Physical or Chemical?

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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. It involves a chemical reaction and the breaking and forming of bonds. Examples include rusting, burning, and digestion.

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What are the signs of a chemical change?

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Signs of a chemical change include color change, temperature change, gas production (bubbles), formation of a precipitate, and change in odor.

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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 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 an example of a physical change?

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An example of a physical change is ice melting into water. The substance remains H2O, but its state changes from solid to liquid.

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What is an example of a chemical change?

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An example of a chemical change is the combustion of wood. The wood reacts with oxygen to produce ash, carbon dioxide, and water.

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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. Examples include salad and air.

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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. Examples include distilled water and gold.

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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 carbon.

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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).