Physical and Chemical Changes

Front

What is a physical change?

Back

A physical change is a change that affects one or more physical properties of a substance without altering its chemical composition. Examples include cutting, bending, or dissolving.

Front

What is a chemical change?

Back

A chemical change is a change that results in the formation of new chemical substances. It involves a chemical reaction and changes the composition of the original substance.

Front

Give an example of a physical change.

Back

Cutting carrots into pieces for a salad is an example of a physical change.

Front

Give an example of a chemical change.

Back

When sodium metal burns in water, it reacts to form sodium hydroxide and hydrogen gas, which is a chemical change.

Front

What happens to the materials in a physical change?

Back

The materials in a physical change do not change their chemical composition; they may change in form or appearance.

Front

What happens to the materials in a chemical change?

Back

In a chemical change, the materials change their chemical composition and form new substances.

Front

What is an indicator of a chemical change?

Back

Indicators of a chemical change include color change, temperature change, gas production, and the formation of a precipitate.

Front

What is an example of a reversible physical change?

Back

Melting ice into water is a reversible physical change.

Front

What is an example of an irreversible chemical change?

Back

Burning wood is an example of an irreversible chemical change.

Front

What is the difference between a physical change and a chemical change?

Back

A physical change does not alter the chemical composition of a substance, while a chemical change does.