8th grade chemistry

Front

What is a chemical change?

Back

A chemical change is a process where substances combine or break apart to form new substances with different properties, such as cooking an egg or burning wood.

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What is a physical change?

Back

A physical change is a change that affects one or more physical properties of a substance without altering its chemical composition, such as melting butter or tearing paper.

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What is a compound?

Back

A compound is a substance formed when two or more elements chemically bond together in a fixed ratio, such as sugar (C12H22O11).

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What is an element?

Back

An element is a pure substance that cannot be broken down into simpler substances by chemical means, identified by its number of protons.

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What is the Law of Conservation of Mass?

Back

The Law of Conservation of Mass states that mass is neither created nor destroyed in a chemical reaction; the total mass of reactants equals the total mass of products.

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What is a balanced chemical equation?

Back

A balanced chemical equation has the same number of each type of atom on both sides of the equation, reflecting the Law of Conservation of Mass.

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What is the atomic number?

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The atomic number is the number of protons in the nucleus of an atom, which determines the element's identity.

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What is a reactant?

Back

A reactant is a substance that undergoes a chemical change in a reaction, found on the left side of a chemical equation.

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What is a product?

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A product is a substance formed as a result of a chemical reaction, found on the right side of a chemical equation.

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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 and can be separated by physical means, such as air or salad.