C8.3 - The effect of temperature

Question 1

What happens when you increase the temperature?

Answer 1

When you increase the temperature, it increases the rate of reaction

Question 2

What can you use to reduce the temperature and slow down the rate of reaction?

Answer 2

You can use fridges and freezers to:

1. Reduce the temperature
2. Slow down the rate of reaction

Question 3

When food goes off, it is because of what?

Answer 3

When food goes off, it is because of chemical reactions

Question 4

When food goes off, it is because of chemical reactions, so what does reducing the temperature do?

Answer 4

When food goes off, it is because of chemical reactions, so reducing the temperature slows down these unwanted reactions

Question 5

What tells you why raising the temperature increases the rate of a reaction?

Answer 5

Collision theory tells you why raising the temperature increases the rate of a reaction

Question 6

Collision theory tells you why raising the temperature increases the rate of a reaction.
What are there?

Answer 6

There are 2 main reasons, particles collide:

1. More often
2. With more energy

Question 7

What happens when you heat up a substance?

Answer 7

When you heat up a substance, energy is transferred to its particles

Question 8

When you heat up a substance, energy is transferred to its particles.
What does this mean in solutions and in gases?

Answer 8

In:
1. Solutions
2. Gases
,this means that the particles move around faster

Question 9

When you heat up a substance, energy is transferred to its particles.
In solutions and in gases, this means that the particles move around faster.
What happens when particles move around faster?

Answer 9

When particles move around faster, they also collide more often

Question 10

What happens when particles react more frequently?

Answer 10

When particles react more frequently, there are more chances for them to react

Question 11

When particles react more frequently, there are more chances for them to react.
What does this do?

Answer 11

This increases the rate of reaction

Question 12

What do particles that are moving around more quickly have?

Answer 12

Particles that are moving around more quickly have more energy

Question 13

Particles that are moving around more quickly have more energy.
What does this mean?

Answer 13

This means that any collisions they have are much more energetic

Question 14

What happens when you increase the temperature of a reacting mixture?

Answer 14

When you increase the temperature of a reacting mixture, a higher proportion of the collisions will result in the reaction taking place in any given time

Question 15

When you increase the temperature of a reacting mixture, a higher proportion of the collisions will result in the reaction taking place in any given time.
Why is this?

Answer 15

When you increase the temperature of a reacting mixture, a higher proportion of the collisions will result in the reaction taking place in any given time, because a higher proportion of particles have energy greater than the activation energy

Question 16

What does an increased proportion of particles exceeding the activation energy do?

Answer 16

An increased proportion of particles exceeding the activation energy has a greater effect on rate than the increased frequency of collisions

Question 17

What happens around room temperature, if you increase the temperature of a reaction by 10 degrees Celsius?

Answer 17

Around room temperature, if you increase the temperature of a reaction by 10 degrees Celsius, the rate of the reaction will roughly double

Question 18

Describe the particles in a cold reaction

Answer 18

The particles in a cold reaction:

1. Slow movement
2. Less frequent collisions
3. Little energy

Question 19

Describe the particles in a hot reaction

Answer 19

The particles in a hot reaction:

1. Fast movement
2. More frequent collisions
3. More energy

Question 20

Example results for an investigation on the effect of temperature on the rate of a reaction.
What does the negative slope show?

Answer 20

The negative slope shows that as the temperature increases, the time it takes for the reaction to finish decreases

Question 21

Example results for an investigation on the effect of temperature on the rate of a reaction.
The negative slope shows that as the temperature increases, the time it takes for the reaction to finish decreases.
However, what happens as the temperature increases?

Answer 21

As the temperature increases, the:
1. Rate of the reaction
Or,
2. 'Mean rate of reaction'
also increases