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 melting, freezing, and dissolving.

Front

What is a chemical change?

Back

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

Front

Is melting butter a chemical or physical change?

Back

Physical change.

Front

Is burning wood a chemical or physical change?

Back

Chemical change.

Front

What happens to the molecules during a physical change?

Back

The molecules may change their arrangement or state (solid, liquid, gas) but their chemical structure remains the same.

Front

What happens to the molecules during a chemical change?

Back

The molecules rearrange to form new substances with different chemical properties.

Front

What is an example of a physical change?

Back

Dissolving Kool-aid in water.

Front

What is an example of a chemical change?

Back

Burning paper.

Front

What is density?

Back

Density is the mass of a substance divided by its volume, often expressed in grams per milliliter (g/ml).

Front

How can you identify a chemical change?

Back

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