Final Assessment: Chemistry

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What is the law of conservation of mass?

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The law of conservation of mass states that mass cannot be created or destroyed in a chemical reaction. The total mass of reactants equals the total mass of products.

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What is a physical change?

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A physical change is a change that affects one or more physical properties of a substance without altering its chemical composition. Examples include melting, freezing, and dissolving.

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What is a chemical change?

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A chemical change is a change that results in the formation of new chemical substances. Indicators include color change, gas production, and temperature change.

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What happens when ice melts?

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When ice melts, it undergoes a physical change from solid to liquid, and the mass remains the same.

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What is a compound?

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A compound is a substance formed when two or more elements chemically bond together in fixed proportions.

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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, oxygen, and gold.

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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. Each substance retains its own properties.

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What is an example of a chemical reaction?

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An example of a chemical reaction is the reaction between baking soda and vinegar, which produces carbon dioxide gas.

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What is the difference between a physical change and a chemical change?

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A physical change does not alter the chemical composition of a substance, while a chemical change results in the formation of new substances.

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What is density?

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Density is the mass of a substance divided by its volume, often expressed in grams per cubic centimeter (g/cm³).