Physical and Chemical Changes Fall Exam 2024 Review

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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 changes in state (like melting or boiling), shape, or size.

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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 the rearrangement of atoms. Examples include rusting, burning, and cooking.

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What happens to the temperature during a chemical change?

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In many chemical changes, the temperature can increase or decrease, depending on whether the reaction is exothermic (releases heat) or endothermic (absorbs heat).

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What is an example of a physical change involving water?

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Boiling water is an example of a physical change, as it changes from liquid to gas (steam) without altering its chemical composition.

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What is an example of a chemical change?

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Burning wood is an example of a chemical change, as it transforms the wood into ash, smoke, and gases, creating new substances.

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What is a precipitate?

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A precipitate is a solid that forms and settles out of a liquid mixture during a chemical reaction.

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What is the role of temperature in physical changes?

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Temperature can affect the rate of physical changes, such as melting or boiling, but it does not change the chemical identity of the substance.

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What is an example of a physical change involving a solid?

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Bending a paperclip is an example of a physical change, as it alters the shape of the paperclip without changing its chemical composition.

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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 alter 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 chemical change that produces gas?

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Vinegar reacting with baking soda is an example of a chemical change that produces carbon dioxide gas.