5.1.8: Equilibrium constants and their significance Flashcards
What does the magnitude of the equilibrium constants, Kc and Kp , indicate?
The extent of a chemical reaction.
What would an equilibrium constant, K, with a value of 1 indicate?
That the position of equilibrium half way between the reactants and products.
When K»_space; 1
- The reaction is product favoured
- The products on the right-hand side predominate at equilibrium.
When K «_space;1
- The reaction is reactant favoured
- The reactants on the left-hand side predominate at equilibrium.
How does an increase in temperature affect the equilibrium?
-Shifts the position of equilibrium in the endothermic direction.
How does a decrease in temperature affect the equilibrium?
-Shifts the position of equilibrium in the exothermic direction.
What are shifts in the position of equilibrium controlled by?
-The rate constant, which changes its value only with changes in temperature
If the forward reaction is endothermic…
- K increases as temperature increases.
- The eqm. yield of products, on the right-hand side increases.
- The eqm. yield of reactants, on the left-hand side decreases.
If the forward reaction is exothermic…
- K decreases as temperature increases.
- The eqm. yield of products, on the right-hand side decreases.
- The eqm. yield of reactants, on the left-hand side increases.
What is the equilibrium constant, K, unaffected by?
Changes in concentration and pressure.
How does the presence of a catalyst affect K?
- It doesn’t.
- catalysts affect the rate of a chemical reaction but not the position of equilibrium.
Why does a catalyst not affect K?
- Catalysts speed up both the forward and reverse reactions in the equilibrium by the same factor.
- Equilibrium is reached more quickly, but the equilibrium position, and hence the value of the equilibrium constant, is unchanged by the action of a catalyst.
