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. It can be an element or a compound.

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What is the difference between an element and a compound?

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An element is a pure substance that cannot be broken down into simpler substances by chemical means, while a compound is a substance formed when two or more elements chemically bond together.

Front

What is a mixture?

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A mixture is a combination of two or more substances that are not chemically bonded and can be separated by physical means.

Front

What is a homogeneous mixture?

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A homogeneous mixture is a mixture that has a uniform composition and appearance throughout, such as steel or saltwater.

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What is a heterogeneous mixture?

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A heterogeneous mixture is a mixture that has a non-uniform composition, where the different components can be seen and separated, such as salad or sand.

Front

What are atoms?

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Atoms are the basic building blocks of matter, consisting of a nucleus made of protons and neutrons, surrounded by electrons.

Front

What is the law of conservation of mass?

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The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction; it is conserved.

Front

What is a chemical formula?

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A chemical formula is a symbolic representation of a compound, indicating the elements present and the number of atoms of each element.

Front

What does the subscript in a chemical formula represent?

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The subscript in a chemical formula indicates the number of atoms of the element that precedes it in a molecule.

Front

What is the significance of the coefficient in a chemical equation?

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The coefficient in a chemical equation indicates the number of molecules or moles of a substance involved in the reaction.