Le Châtelier's Principle and Equilibrium Shifts
Concentration: System counteracts concentration changes.
Increase reactants = shift right.
Decrease reactants = shift left.
Remove product = one-way reaction.
Pressure: Applies to gases.
Increase pressure = shift to fewer gas molecules.
Decrease pressure = shift to more gas molecules.
Inert gases (constant volume, unchanged partial pressures) = no effect.
Volume change = shift to more/fewer gas molecules.
Temperature affects equilibrium based on the enthalpy change of the reaction. For endothermic reactions (\Delta H > 0), increasing the temperature shifts the equilibrium towards the products, as
Increasing temperature
Suppose the system is in equilibrium at 300°C, and the temperature is increased 500°C. To cool down, it needs to absorb the extra heat added. In the case, the back reaction is that in which heat is absorbed. The position of equilibrium therefore moves to the left.
Decreasing temperature
Suppose the system is in equilibrium at 500°C and the temperature is reduced to 400°C. The reaction will tend to heat itself up again to return to the original temperature by favoring the exothermic reaction. The position of equilibrium will move to the right with more