Elements, Compounds, Mixtures

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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 compound?

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

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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. Examples include air (a mixture of gases) and salad (a mixture of vegetables).

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How can you classify brass?

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Brass is classified as a mixture because it is made by combining zinc and copper without a chemical reaction.

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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. It can be an element or a compound.

Front

What is the chemical formula for potassium sulfate?

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The chemical formula for potassium sulfate is K₂SO₄.

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How many atoms are in the compound K₂SO₄?

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There are 7 total atoms in K₂SO₄ (2 potassium, 1 sulfur, and 4 oxygen).

Front

What is the symbol for potassium?

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The symbol for potassium is K.

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What distinguishes a compound from a mixture?

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A compound is formed by a chemical reaction and has a fixed ratio of elements, while a mixture is a physical combination of substances that can vary in composition.

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What is a homogeneous mixture?

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A homogeneous mixture is a mixture that has a uniform composition throughout, such as saltwater.