Chemical equilibrium
Where on the exam paper
Chemical equilibrium typically comes up in Q7 and Q9 but may be a part of Q4 (short) and Q11
Definitions
1. Reversible Reaction – A reaction that can go both directions
2. Rate of reaction at equilibrium – rf =rr
3. Chemical Equilibrium – A state of dynamic equilibrium where the rate of the forward
reaction is equal to the rate of the reverse reaction
4. Le Chatelier’s Principle – If a stress is applied to a system in equilibrium, then the system
reacts to oppose the applied stress ( or If any of the factors affecting the rate of the forward
or reverse reactions are changed, the system will try to adjust to diminish this change)
5. Kc ( equilibrium constant ) – Is temperature dependant
Typical Exam questions
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Write equilibrium constant (Kc) expressions.
State le Chateliers principle.
Effect of Conditions on concentration of product / reactant
o Temperature
o Pressure
o Concentration of other species
o Catalyst
Equlibrium constant ( and effect on Kc)