Lesson 2.

Question 1

List the key differences between physical and chemical changes.

Answer 1

Physical changes are reversible- chemical changes typically are not. Chemical changes produce a new substance- physical changes don’t.

Question 2

Name three examples of chemical changes.

Answer 2

Chemosynthesis/Combustion/Oxidation.

Question 3

Name three examples of physical changes.

Answer 3

Melting/Freezing/Dissolving.

Question 4

What is wrong about using the word chemical as a noun?

Answer 4

When referring to chemicals, people typically mean disinfectants and artificial fertilisers. However, all substances are chemicals, so using the term “chemicals” as a noun is not helpful.

Question 5

TRUE OR FALSE:
All substances contain chemicals.

Answer 5

True.

Question 6

What happens to particles during a physical change?

Answer 6

When a substance changes state, its particles stay the same but their arrangement and movement change.

Question 7

What happens to particles during a chemical change?

Answer 7

In a chemical change, particles break up and then join together in different ways. This is why new substances are made.