Changes of State

Question 1

Explain the difference between physical changes and chemical changes.

Answer 1

• Physical changes do not result in the formation of a new substance / chemical changes result in formation of a new substance
• Physical changes are easily reversed / chemical changes are not easily reversed

Question 2

Name the change in which a solid becomes a liquid.

Answer 2

Melting

Question 3

Name the change in which a liquid becomes a gas.

Answer 3

Evaporation

Question 4

Name the change in which a gas becomes a liquid.

Answer 4

Condensation

Question 5

Name the change in which a liquid becomes a solid.

Answer 5

Freezing

Question 6

Explain the changes in arrangement, movement and energy of particles when a solid melts into a liquid.

Answer 6

• As solid is heated, particles gain more energy
• This makes them vibrate more about their fixed positions, weakening the forces that hold them together
• (At high enough temp, particles have enough energy to break free from their positions)

Question 7

Explain the changes in arrangement, movement and energy of particles when a liquid evaporates into a gas.

Answer 7

• As liquid is heated, particles gain even more energy
• This energy makes them move faster, which weakens the bonds holding them together
• (At high enough temp, particles have enough energy to break their bonds)

Question 8

Answer 8