Factors affecting equilibrium
I can explain how changes in pressure, temperature and concentration, as well as addition of catalysts, affect the equilibrium position of a reversible reaction.
Factors affecting equilibrium
I can explain how changes in pressure, temperature and concentration, as well as addition of catalysts, affect the equilibrium position of a reversible reaction.
Lesson details
Key learning points
- Catalysts, pressure, temperature & concentration of solutions can affect equilibrium position of a reversible reaction.
- If the conditions of a reversible reaction are changed, the equilibrium will move to counteract that change.
- A catalyst increases the rate at which equilibrium is achieved.
- Increasing temperature increases the rate of both reactions; equilibrium shifts in favour of the endothermic reaction.
- Increasing the concentration or pressure of a substance increases the rate of reaction; equilibrium shifts in response.
Common misconception
At dynamic equilibrium the reactions stop; increasing pressure always shifts equilibrium to one side; increasing temperature always favours product formation; catalysts shift the equilibrium position.
At dynamic equilibrium, reactions continue at equal rates. Pressure shifts equilibrium only if gas molecule numbers differ. Temperature favours the endothermic direction when increased. Catalysts speed up reaching equilibrium but don't shift it.
Keywords
Le Chatelier’s principle - states that if a dynamic equilibrium is disturbed by changing the conditions, the equilibrium position ‘shifts’ to counteract the change.
Dynamic equilibrium - occurs in a closed system when the forward and backward reactions of a reversible chemical reaction occur at the same rate; and the concentrations of reactants and products remain constant.
Equilibrium position - refers to the relative concentrations of reactants and products in a reversible reaction at equilibrium.
Reaction rate - is the speed with which a chemical reaction takes place, measured by the amount of a reactant used or amount of product formed in a given time.
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Video
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Starter quiz
6 Questions
a state where the forward and backward reaction rates are equal
the speed of chemical reactions: amount of matter used/made over time
factors including temperature and pressure that affect reaction rate
the amount of reactant or product in a defined volume of space
Exit quiz
6 Questions
a chemical which speeds up the rate at which equilibrium is achieved
the relative concentrations of reactants and products at equilibrium
the equilibrium position shifts to counteract a change in conditions