Physical and Chemical Changes

Front

What is a physical change?

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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?

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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 are indicators 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 are indicators of a physical change?

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Indicators of a physical change include changes in state (solid, liquid, gas), shape, size, and texture without altering the substance's chemical identity.

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Can a physical change be reversed?

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Yes, many physical changes can be reversed, such as freezing and melting water.

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Can a chemical change be reversed?

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Most chemical changes are not easily reversible, as they result in new substances. However, some chemical reactions can be reversed under certain conditions.

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What happens to the mass of substances during a chemical change?

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The mass of substances is conserved during a chemical change; it remains the same before and after the reaction, according to the law of conservation of mass.

Front

What happens to the mass of substances during a physical change?

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The mass of substances remains unchanged during a physical change, as no new substances are formed.

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Give an example of a physical change.

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An example of a physical change is ice melting into water.

Front

Give an example of a chemical change.

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An example of a chemical change is iron rusting when exposed to oxygen and moisture.