Chemical equilibrium (Le Chatelier)

A/L Chemistry · G.C.E. Advanced Level · Grades 12–13

Aim

To observe how changes affect equilibria, following Le Chatelier’s principle.

Apparatus

• Cobalt(II) chloride solution
• Fe³⁺ and SCN⁻ solutions
• Conc. HCl, AgNO₃, hot and ice water

Method

1. Choose a system and note its starting colour.
2. Change the temperature or a concentration.
3. Observe the colour change.
4. Decide which way the equilibrium shifts.

Conclusion

When a system at equilibrium is changed it shifts to oppose the change (Le Chatelier). Heating favours the endothermic direction.