TOPIC 10 - EQUILIBRIUM I Flashcards
(9 cards)
What is a dynamic equilibrium?
The forward and reverse rate of reaction is the same and remains at a constant rate. At this point, the concentrations of the reactants and products are constant and appear not to change.
Le Chatelier’s principle
When a system is subject to change, the system will alter to lessen the effect of that change.
How can you use Le Chatelier’s principle to predict the effects of changes in temperature?
Increasing temperature favours the endothermic direction as excess heat needs to be removed from the system to lessen the effect of the initial increase. It will increase the yield of the endothermic products.
Decreasing the temperature favours the exothermic reaction as heat needs to be gained and the yield of the exothermic products will be increased.
How can you use Le Chatelier’s principle to predict the effects of changes in concentration?
Increasing the concentration of the reactants will favour the reaction that produces the products as more molecules are available to react. It will increase the yield of the products.
Decreasing the concentration of products will favour the reaction that reforms the reactants.
How can you use Le Chatelier’s principle to predict the effects of changes in pressure?
Increasing pressure favours the side of the reaction with fewer moles as this will help to release the build up in pressure. It will increase the yield of the products on this side of the reaction.
Decreasing pressure favours the side of the reaction with more moles as pressure has been lost. The yield of the products on this side of the reaction will be increased.
What does a catalyst do to the equilibrium?
Catalysts appear not to affect the equilibrium position as they affect the forward and backward reaction equally. However, it does allow equilibrium to be reached faster.
Why is the value of Kc not affected by changes in concentration?
If the concentration of the reactant increases, equilibrium will shift to the right to use some of the extra which increases the concentration of the products. Increase in both the products and reactants means Kc stays the same.
Why is a compromised temperature used for a reversible reaction in an industrial process?
Reactions are more successful at high temperatures as the particles are moving faster so they will be more collisions. These collisions also have more energy.
Low temperature lead to slow rate of reactions which is not economically viable.
Why is a compromised pressure used for a reversible reaction in an industrial process?
Gas reactions are more successful at high pressure as there the same number of particles in a smaller space so there will be more collisions.
High pressure is expensive to build and maintain and the higher yield is not worth the cost.
High pressures could lead to leaks and explosions.
