Topic 7: Equilibrium
Equilibrium
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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
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Increase in concentration of reactants
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Position: favours the RHS
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Equilibrium constant: No change
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Increase in concentration of products
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Position: favours the LHS
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Equilibrium constant: No change
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Increase in pressure
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Position: favours the side with least volume
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Equilibrium constant: No change
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Decrease in pressure
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Position: favours the side with most volume
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Equilibrium constant: No change
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Increase in temperature
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Position: favours the endothermic reaction
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Equilibrium constant: May change
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Decrease in temperature
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Position: favours the exothermic reaction
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Equilibrium constant: May change
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Addition of catalyst
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Position: No change, the system will reach equilibrium faster; as both reates increase equally
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Equilibrium constant: No change
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Reaction quotient (Q)
Definition: ratio of concentration of products to reactants
Q=Kc
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The system is at equilibrium
Q>Kc
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Concentration of products is greater than reactants
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Reverse reaction is favoured until equilibrium
Q<Kc
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Concentration of reactants is greater than products
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Forward reaction is favoured until equilibrium