equilibrium Constant

The value of the equilibrium constant, K, depends on temperature. A stated value for an equilibrium constant must specify temperature.

Heterogeneous Equilibria

Some systems have them in different phases

homogeneous equilibria

where the reactants and products are all in the same phase

why dont we include solid and liq in Keq?

concentrations of entities in the solid or liquid state are not included in the equilibrium law expression, because their concentrations do not change - they are CONSTANT.

Magnitude of Keq determines

the balance of a reaction and whether the amount that has reacted can be treated as negligible when compared to other concentrations

Keq is very large

the equilibrium lies very much to the right; products are favoured: more prod

If Keq is very small (K<<1)

the equilibrium lies very much to the left; reactants are favoured: more react

•When Keq is neither very large nor very small (K ≅ 1)

neither reactants, nor products are favoured at equilibrium: equal amt of react and prod

K'

represents the equilibrium constant for the reverse process-->the equilibrium constant for the forward and reverse reactions are reciprocal values.