Chemical and Physical 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 tearing.

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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 includes processes like burning, rusting, and baking.

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What happens when a chocolate bar melts?

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Melting a chocolate bar is a physical change because it changes the state of the chocolate from solid to liquid without changing its chemical structure.

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What is an example of a chemical change?

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An example of a chemical change is the reaction between baking soda and vinegar, which produces carbon dioxide gas.

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What is evidence of a physical change?

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Evidence of a physical change includes changes in shape, size, or state of matter, such as melting ice or ripping paper.

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What is evidence of a chemical change?

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Evidence of a chemical change includes the formation of a new substance, color change, temperature change, gas production, or the release of light.

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

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A physical reaction involves changes in physical properties without altering the substance's chemical structure, while a chemical reaction involves the formation of new substances.

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What is an example of a physical change?

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An example of a physical change is ripping up paper, which changes its shape but not its chemical composition.

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What does it mean when a change causes a temperature change?

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A temperature change typically indicates a chemical reaction has occurred, as energy is either absorbed or released during the reaction.

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What is the definition of a substance?

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A substance is a form of matter that has a specific chemical composition and distinct properties.