Elements, Compounds and Mixtures

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What is a pure substance?

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A pure substance is a material that has a constant composition and consistent properties throughout. Examples include elements and compounds.

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What is a mixture?

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A mixture is a combination of two or more substances where each retains its own properties. Mixtures can be homogeneous or heterogeneous.

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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 copper (Cu).

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What is a compound?

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A compound is a substance formed when two or more elements chemically combine in a fixed ratio. Examples include water (H2O) and table salt (NaCl).

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What is the difference between a homogeneous mixture and a heterogeneous mixture?

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A homogeneous mixture has a uniform composition throughout (e.g., salt water), while a heterogeneous mixture has a non-uniform composition (e.g., salad).

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What happens when elements combine chemically?

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When elements combine chemically, they form compounds with new properties that are different from the individual elements.

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What is an example of a pure substance?

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A balloon filled with helium is an example of a pure substance.

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What is an example of a mixture?

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Sugar crystals dissolving in water is an example of a mixture.

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What is the chemical formula for water?

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The chemical formula for water is H2O.

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What is the process of electrolysis?

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Electrolysis is a chemical process that uses electricity to break down compounds into their elements, such as splitting water into hydrogen and oxygen.