Reversible reactions

Question 1

How can equilibrium be achieved?

Answer 1

.When reactants react their concentration falls, so the forward reaction will slow down
.But as more products are made their concentration increases so the backward reaction will speed up
.After a while the forward and backward reaction will be going at the same rate - this is equilibrium

Question 2

What is a closed system?

Answer 2

Where none of the reactants or products can escape and nothing can get in

Question 3

What is a dynamic equilibrium?

Answer 3

Both reactions are happening but there’s no overall effect, the concentrations of reactants and products have reached a balance and won’t change

Question 4

What does it mean if the equilibrium lies to the right?

Answer 4

The concentration of products is greater than that of the reactants

Question 5

What does it mean if the equilibrium lies to the left?

Answer 5

The concentration of the reactants is greater than that of the products

Question 6

What does the position of equilibrium depend on?

Answer 6

.Temperature
.Pressure
.Concentration

Question 7

In reversible reactions, if it is endothermic in one direction what is it in the other?

Answer 7

Exothermic

Question 8

What is the energy transferred from the surroundings in the endothermic reaction equal to?

Answer 8

The energy transferred to the surroundings in the exothermic reaction

Question 9

What does anhydrous mean?

Answer 9

Without water

Question 10

What does hydrated mean?

Answer 10

With water

Question 11

What happens if you heat blue hydrated copper (ii) sulfate crystals?

Answer 11

It drives the water off and leaves white anhydrous copper (ii) sulfate powder, this is endothermic

Question 12

What happens if you add a couple of drops of water to the white anhydrous copper (ii) sulfate powder?

Answer 12

You get the blue hydrated copper (ii) sulfate crystals back, this is exothermic

Question 13

What is Le Chatelier’s Principle?

Answer 13

The idea that if you change the conditions of a reversible reaction at equilibrium, then the system will try to counteract the change

Question 14

What happens if you decrease the temperature?

Answer 14

The equilibrium will move in the exothermic direction to produce more heat, this means you will get more products for the exothermic reaction and fewer for the endothermic reaction

Question 15

What happens if you increase the temperature?

Answer 15

The equilibrium will move in the endothermic direction to try and decrease it, this means you will get more products for the endothermic reaction and fewer for the exothermic reaction

Question 16

What does changing the pressure only effect?

Answer 16

Gasses

Question 17

What happens if you increase the pressure?

Answer 17

The equilibrium tries to reduce it, it moves in the direction where there are fewer molecules of gas

Question 18

What happens if you decrease the pressure?

Answer 18

The equilibrium tries to increase it, it moves in the direction where there are more molecules of gas

Question 19

How can you find out which side of a reaction has more molecules of gas?

Answer 19

The balanced symbol equation

Question 20

What happens if you increase the concentration of the reactants?

Answer 20

The system will decrease it by making more products

Question 21

What happens if you decrease the concentration of products?

Answer 21

The system will increase it again by reducing the amounts of reactants