Magnitude of the Equilibrium Constant
Chemistry: IB Diploma Higher Level, topic 5.6.2
Magnitude of the Equilibrium Constant
The equilibrium constant for a reaction tells you the relative position of the reversible reaction at equilibrium.
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Large equilibrium constants
- A reaction with a large equilibrium constant (K) will be at equilibrium when most of the reactant has been converted into the product.
- An equilibrium constant greater than one indicates that the forward reaction dominates.
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Small equilibrium constants
- A reaction with a small equilibrium constant (K) will be at equilibrium when very little of the reactant has been converted into the product.
- An equilibrium constant less than one indicates that the backward reaction dominates.
K does NOT affect the rate
- The size of the equilibrium constant (K) does NOT show how fast or slow equilibrium will be reached.
- Some equilibria are reached so quickly that they are almost instant.
- Some equilibria are reached so slowly that it is very hard to see any change over the course of days or years.
Test yourself on Magnitude of the Equilibrium Constant
If Kc is greater than one, what does it indicate?
When does the backward reaction dominate?