Classification of Substances and Mixtures

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What is a colloid?

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A colloid is a mixture where tiny particles are dispersed throughout a substance but do not settle out. Examples include milk and fog.

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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. An example is table salt (NaCl).

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What is a heterogeneous mixture?

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A heterogeneous mixture is a mixture in which the components are not uniformly distributed, and different parts can be seen. An example is a tossed salad.

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What is a homogeneous mixture?

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A homogeneous mixture is a mixture in which the composition is uniform throughout. An example is lemonade.

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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. All atoms in an element are alike.

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What is a solution?

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A solution is a homogeneous mixture where one substance (the solute) is dissolved in another (the solvent). An example is saltwater.

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What distinguishes a suspension from a colloid?

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In a suspension, the particles are larger and will settle out over time, while in a colloid, the particles remain dispersed.

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What is the Tyndall effect?

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The Tyndall effect is the scattering of light by particles in a colloid or in very fine suspensions.

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What is the difference between a mixture and a compound?

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A mixture is a physical combination of substances that can be separated, while a compound is a chemical combination that cannot be separated by physical means.

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What is an example of a pure substance?

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An example of a pure substance is distilled water, which contains only H2O molecules.