Understanding Chemical Reactions and Conservation

• 2 oxygen atoms in reactants, 1 oxygen atom in products; matter is not conserved.

• 2 oxygen atoms in reactants, 2 oxygen atoms in products; matter is conserved.

• 1 oxygen atom in reactants, 2 oxygen atoms in products; matter is not conserved.

• 4 oxygen atoms in reactants, 2 oxygen atoms in products; matter is conserved.

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• Propane reacts with oxygen to form carbon dioxide and water.

• Methane reacts with oxygen to form carbon monoxide and water.

• Ethane reacts with oxygen to form carbon dioxide and hydrogen gas.

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Explain why mass may appear to be lost in an open system during a chemical reaction.

• Mass is converted into energy and disappears.

• Mass is absorbed by the reactants and becomes invisible.

• Mass is released to the surrounding environment and is not measured in the products.

• Mass is destroyed during the reaction.

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• 4 iron atoms in reactants, 4 iron atoms in products; matter is conserved.

• 2 iron atoms in reactants, 4 iron atoms in products; matter is not conserved.

• 4 iron atoms in reactants, 2 iron atoms in products; matter is not conserved.

• 3 iron atoms in reactants, 3 iron atoms in products; matter is conserved.

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• Two hydrogen molecules and one oxygen molecule on the reactant side; two water molecules on the product side.

• One hydrogen molecule and two oxygen molecules on the reactant side; two water molecules on the product side.

• Two hydrogen molecules and two oxygen molecules on the reactant side; one water molecule on the product side.

• One hydrogen molecule and one oxygen molecule on the reactant side; one water molecule on the product side.

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• 6 oxygen atoms in reactants, 6 oxygen atoms in products; matter is conserved.

• 3 oxygen atoms in reactants, 6 oxygen atoms in products; matter is not conserved.

• 6 oxygen atoms in reactants, 3 oxygen atoms in products; matter is not conserved.

• 4 oxygen atoms in reactants, 4 oxygen atoms in products; matter is conserved.

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Explain how the coefficients in a balanced chemical equation relate to the conservation of matter.

• Coefficients indicate the number of molecules, ensuring that the same number of atoms are present on both sides of the equation.

• Coefficients indicate the mass of each substance, ensuring that mass is conserved.

• Coefficients indicate the volume of each substance, ensuring that volume is conserved.

• Coefficients indicate the energy of each substance, ensuring that energy is conserved.

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• 6 carbon atoms in reactants, 6 carbon atoms in products; matter is conserved.

• 12 carbon atoms in reactants, 6 carbon atoms in products; matter is not conserved.

• 6 carbon atoms in reactants, 12 carbon atoms in products; matter is not conserved.

• 3 carbon atoms in reactants, 3 carbon atoms in products; matter is conserved.

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• Nitrogen reacts with hydrogen to form ammonia.

• Nitrogen reacts with oxygen to form nitric acid.

• Nitrogen reacts with water to form ammonium hydroxide.

• Nitrogen reacts with carbon to form cyanide.

What happens to the atoms of the reactants in a chemical reaction?

• They change into new atoms.

• They change names.

• Some are lost to the environment.

• They recombine to form new products.

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