Equilibria Flashcards
(14 cards)
What is le Chatelier’s principle?
When a system in equilibrium is subjected to an external change the system readjusts itself to minimise the effect of that change.
If there are more products formed, the position of the equilibrium has shifted to…
the right
If there are more reactants formed, the position of the equilibrium has shifted to…
the left
What is dynamic equilibrium?
When the rate of the forward reaction is equal to the rate of the reverse reaction.
When the concentrations of reactants and products do not change
What is the meaning of a closed system?
isolated from surroundings
temperature, pressure, concentration of reactants and products are unaffected by outside influences
An increase in temperature shifts the equilibrium position…
in the endothermic direction (enthalpy change is positive)
A decrease in temperature shifts the equilibrium position…
in the exothermic direction (enthalpy change is negative)
What is the effect of pressure changes on equilibrium?
The position of equilibrium will change if there are more gaseous molecules on one side of the equation than the other.
Increasing the pressure of the system will shift the position of equilibrium…
to the side with fewer molecules, reducing the pressure of the system.
What does the value of Kc tell us?
The larger the value of Kc, the further the position of equilibrium lies to the right hand side and the greater the concentrations of the products compared to the reactants.
What is homogenous equilibria?
A homogenous equilibrium contains equilibrium species that all have the same state or phase.
What is heterogenous equilibria?
A heterogenous equilibrium contains equilibrium species that have different states or phases.
If the forward reaction is exothermic…
the equilibrium constant decreases with increasing temperature
so the equilibrium yield is increased
If the forward reaction is endothermic…
the equilibrium constant increases with increasing temperature
which increases yield of the products
