Chemical and physical changes

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What is a chemical change?

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A process where one or more substances are transformed into new substances with different properties.

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What is a physical change?

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A change that affects one or more physical properties of a substance without altering its chemical composition.

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What happens to iron when it rusts?

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It undergoes a chemical change, forming a new substance (rust) when exposed to air and moisture.

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What is an example of a physical change?

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Melting ice into water; the substance remains H2O.

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What is an example of a chemical change?

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Burning wood in a campfire; it transforms into ash and gases.

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What is the difference between a physical change and a chemical change?

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Physical changes do not create new substances, while chemical changes do.

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What is an example of a reversible physical change?

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Freezing and melting water; it can change back to its original state.

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What is an example of an irreversible chemical change?

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Baking a cake; once baked, the ingredients cannot be returned to their original state.

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What is meant by 'new substance' in a chemical change?

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A substance that has different properties from the original substances involved in the change.

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What is an indicator of a chemical change?

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Color change, gas production, or temperature change.