What is a physical change?

• A change that cannot be reversed

• A change that always involves a color change

• A change that is often reversible

• A change that produces a new substance

What is an example of a chemical change?

• Freezing water

• Melting ice

• Boiling water

• Burning wood

Which of the following is a sign of a chemical reaction?

• Change in texture

• Change in shape

• Change in size

• Formation of a gas

What happens when vinegar and baking soda are mixed?

• They become cold

• They change color

• They release carbon dioxide gas

• They form a solid

Why is dissolving salt in water considered a physical change?

• Because it changes color

• Because the salt can be recovered after evaporation

• Because the salt cannot be recovered

• Because it forms a new substance

Select all of the following that are signs or evidence of a chemical change.

• unexpected color change

• unexpected temperature change (increase or decrease in temp)

• light and/or heat is produced

• precipitate forms

• gas forms (bubbles or new smell)

Rust forming on a car is an example of a chemical change because there is an unexpected _________ change.

A phase change (like melting, freezing, evaporation, etc.) is always a __________ change.

• physical

• chemical

Baking a cake is a ___________ change.

• physical

• chemical

Ice melting is a __________ change.

• physical

• chemical