Elements, Compounds and Mixtures — Flashcards

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An element is a pure substance which cannot be converted into anything simpler than itself by any physical or chemical process. It is made up of only one kind of atoms. The smallest unit of an element…

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A compound is a pure substance composed of two or more elements combined chemically in a definite proportion by mass. The smallest unit of a compound is a molecule. Example: water, sodium chloride.

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A mixture is an impure substance formed by mixing two or more pure substances in any proportion without chemical change. The components retain their individual properties. Mixtures can be homogeneous …

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Elements are made of one kind of atoms. Compounds are formed when two or more elements combine chemically in a fixed ratio. Mixtures are formed by physical mixing in any ratio and have no fixed compos…

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Hydrogen and chlorine combine to form hydrogen chloride. Balanced equation: H2 + Cl2 → 2HCl This is a chemical reaction that forms a compound from two elements.

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Balanced equation: 2K + 2H2O → 2KOH + H2 Potassium reacts with water to form potassium hydroxide and hydrogen gas. This is a chemical reaction between an element and a compound.

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Sodium is a soft and highly reactive metal. Chlorine is a poisonous greenish yellow gas with choking smell. Sodium chloride is a white crystalline solid, non-poisonous and useful. A compound has prope…

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Water is H2O. It is formed from hydrogen and oxygen in a 1:8 ratio by mass. Water is a liquid at ordinary temperature, neither combustible nor a supporter of combustion.