Physical and Chemical Properties and Changes

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What is a chemical change?

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A process where substances combine or break apart to form new substances, often accompanied by signs like color change, gas formation, or temperature change.

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What is a physical change?

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A change that affects one or more physical properties of a substance without altering its chemical composition, such as melting or freezing.

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What are signs of a chemical reaction?

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

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What is density?

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Density is the mass of a substance divided by its volume, often used to identify substances.

Front

Is rusting an example of a physical or chemical change?

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Rusting is a chemical change because it involves the reaction of iron with oxygen to form iron oxide.

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What happens to the molecules during a physical change?

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The molecules rearrange but do not change their chemical structure.

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What is an example of a physical change?

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Examples include melting ice, boiling water, or breaking a glass.

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What is an example of a chemical change?

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Examples include burning wood, baking a cake, or rusting iron.

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

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Physical properties can be observed without changing the substance (e.g., color, melting point), while chemical properties describe how a substance reacts with others (e.g., flammability, reactivity).

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What does it mean if a change is reversible?

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A reversible change is one that can be undone, such as freezing and melting water.