Reversible reactions Flashcards
What is a reversible reaction?
One where the products of the reaction can themselves react to produce the original reactants (the reaction can go both ways).
What does the symbol for a reversible reaction look like?
Two arrows in reverse directions (⇌)
What will reversible reactions reach?
Equilibrium.
What happens when a reversible reaction takes place in a closed system?
A state of equilibrium will always be reached.
What does equilibrium mean?
That the amounts of reactants and products will reach a certain balance and stay there.
What does a closed system mean?
That none of the reactants or products can escape.
What is the overall effect of a reversible reaction?
Nil.
Why is the overall effect of a reversible reaction nil?
Because the forwards and reverse reactions cancel each other out.
At what rate are the reactions taking place in both directions?
Exactly the same rate.
In a reversible reaction what can be changed?
The position of equilibrium.
What does the position of equilibrium depend upon in a reversible reaction?
-Temperature.
-Pressure.
That is surrounding the reaction.
What do we deliberately alter tr temperature and pressure in a reversible reaction to do?
Move the position of equilibrium to give more product and less reactants.
What are all reversible reactions regarding temperature?
Exothermic in one direction and endothermic in the other.
What happens if you raise the temperature in a reversible reaction?
The endothermic reaction will increase to use up the extra heat.
What happens if you reduce the temperature in a reversible reaction?
The exothermic reaction will increase to give out more heat.
What do many reversible reactions have?
A greater volume of gas molecules on one side, either of products or reactants.
What happens if you raise the pressure in a reversible reaction
It will encourage the reaction which produces less volume.
What happens if you lower the pressure in a reversible reaction?
It will encourage the reaction which produces more volume.
What does adding a catalyst to a reversible reaction not do?
It doesn’t change the equilibrium position.
Why doesn’t the catalyst change the position of equilibrium in a reversible reaction?
As catalysts speed up both the forward and backward reactions by the same amount.
What does adding a catalyst to a reversible reaction mean?
That the reaction reaches equilibrium quicker, but you end up with the same amount of product as you would without the catalyst.
What happens if in a reversible reaction, there is an equal amount of gas molecules on each side?
Changing the pressure won’t make any difference to the equilibrium position (But it still affects the rate of reaction).
