Chemistry Practice Test

Correct answer: A

The correct answer is Atoms are conserved, so each element must have the same count on both sides.

1. Identify the chemistry concept: Determine whether the prompt concerns atomic structure, bonding, reactions, energy, rates, equilibrium, acids and bases, or laboratory reasoning.
2. Use the evidence: Balancing represents conservation of matter without changing the chemical formulas of the substances.
3. Check the model: Confirm that the answer conserves matter and charge and matches the data or chemical relationship described in the question.

Correct answer: B

The correct answer is A relative amount of particles or moles of a substance in the reaction.

1. Identify the chemistry concept: Determine whether the prompt concerns atomic structure, bonding, reactions, energy, rates, equilibrium, acids and bases, or laboratory reasoning.
2. Use the evidence: Coefficients provide proportional relationships among reacting and produced amounts.
3. Check the model: Confirm that the answer conserves matter and charge and matches the data or chemical relationship described in the question.

Correct answer: C

The correct answer is Converting between amounts of substances using coefficients in a balanced equation.

1. Identify the chemistry concept: Determine whether the prompt concerns atomic structure, bonding, reactions, energy, rates, equilibrium, acids and bases, or laboratory reasoning.
2. Use the evidence: Balanced-equation coefficients establish stoichiometric relationships between substances.
3. Check the model: Confirm that the answer conserves matter and charge and matches the data or chemical relationship described in the question.

Correct answer: D

The correct answer is The reactant consumed first that limits the amount of product formed.

1. Identify the chemistry concept: Determine whether the prompt concerns atomic structure, bonding, reactions, energy, rates, equilibrium, acids and bases, or laboratory reasoning.
2. Use the evidence: Once the limiting reactant is used up, the reaction cannot form more product under those conditions.
3. Check the model: Confirm that the answer conserves matter and charge and matches the data or chemical relationship described in the question.

Correct answer: A

The correct answer is It connects mass measurements to amounts in moles.

1. Identify the chemistry concept: Determine whether the prompt concerns atomic structure, bonding, reactions, energy, rates, equilibrium, acids and bases, or laboratory reasoning.
2. Use the evidence: Molar mass allows conversion between grams and moles for quantitative chemical reasoning.
3. Check the model: Confirm that the answer conserves matter and charge and matches the data or chemical relationship described in the question.

Correct answer: B

The correct answer is A reaction involving transfer of electrons or changes in oxidation states.

1. Identify the chemistry concept: Determine whether the prompt concerns atomic structure, bonding, reactions, energy, rates, equilibrium, acids and bases, or laboratory reasoning.
2. Use the evidence: Redox reactions track electron loss and gain between substances.
3. Check the model: Confirm that the answer conserves matter and charge and matches the data or chemical relationship described in the question.

Correct answer: C

The correct answer is The actual amount of product with the theoretical amount predicted by the reaction.

1. Identify the chemistry concept: Determine whether the prompt concerns atomic structure, bonding, reactions, energy, rates, equilibrium, acids and bases, or laboratory reasoning.
2. Use the evidence: Percent yield describes how the measured product compares with the maximum predicted under the model.
3. Check the model: Confirm that the answer conserves matter and charge and matches the data or chemical relationship described in the question.

Correct answer: D

The correct answer is A reaction in solution that forms an insoluble solid.

1. Identify the chemistry concept: Determine whether the prompt concerns atomic structure, bonding, reactions, energy, rates, equilibrium, acids and bases, or laboratory reasoning.
2. Use the evidence: A precipitate is a solid product that separates from a solution because it is not sufficiently soluble.
3. Check the model: Confirm that the answer conserves matter and charge and matches the data or chemical relationship described in the question.

Correct answer: A

The correct answer is The products have lower chemical potential energy than the reactants, with energy transferred to surroundings.

1. Identify the chemistry concept: Determine whether the prompt concerns atomic structure, bonding, reactions, energy, rates, equilibrium, acids and bases, or laboratory reasoning.
2. Use the evidence: Energy changes reflect rearranged interactions and can transfer between a reaction system and surroundings.
3. Check the model: Confirm that the answer conserves matter and charge and matches the data or chemical relationship described in the question.

Correct answer: B

The correct answer is The total mass of reactants equals the total mass of products in a closed system.

1. Identify the chemistry concept: Determine whether the prompt concerns atomic structure, bonding, reactions, energy, rates, equilibrium, acids and bases, or laboratory reasoning.
2. Use the evidence: Atoms are rearranged, so total mass remains constant when the system is accounted for.
3. Check the model: Confirm that the answer conserves matter and charge and matches the data or chemical relationship described in the question.