1. Effect of volume change on equilibria
If you decrease the volume, you increase concentration, this will have a varying effect on the equilibria depending upon which side of the reaction has fewer molecules

2. Example: N2(g) + 3H2(g) === 2NH3 (g)
Set equilibrium concentrations to:
[N2] = M
[H2] = M
[NH3] = 1.75 M in a volume of 1.0 liters
What is the value of Kc? How will the equilibrium shift if the volume is decreased to liters?

3. Summary: Effect of Volume on Equilibrium
For reaction with volume decrease, the equilibrium shifts toward the side of the reaction with fewer molecules.
For reaction with volume increase, equilibrium shifts toward side with more molecules
Applies to reactions involving gases only!

4. Effect of temperature change on equilibria
Effect will be different depending upon whether the reaction is endo- or exothermic (Refresh definitions)
Example:
C8H /2O2 === 8 CO2 + 9H2O DH = x 103

5. Another temperature example
CaCO3 === CaO + CO2 DH = kJ/mol