Which is a sign of a chemical change?

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Multiple Choice

Which is a sign of a chemical change?

A chemical change shows evidence that new substances are forming. The most telling signs are color change, energy released or absorbed (temperature change or light), gas production, and the formation of a precipitate. When you see any of these together, it points to a chemical reaction taking place because the materials are reacting to form something different. The other scenarios describe physical changes rather than chemical ones. A change in shape doesn’t create new substances; dissolving a solid in water is usually just a physical process of separation into ions or molecules in solution, not a new substance formed. If the temperature stays the same and nothing else changes, there’s no chemical reaction occurring.

A chemical change shows evidence that new substances are forming. The most telling signs are color change, energy released or absorbed (temperature change or light), gas production, and the formation of a precipitate. When you see any of these together, it points to a chemical reaction taking place because the materials are reacting to form something different.

The other scenarios describe physical changes rather than chemical ones. A change in shape doesn’t create new substances; dissolving a solid in water is usually just a physical process of separation into ions or molecules in solution, not a new substance formed. If the temperature stays the same and nothing else changes, there’s no chemical reaction occurring.

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