7.6A Changes in Matter

Front

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. Examples include melting, freezing, and dissolving.

Front

What is a chemical change?

Back

A chemical change is a change that results in the formation of new chemical substances. It involves breaking and forming bonds between atoms. Examples include rusting, burning, and digestion.

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What are the signs of a chemical change?

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Signs of a chemical change include color change, temperature change, gas production (bubbles), formation of a precipitate, and change in odor.

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What is the difference between physical and chemical changes?

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Physical changes do not change the substance's chemical identity, while chemical changes do. Physical changes can often be reversed, whereas chemical changes usually cannot.

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What is an example of a physical change in the kitchen?

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Melting butter is an example of a physical change, as it changes from solid to liquid but remains butter.

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What is an example of a chemical change in food?

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Baking a cake is an example of a chemical change, as the ingredients undergo a chemical reaction to form a new substance.

Front

What role do teeth play in digestion?

Back

Teeth break food into smaller pieces, which is a physical change that helps in the digestive process.

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What is digestion?

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Digestion is the process by which food is broken down into smaller components that can be absorbed by the body. It involves both physical and chemical changes.

Front

What happens during chemical digestion?

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During chemical digestion, enzymes break down food into simpler molecules, such as carbohydrates into sugars.

Front

What is an example of a physical change in nature?

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The melting of ice into water is an example of a physical change that occurs in nature.