Understanding Physical and Chemical Changes

What is a characteristic of a physical change?

• It always involves heat.

• It produces a new substance.

• It alters the appearance or phase.

• It changes the chemical composition.

Which of the following is an example of a chemical change?

• Cutting paper

• Burning toast

• Boiling water

• Melting ice

What is a sign that a chemical change has occurred?

• The substance changes color.

• The substance becomes colder.

• The substance changes shape.

• The substance remains the same.

Why is it important to understand the difference between physical and chemical changes?

• To predict the weather

• To understand the properties of substances

• To create new elements

• To measure mass accurately

What happens to the molecules in a physical change?

• They disappear.

• They become larger.

• They rearrange but keep the same structure.

• They form new chemical bonds.