Law of conservation of mass

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What is the Law of Conservation of Mass?

Back

The Law of Conservation of Mass states that in a closed system, the mass of the reactants must equal the mass of the products in a chemical reaction.

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What evidence supports the Law of Conservation of Mass during a chemical reaction?

Back

The total mass of the reactants before the reaction is equal to the total mass of the products after the reaction.

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What does it mean for a chemical reaction to be balanced?

Back

A chemical reaction is balanced when both sides have the same number of atoms of each element.

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What is a coefficient in a chemical equation?

Back

A coefficient is a number placed in front of a compound or element in a chemical equation to indicate how many molecules or moles are involved.

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What is a subscript in a chemical formula?

Back

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

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True or False: Gases produced in a chemical reaction do not need to be accounted for in mass calculations.

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False. Gases have mass and must be included in mass calculations.

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What happens to the number of atoms during a chemical reaction?

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The number of atoms remains the same; they are rearranged to form new substances.

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How can you determine if a chemical equation is balanced?

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Count the number of atoms of each element on both sides of the equation; they must be equal.

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What is the role of reactants in a chemical reaction?

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

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What are products in a chemical reaction?

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