Science Unit 1-Physical & Chemical Changes

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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.

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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. It involves a chemical reaction and alters the identity of the original substances.

Front

What happens during melting?

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During melting, a solid substance absorbs heat and changes into a liquid state. An example is ice melting into water.

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What is an example of a chemical change?

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An example of a chemical change is fireworks exploding, which produces new substances and energy.

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What is rusting?

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Rusting is a chemical change that occurs when iron reacts with oxygen and moisture in the air, forming iron oxide (rust).

Front

What is an example of a physical change?

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An example of a physical change is sharpening a pencil, where the pencil's shape changes but its chemical composition remains the same.

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What occurs when two substances mix and a chemical change happens?

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When two substances mix and a chemical change occurs, they lose their individual identities and form a new substance.

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

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A physical change does not change the chemical composition of a substance, while a chemical change results in the formation of new substances.

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What is an example of a substance undergoing a physical change?

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An example of a substance undergoing a physical change is water freezing into ice.

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What is an example of a chemical change in everyday life?

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An example of a chemical change in everyday life is baking a cake, where ingredients react to form a new product.