Physical and Chemical 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 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 is usually not reversible. Examples include rusting, burning, and baking.

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What are signs of a chemical change?

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

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What is rusting?

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Rusting is a chemical change that occurs when iron reacts with oxygen and moisture in the air, forming iron oxide (rust).

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What happens during a chemical reaction?

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During a chemical reaction, reactants are transformed into products through the breaking and forming of chemical bonds.

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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 physical change?

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An example of a physical change is ice melting into water.

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What is an example of a chemical change?

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An example of a chemical change is baking cookies, where ingredients undergo a chemical reaction to form a new product.

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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, returning the substance to its original state, such as freezing and melting water.

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What does it mean if a change is irreversible?

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An irreversible change is one that cannot be undone, resulting in the formation of new substances, such as burning wood.