ET -- Physical and Chemical Changes

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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.

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What is a chemical change?

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A chemical change is a change that results in the formation of new chemical substances, involving a rearrangement of atoms.

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What are indicators of a chemical change?

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

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Is boiling water a chemical change?

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No, boiling water is a physical change because it remains water (H2O) in both liquid and gas states.

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What happens to the molecules during a physical change?

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The molecules may change their state or appearance, but their chemical structure remains the same.

Front

What happens to the molecules during a chemical change?

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The molecules rearrange to form new substances with different properties.

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What is an example of a physical change?

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Melting ice is an example of a physical change; the ice changes from solid to liquid but remains H2O.

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What is an example of a chemical change?

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Rusting of iron is an example of a chemical change; iron reacts with oxygen to form iron oxide.

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What is the law of conservation of mass?

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The law states that mass is neither created nor destroyed in a chemical reaction; the total mass of reactants equals the total mass of products.

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What is a precipitate?

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A precipitate is a solid that forms and settles out of a liquid mixture during a chemical reaction.