Physical and Chemical Changes

Front

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 includes changes such as rusting, burning, and cooking.

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What is evidence of a chemical change?

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Evidence of a chemical change includes color change, formation of a gas (bubbles), formation of a precipitate, and temperature change.

Front

What happens during a physical change?

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During a physical change, the form of a substance may change, but its chemical identity remains the same.

Front

Is melting ice a physical or chemical change?

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Melting ice is a physical change because it changes from solid to liquid without altering its chemical composition.

Front

What is an example of a chemical change?

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An example of a chemical change is the rusting of iron, where iron reacts with oxygen to form iron oxide.

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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 a sign that a chemical reaction has occurred?

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A sign that a chemical reaction has occurred includes the formation of a gas, such as fizzing or bubbling.

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What is an example of a physical change in nature?

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An example of a physical change in nature is the formation of the Grand Canyon through erosion.

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What is the role of energy in chemical changes?

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Energy is often absorbed or released during a chemical change, which can cause temperature changes in the surroundings.