What is Le Chatelier's Principle?

The principle states that, if any system in dynamic equilibrium is subjected to a change, a process will act to minimise the change to restore equilibrium.

 

These changes could be in concentrations, pressure or temperature. The following reaction can be used to demonstrate this:

N2(g) + 3H2(g) <-> 2NH3(g)     (exothermic)

1. Concentration: An increase in the concentration of a reactant will be countered by a shift in eqiulibrium to the right - the product side. This will remove reactant and so decrease the concentration again.

2. Pressure: An increase in total pressure will cause a shift in equilibrium to the right - the side with least moles of gas. As there are less moles of gas in the product, this will reduce the pressure again.

3. Temperature: A decrease in temperature will cause a shift in equilibrium to the right - the exothermic direction. As an exothermic reaction releases heat, this will increase the temperature to counter the original change.

AM

Related Chemistry A Level answers

All answers ▸

Explain how a hydroxynitrile is produced from a ketone


Explain why atomic radius decreases across a period


You have 3.51g of hydrated zinc sulphate. You heat up the zinc sulphate until all the water has evaporated from it. The weight after heating is 1.97g. Find how many H2O molecules per zinc sulphate molecule there are in the hydrated form of it.


How do you describe the process of recrystallisation to purify a product?