1.1 Chemical and physical properties and 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 the breaking and forming of bonds.

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What is the difference between intensive and extensive properties?

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Intensive properties do not depend on the amount of substance present (e.g., density, color), while extensive properties do depend on the amount of substance (e.g., mass, volume).

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What is an example of a chemical property?

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An example of a chemical property is flammability, which indicates how a substance reacts with oxygen to produce heat and light.

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What is an example of a physical property?

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An example of a physical property is boiling point, which is the temperature at which a substance changes from a liquid to a gas.

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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 rusting an example of?

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Rusting is an example of a chemical change, as it involves the reaction of iron with oxygen to form iron oxide.

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How can you identify a chemical change?

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A chemical change can be identified by the production of gas, color change, temperature change, or the formation of a precipitate.

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What is the significance of observing color in liquids?

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Observing color in liquids is an example of an intensive property, as it does not change regardless of the amount of liquid present.

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What is meant by 'reactivity' in terms of chemical properties?

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Reactivity refers to how readily a substance undergoes a chemical reaction with other substances.