Reversible reactions

Question 1

What is a reversible reaction?

Answer 1

One where the products of the reaction can themselves react to produce the original reactants (the reaction can go both ways).

Question 2

What does the symbol for a reversible reaction look like?

Answer 2

Two arrows in reverse directions (⇌)

Question 3

What will reversible reactions reach?

Answer 3

Equilibrium.

Question 4

What happens when a reversible reaction takes place in a closed system?

Answer 4

A state of equilibrium will always be reached.

Question 5

What does equilibrium mean?

Answer 5

That the amounts of reactants and products will reach a certain balance and stay there.

Question 6

What does a closed system mean?

Answer 6

That none of the reactants or products can escape.

Question 7

What is the overall effect of a reversible reaction?

Answer 7

Nil.

Question 8

Why is the overall effect of a reversible reaction nil?

Answer 8

Because the forwards and reverse reactions cancel each other out.

Question 9

At what rate are the reactions taking place in both directions?

Answer 9

Exactly the same rate.

Question 10

In a reversible reaction what can be changed?

Answer 10

The position of equilibrium.

Question 11

What does the position of equilibrium depend upon in a reversible reaction?

Answer 11

-Temperature.
-Pressure.
That is surrounding the reaction.

Question 12

What do we deliberately alter tr temperature and pressure in a reversible reaction to do?

Answer 12

Move the position of equilibrium to give more product and less reactants.

Question 13

What are all reversible reactions regarding temperature?

Answer 13

Exothermic in one direction and endothermic in the other.

Question 14

What happens if you raise the temperature in a reversible reaction?

Answer 14

The endothermic reaction will increase to use up the extra heat.

Question 15

What happens if you reduce the temperature in a reversible reaction?

Answer 15

The exothermic reaction will increase to give out more heat.

Question 16

What do many reversible reactions have?

Answer 16

A greater volume of gas molecules on one side, either of products or reactants.

Question 17

What happens if you raise the pressure in a reversible reaction

Answer 17

It will encourage the reaction which produces less volume.

Question 18

What happens if you lower the pressure in a reversible reaction?

Answer 18

It will encourage the reaction which produces more volume.

Question 19

What does adding a catalyst to a reversible reaction not do?

Answer 19

It doesn’t change the equilibrium position.

Question 20

Why doesn’t the catalyst change the position of equilibrium in a reversible reaction?

Answer 20

As catalysts speed up both the forward and backward reactions by the same amount.

Question 21

What does adding a catalyst to a reversible reaction mean?

Answer 21

That the reaction reaches equilibrium quicker, but you end up with the same amount of product as you would without the catalyst.

Question 22

What happens if in a reversible reaction, there is an equal amount of gas molecules on each side?

Answer 22

Changing the pressure won’t make any difference to the equilibrium position (But it still affects the rate of reaction).