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 baking.

Front

What happens to iron when it rusts?

Back

When iron rusts, it undergoes a chemical change due to a reaction with oxygen and moisture, forming iron oxide (rust).

Front

What is an example of a chemical reaction?

Back

Lighting a match is an example of a chemical reaction, as it produces heat and light and forms new substances.

Front

What is an example of a physical change?

Back

Melting a chocolate bar is an example of a physical change, as it changes the state of the chocolate without altering its chemical structure.

Front

What is the difference between physical and chemical changes?

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Physical changes do not create new substances and can often be reversed, while chemical changes create new substances and are usually irreversible.

Front

What is rusting?

Back

Rusting is a chemical change that occurs when iron reacts with oxygen and moisture in the environment, leading to the formation of rust.

Front

What is an indicator of a chemical change?

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

Front

What is an example of a substance that undergoes a chemical change when heated?

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Baking soda (sodium bicarbonate) undergoes a chemical change when heated, producing carbon dioxide gas and sodium carbonate.

Front

What is a common physical change that occurs when water freezes?

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When water freezes, it undergoes a physical change from liquid to solid, but its chemical composition (H2O) remains the same.