Equilibrium Flashcards
What is a reversible reaction?
A reaction where reactants can change into products and the products can change back into the reactants.
In an equation, this is represented with two arrows pointing in opposite directions at the equals point.
What is an irreversible reaction?
A reaction where reactants can change into products but the products cannot change back into the reactants.
The reaction is said to have ‘gone to completion’ and in an equation is represented by an arrow ->
If the forward reaction is exothermic what will the reverse reaction be?
Exothermic, and vice versa.
How does the energy change in a reversible reaction?
Energy stays the same.
E.g. If a reaction gives out -92 kJ of energy (exothermic) in the forward reaction, the reverse reaction will take in +92 kJ of energy (endothermic).
What an open system?
When a reaction occurs in a container where one or more of the reactants or products can escape. E.g. saucepan of boiling water.
What is a closed system?
A reaction that takes place in a container where none of the reactants or products can escape.
What is dynamic equilibrium?
Occurs when the rate of the forward reaction is equal to the rate of the reverse reaction resulting in the amount of reactants and products remaining constant.
What is an equilibrium reaction?
Considered to be a closed system where only the reactants and products are present.
Where is the position of equilibrium when there are more reactants than products?
To the left.
Where is the position of equilibrium when there are more products than reactants?
To the right.
Where is the position of equilibrium when there is a similar amount reactants and products?
In the middle.
What is Le Châtliers principal?
If a change is made to the conditions of a system at equilibrium, then the position of the equilibrium moves to oppose that change in conditions.
What is a homogeneous reaction?
One in which all reactants and products are in the same state.
How do changes in concentration affect an equilibrium reaction?
If the concentration of reactants is increased, the equilibrium will move to the right and more products are produced in order to use up the extra reactants.
If the concentration of products is increased, the equilibrium will move to the lift and more reactants are produced in order to use up the extra products.
This is in order to maintain equilibrium.
How do changes in pressure affect an equilibrium reaction?
Only applies to reactions with at least 1 gas.
If pressure is increased, the position of equilibrium will shift to the side of the reaction with the smaller number of moles, creating more of the compounds on that side. This decreases the pressure to minimise the change.
If pressure is decreased , the position of equilibrium will shift to the side of the reaction with the larger number of moles, creating more of the compounds on that side. This increases the pressure to minimise the change.
