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. It involves a chemical reaction and includes processes like burning, rusting, and digestion.

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 iron rusting when it reacts with oxygen.

Front

What happens to the molecules during a physical change?

Back

During a physical change, the molecules rearrange but do not change their chemical structure.

Front

What happens to the molecules during a chemical change?

Back

During a chemical change, the molecules break apart and recombine to form new substances.

Front

Is dissolving sugar in water a physical or chemical change?

Back

Dissolving sugar in water is a physical change because the sugar can be recovered by evaporating the water.

Front

Is burning wood a physical or chemical change?

Back

Burning wood is a chemical change because it produces ash, smoke, and gases, which are different substances.

Front

What is a sign that a chemical change has occurred?

Back

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

Front

Can physical changes be reversed?

Back

Many physical changes can be reversed, such as freezing and melting, but some may not be easily reversible.