Topic 7: Equilibrium

Equilibrium

  • When both forward and reverse reactions occurring simultaneously have the same rate of reaction. There is no change in the amount of products or reactants​

Equilibrium constant (Kc)

Change in conditions affecting equilibrium constant and position

  • Increase in concentration of reactants

    • Position:​ favours the RHS

    • Equilibrium constant: No change

  • Increase in concentration of products

    • Position:​ favours the LHS

    • Equilibrium constant: No change

  • Increase in pressure

    • Position:​  favours the side with least volume

    • Equilibrium constant: No change

  • Decrease in pressure

    • Position:​ favours the side with most volume

    • Equilibrium constant: No change

  • Increase in temperature

    • Position:​ favours the endothermic reaction

    • Equilibrium constant: May change

  • Decrease in temperature

    • Position:​ favours the exothermic reaction

    • Equilibrium constant: May change

  • Addition of catalyst

    • Position:​ No change, the system will reach equilibrium faster; as both reates increase equally

    • Equilibrium constant: No change

Reaction quotient (Q)

Definition: ratio of concentration of products to reactants

Q=Kc

  • The system is at equilibrium

Q>Kc

  • Concentration of products is greater than reactants

  • Reverse reaction is favoured until equilibrium

Q<Kc

  • Concentration of reactants is greater than products

  • Forward reaction is favoured until equilibrium

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