Equilibrium Constant, Rxn Quotients, and Le Chatelier's Principle

Large Equilibrium Constant (K)

more products than reactants

Small Equilibrium Constant (K)

more reactants than products.

Relationship Between K and Chemical Equation

1.If the equation is reversed, K is ________________

2.If the coefficients in the equation are multiplied by a factor, the equilibrium constant is ___________ by the same factor

3.If two or more chemical equations are added to obtain an overall equation, the equilibrium constants are _______________

1. inverted

2. raised

3. multiplied

Reaction Quotients

The reaction quotient, Qc, is defined in the same way as the equilibrium constant, Kc, except that the concentrations in Qc are not necessarily equilibrium values.

Q>K

more reactants must be formed (shifts left)

Q

more products (shifts to the right

Q=K

Reactants and products are at equilibrium

Le Châtelier's Principle

when a chemical system at equilibrium is disturbed, the system shifts in a direction that minimizes or relieves the disturbance.

the concentration disturbance of an added reactant or product is relieved by net reaction in the direction that ___________ the added substance.

consume

the concentration disturbance of a removed reactant or product is relieved by net reaction in the direction that ____________ the removed substance

replinishes

an increase in pressure by reducing the volume will bring about net reaction in the direction that ___________ the number of moles of gas

decreases

a decrease in pressure by enlarging the volume will bring about net reaction in the direction that ___________ the number of moles of gas.

increases

Adding inert gas has ____ __________ on equilibrium

no effect

If reaction has equal number of moles of gas on both sides of equation, change in volume has ____ __________ on equilibrium

no effect

Exothermic Reaction- increase temp

shifts left

Exothermic Reaction- decrease temp

shift right

Endothermic reaction-increase temp

shifts right

Endothermic reaction-decrease temp

shifts left