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 cannot be reversed by simple physical means. Examples include rusting, burning, and baking.

Front

What is an example of a physical change?

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Melting of ice, dissolving sugar in water, or breaking a glass.

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What is an example of a chemical change?

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Baking cookies, burning wood, or rusting of iron.

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What are some signs of a chemical change?

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

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Why is dissolving candy considered a physical change?

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Dissolving candy is a physical change because a new substance is NOT formed, and the process can be reversed.

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What happens to the properties of a substance during a physical change?

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The properties of a substance may change (like shape or state), but its chemical identity remains the same.

Front

What happens to the properties of a substance during a chemical change?

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The properties of a substance change, and a new substance is formed with different chemical properties.

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What is an example of a sign that a chemical reaction has occurred?

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Formation of a gas, such as bubbles during a reaction.

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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).