TOMS Review: Changes in Matter

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What is a chemical change?

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A chemical change is a process where substances combine or break apart to form new substances with different properties. Examples include burning, rusting, and souring of milk.

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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 compound?

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A compound is a substance formed when two or more elements chemically bond together in a fixed ratio. Examples include water (H2O) and carbon dioxide (CO2).

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What is an element?

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An element is a pure substance that cannot be broken down into simpler substances by chemical means. Examples include hydrogen (H), oxygen (O), and gold (Au).

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What is a mixture?

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A mixture is a combination of two or more substances that are not chemically bonded. The individual substances retain their properties. Examples include air and salad.

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What is the difference between a compound and a mixture?

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A compound is a substance formed from two or more elements chemically bonded together, while a mixture is a combination of substances that are not chemically bonded.

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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, resulting in new substances.

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What is an example of a chemical change?

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An example of a chemical change is burning wood, which produces ash, smoke, and gases, changing the original substance into 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, where the substance changes state but remains H2O.

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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, forming iron oxide (rust).