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 changes in state (like melting or freezing) and changes in shape or size.

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 the rearrangement of atoms. Examples include burning, rusting, and digestion.

Front

What is an example of a physical change?

Back

Spraying perfume on yourself is an example of a physical change because the chemical composition of the perfume does not change.

Front

What is an example of a chemical change?

Back

Gasoline burning in a car engine is an example of a chemical change because it produces new substances (like carbon dioxide and water) through combustion.

Front

What are some signs that a chemical change has occurred?

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

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What is NOT a sign of a chemical change?

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A loss of transparency is NOT a sign of a chemical change.

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How does a chemical change differ from a physical change?

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A chemical change results in the formation of new substances, while a physical change does not create new substances.

Front

What happens to molecules during a physical change?

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During a physical change, the arrangement of molecules may change, but the molecules themselves remain the same.

Front

What happens to molecules during a chemical change?

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During a chemical change, the bonds between molecules are broken and new bonds are formed, resulting in new substances.

Front

What is an example of a physical change involving temperature?

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An ice pack getting cold after being placed in the freezer is an example of a physical change involving temperature.