8.5E - 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 dissolving.

Front

What is a chemical change?

Back

A chemical change is a process that involves the transformation of one or more substances into different substances, resulting in the formation of new chemical compounds. Examples include burning, rusting, and digestion.

Front

What is an example of a physical change?

Back

Dissolving sugar in warm water is an example of a physical change.

Front

What is an example of a chemical change?

Back

Burning sugar, which gives off an odor and changes color, is an example of a chemical change.

Front

What evidence indicates a chemical reaction has occurred?

Back

Evidence of a chemical reaction includes color change, gas production, temperature change, and the formation of a precipitate.

Front

What happens to the temperature during a chemical change?

Back

A change in temperature can indicate a chemical change, as energy is either absorbed or released during the reaction.

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 results in the formation of new substances.

Front

What is an example of a physical change involving a solid?

Back

Getting a haircut is an example of a physical change involving a solid (hair).

Front

What is rusting an example of?

Back

Rusting is an example of a chemical change, as it involves the reaction of iron with oxygen to form iron oxide.

Front

What is the role of energy in chemical changes?

Back

Energy is either absorbed or released during chemical changes, which can result in temperature changes.