How Do Reactants Change During a Reaction?

Which of these is true of chemical reactions?

• In a chemical reaction, one or more substances undergo a change in state.

• In a chemical reaction, the substances that are combined always form a gas.

• In a chemical reaction, one or more new substances are formed from one or more other substances.

• All of the above.

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Reactants are substances that

• esists after a reaction.

• change as a result of the reaction.

• change "states" as a result of the reaction.

• are the parts of the substances left over after a chemical reaction.

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In a chemical reaction, a product is

• the substance that exists before the chemical reaction.

• the gas that always forms as a result of the chemical reaction.

• a different substance than the substance from which it came.

• a property used to identify substances in a chemical reaction.

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Acetic acid and sodium bicarbonate combine to form water, sodium acetate, and carbon dioxide. Which are the reactant(s)?

• acetic acid and sodium bicarbonate

• acetic acid and sodium acetate

• water, sodium acetate, and carbon dioxide

• water, sodium bicarbonate, and carbon dioxide

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How are scientists able to tell the difference between reactants and products?

• Scientists watch the chemical reaction take place.

• Scientists look for the vivid yellow color in a liquid or solid product.

• Scientists use a table that tells them the products of all possible chemical reactions.

• Scientists compare the properties of the products to the properties of the reactants.

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Which of these is NOT a property that scientists use to identify a substance?

• density

• flammability

• odor

• surface area

Chemical properties are

• the steps of a chemical reaction from beginning to end.

• properties of matter that are only noticeable when thermal energy is applied.

• properties of substances that are not related to their physical appearance.

• properties of matter that are only noticeable during or after a chemical reaction.

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Which of these is a chemical property of a substance?

• the ability to change products back into reactants

• the ability to react with another substance

• the amount of a new substance formed from a chemical reaction

• the state change that a substance undergoes as a result of a chemical reaction

What determines whether a reactant undergoes a chemical reaction?

• the ability of the reactant to change state during the chemical reaction

• the flammability of the reactants prior to the chemical reaction

• the number of reactants that are involved in a chemical reaction

• the reactant’s chemical properties and specific conditions

Which of these actions is an example of energy being applied to a chemical reaction?

• chilling water to make ice

• striking a match-head to produce a flame

• applying salt to ice to lower the water’s freezing point

• mixing baking soda and vinegar to make a new substance

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