Science - Ch. 10 Lesson 3

Question 1

What is a physical change?

Answer 1

A physical change is a change in size, shape, form, or state of matter in which the matter’s identity stays the same.

Question 2

Does matter become different during a physical change?

Answer 2

During a physical change, the matter does not become something different even though physical properties change.

Question 3

What is physical change’s word origin?

Answer 3

physical from Greek physika, means “natural things” change from Latin cambire, means “to exchange”

Question 4

How does a solid reach its melting point?

Answer 4

When thermal energy is added to a solid, the particles in the solid move faster and faster, and the temperature increases. When the particles are moving too fast for attractive forces to hold them tightly together, the solid reaches its melting point.

Question 5

How does a liquid reach its boiling point?

Answer 5

When the particles in a liquid are moving so fast that attractive forces cannot hold them close together, the liquid reaches its boiling point.

Question 6

What happens in sublimation?

Answer 6

Sublimation occurs when a solid changes directly to a gas without first becoming a liquid

Question 7

What happens when you remove thermal energy from a gas?

Answer 7

When thermal energy is removed from a gas, particles in the gas move more slowly and the temperature decreases. Condensation occurs when the particles are moving slowly enough for attractive forces to pull the particles close together.

Question 8

What happens when you remove thermal energy from a liquid?

Answer 8

After the gas has completely changed to a liquid, removing more thermal energy from the liquid causes particles move even more slowly. Freezing occurs when the particles are moving so slowly that attractive forces between the particles hold them tightly together.

Question 9

What is deposition?

Answer 9

Deposition is the change from a gas directly to a solid.

Question 10

Why is dissolving a physical change?

Answer 10

Dissolving, or evenly mixing, is a physical change because the identities of the substances involved do not change.

Question 11

What is conservation of mass?

Answer 11

Conservation of mass refers to the fact that the total mass before and after a physical change is the same.