Property Changes in Chemical Reactions

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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. Signs of a chemical change include color change, gas formation, and temperature change.

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What are reactants?

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Reactants are the starting substances in a chemical reaction that undergo change to form products.

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What are products?

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Products are the substances that are formed as a result of a chemical reaction.

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What is a coefficient in a chemical equation?

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A coefficient is a number placed in front of a chemical formula in a chemical equation to indicate how many molecules or moles of that substance are involved in the reaction.

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What is a subscript in a chemical formula?

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A subscript is a number written below and to the right of a chemical symbol in a formula, indicating the number of atoms of that element in a molecule.

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What is an example of a sign that a chemical reaction has occurred?

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Formation of a gas is a sign that a chemical reaction has occurred.

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What happens to the properties of substances during a chemical change?

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The properties of substances change during a chemical change, resulting in the formation of new substances with different properties.

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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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Can a physical change be reversed?

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Many physical changes can be reversed, such as freezing and melting, but some may not be easily reversible.