Rates & Equilibrium

Question 1

What are the two equations for mean rate of reaction?

Answer 1

Mean rate of reaction = quantity of reactant used / time taken

Mean rate of reaction = quantity of products formed / time taken

Question 2

What factors affect the rate of reaction?

Answer 2

Catalyst, temperature, surface area, pressure, concentration

Question 3

When do reactions take place?

Answer 3

When the particles collide with enough energy

Question 4

What is the activation energy?

Answer 4

Minimum amount of energy required for a reaction to occur

Question 5

What increases the likelihood of reactions happening?

Answer 5

Increasing the frequency of particles colliding and increasing the amount of energy they have

Question 6

How does increasing the temperature affect the rate of reaction?

Answer 6

Gives particles more energy leading to more frequent collisions between particles. This increases the chances of successful collisions and the rate of reaction increases.

Question 7

How do catalysts increase rate of reactions

Answer 7

By providing an alternative pathway to the products you with a lower activation energy than the reaction without the catalyst present

Question 8

What are reversible reactions?

Answer 8

A reaction where the products can react to make the reactants

Question 9

How do you investigate energy changes in reversible reactions?

Answer 9

1. Put some blue copper sulphate crystals in a test tube
2. Gently heat the crystals using a bunsen burner
3. Record observations
4. When the crystals are completely white, remove from heat and allow to cool
5. Add two or three drops of water
6. Carefully feel the base of the test tube
7. Record observations

Question 10

How do you investigate reversible reactions?

Answer 10

1. Pour our a small amount of alkali into a beaker
2. Dip your litmus paper with into the alkali
3. Note down any colour change
4. Pour out a small amount of acid into another beaker
5. Dip the same piece of litmus paper into the acid
6. Note down any colour change

Question 11

What were the results / colour changes in the reversible reaction investigation?

Answer 11

Alkali - Blue, dark blue, light blue

Acid - Purple, pink

Question 12

What is Le Chatelier’s principle?

Answer 12

If a dynamic equilibrium is disturbed by changing conditions, the position of equilibrium moves to counteract change

Question 13

What can change equilibrium?

Answer 13

Concentration, pressure, temperature

Question 14

What is equilibrium?

Answer 14

Where the forward and backwards reactions happen at the same rate