Equilibrium Flashcards
What is an irreversible reaction?
Reaction where reactants can change into products but the products cannot change back into the reactants.
E.g. burning a newspaper
What is a reversible reaction?
Reaction where reactants can change into products and the products can change back into the reactants.
E.g. N2 + 3H2 - 2NH3 (Ammonia)
What is an open system?
Reactions that happens in a container where one or more of the reactants or products cannot change escape e.g. saucepan of boiling water
What is a closed system?
If a reaction happens in a container where none of the reactants or products can escape e.g. saucepan of boiling water with a lid.
Reversible reactions that happens in in a closed system eventually reach an equilibrium.
What is dynamic equilibrium?
Occurs when the rate of the forward reaction is equal to the rate of reverse reaction resulting in the amount of reactants and products remaining contant
What is equilibrium?
Considered to be a closed system where only the reactants and products are present
How does the position of equilibrium differ depending on the reactants and products?
If there are more products than reactants then the position of equilibrium is to the right hand side.
If there are more reactants than products then the position of equilibrium is to the left.
What is the position of equilibrium?
In a reversible reaction is a measure of how far the reaction has proceeded to the right (towards the products) or has it remained to the left (towards the reactants)
Conditions for equilibrium to occur in a reversible reaction?
Closed system.
Only reactants and products for the given equilibrium present.
What is Le Châtelier’s Principle?
States that 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 (or system)?
One in which all the reactants and products are in the same state
How does changes in concentration affect equilibrium?
If concentration is added to the reactants then equilibrium will move to the right to use it up and reduce the concentration and more product will be produced.
If concentration is decreased in say product the equilibrium will move to the right to produce more product.
How does change in pressure affect equilibrium?
If pressure is increased equilibrium will go to the side with lower pressure (less molecules) creating more of that product of reactants.
If pressure is decreased then equilibrium will go the side with more pressure (more molecules).
Pressure only matters if there is gas present.
How does changes in temperature affect equilibrium?
If the forward reaction is exothermic and the temperature in increased then equilibrium will shift to the left producing more reactants.
If the forward reaction is endothermic and the temperature is increased then equilibrium will shift to the right to produce more product.
What conditions are used for the Haber Process?
450 degrees to get a good rate of reaction and so that the yield of ammonia is high enough.
200 atmospheres so to get a good yield of ammonia but not too much as to not be too expensive.
Catalysts used is Iron.
Why should you add a catalyst to equilibrium?
It reduces the time to reach equilibrium but does not change the position of equilibrium, this is because the catalyst increased the rates of the forward and reverse reactions by the same amount.
