Chemical and Physical 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 melting, freezing, and shredding.

Front

What is a chemical change?

Back

A chemical change is a change that results in the formation of new chemical substances. Examples include rusting, burning, and cooking.

Front

Can a physical change be undone?

Back

Yes, a physical change can often be undone. For example, ice can melt and then be refrozen.

Front

Can a chemical change be undone?

Back

No, a chemical change usually cannot be undone. For example, burning wood turns it into ash, which cannot be changed back to wood.

Front

What happens to the weight of matter during a chemical change?

Back

The weight of matter stays the same during a chemical change, as mass is conserved.

Front

What happens to the weight of matter during a physical change?

Back

The weight of matter stays the same during a physical change, as mass is conserved.

Front

Give an example of a physical change.

Back

An example of a physical change is ice melting into water.

Front

Give an example of a chemical change.

Back

An example of a chemical change is copper roof changing color due to oxidation.

Front

What is an example of a reversible physical change?

Back

An example of a reversible physical change is freezing water to make ice.

Front

What is an example of an irreversible chemical change?

Back

An example of an irreversible chemical change is baking a cake.