Chapter 19 - Equilibrium Flashcards
What are the two main types of equilibria?
Homogenous and heterogenous equilibria.
What is a homogenous equilibrium?
A homogenous equilibrium contains equilibrium species that all have the same state or phase. for example, all species in a chemical equation are gases.
What is a heterogeneous equilibrium?
A heterogenous equilibrium contains species that have different states of phases. Additionally, in heterogeneous equilibria the concentration of solids and liquids are essentially constant so any species that are solids and liquids are omitted from the Kc expression.
What species does Kc only include?
Kc only includes species that are (g) or (aq).
What does the value of equilibrium constant K refer to?
The value of K gives the exact position of equilibrium.
What condition allows the value of K to change?
The value of K will only change when there are changes to the temperature, any modifications to concentration, pressure, or the presence of a catalyst will not cause K to change its value. Only temperature allows the value of K to change.
What happens to the equilibrium constant if the forward reaction is exothermic?
a. The equilibrium constant decreases with increasing temperature.
b. raising the temperature decreases the equilibrium yield of products.
What happens to the equilibrium constant if the forward reaction is endothermic?
a. The equilibrium constant increases with increasing temperature.
b. Raising the temperature increases the equilibrium yield of products.
State le Chatelier’s principle.
The position of equilibrium will shift so as to minimise the effect of any change in conditions.
What factors should you include when considering a high pressure?
a. A higher pressure may be too expensive.
b. A higher pressure may cause safety problems.
What factors should you include when considering a high temperature?
A high temperature will increase the rate of reaction without shifting the equilibrium or compromising the equilibrium yield.
