C6 - Energy Changes

Question 1

What is an exothermic reaction?

Answer 1

(thermal) energy is released from the reaction.

Question 2

What happens to the temperature of a reaction mixture after an exothermic reaction?

Answer 2

The temperature of the reaction mixture goes up (it feels hot).

Question 3

What is an endothermic reactions?

Answer 3

(thermal) energy is taken into the reaction.

Question 4

What happens to the temperature of a reaction mixture after an endothermic reaction?

Answer 4

The temperature of the reaction mixture decreases (it feels cold).

Question 5

What are the SI for energy?

Answer 5

Joules (J)

Question 6

What is activation energy?

Answer 6

The minimum amount of energy required to start a reaction.

Question 7

What is bond breaking?

Answer 7

Bonds in the reactants are broken during the reaction.

Question 8

What is bond making?

Answer 8

Bonds in the products are made during the reaction.

Question 9

What direction do arrows point in an endothermic reaction?

Answer 9

Up

Question 10

What direction do arrows point in an exothermic reaction?

Answer 10

Down

Question 11

Where is the overall energy change measured from?

Answer 11

The reactants to the products.

Question 12

What is on the y-axis of an exo/endothermic reaction?

Answer 12

Energy.

Question 13

What is on the x-axis of an exo/endothermic reaction?

Answer 13

The progress of reaction.

Question 14

What is the formula for energy change?

Answer 14

products - reactants

Question 15

Name two exothermic reactions.

Answer 15

Neutralisation and Displacement.

Question 16

What type of reaction is Salt Dissolving and Precipitation?

Answer 16

Could be endo or exo depending on the salt and other factors.

Question 17

What is the difference between a chemical reaction and a physical process?

Answer 17

In a chemical reaction a new chemical is made and in a physical process no new chemical is formed.

Question 18

What does OIL RIG stand for?

Answer 18

Oxidation
Is
Loss
Reduction
Is
Gain

Question 19

What must happen for a reaction to happen?

Answer 19

A successful collision.

Question 20

What is the rate of reaction?

Answer 20

The number of successful collisions per second.

Question 21

What are five factors that affect the rate of reaction?

Answer 21

Temperature
Concentration
Surface Area aka particle size
Pressure
Catalyst

Question 22

How does concentration affect the rate of reaction?

Answer 22

Higher concentration = higher frequency, energy stays the same = higher rate of reaction

Question 23

How does pressure affect the rate of reaction?

Answer 23

Increased pressure = higher frequency, energy stays the same = higher rate of reaction

Question 24

How does surface area affect the rate of reaction?

Answer 24

Increased surface area = higher frequency, energy stays the same = higher rate of reaction

Question 25

How does temperature affect the rate of reaction?

Answer 25

Increased temperature = higher frequency, higher energy = higher rate of reaction

Question 26

How does a catalyst affect the rate of reaction? [4]

Answer 26

With a catalyst:
- activation energy is lower
- frequency is increased
- energy stays the same
- higher rate of reaction

Question 27

What is a neutralisation reaction?

Answer 27

Acis + Base