Chapter 7 Review

both reactants and products include an element and a compound.

A key feature of a single-replacement reaction is that a. a single reactant becomes two or more products. b. both reactants and products include an element and a compound. c. two compounds swap ions, producing two new compounds. d. two or more reactants become a single product.

exothermic

Chemical reactions that give off heat are called __________ reactions. a. catalytic c. endothermic b. conservation d. exothermic

by lowering the activation energy

How does a catalyst increase a reaction rate? a. by increasing the concentration of the reactants b. by increasing the number of collisions c. by lowering the activation energy d. by lowering the surface area

a single reactant becomes two or more products.

The key feature of a decomposition reaction is that a. a single reactant becomes two or more products. b. both reactants and products include an element and a compound. c. two compounds swap ions, producing two new compounds. d. two or more reactants become a single product.

The forward and reverse reactions both continue to occur at the same rate.

What happens to the forward and reverse reactions when a system reaches its equilibrium state? a. Both the forward and reverse reactions stop. b. The forward and reverse reactions both continue to occur at the same rate. c. The forward reaction stops and the reverse reaction continues to occur. d. The reverse reaction stops and the forward reaction continues to occur.

a quantity

What is a mole? a. an equation c. a quantity b. a mass d. a ratio

decomposition

What kind of reaction occurs when water breaks up into hydrogen and oxygen gas? a. decomposition c. single-replacement b. double-replacement d. synthesis

an inhibitor

Which of the following decreases the rate of a reaction? a. a catalyst c. an inhibitor b. an enzyme d. a reduction

Some energy is destroyed by combustion.

Which of the following does not happen to the energy given off by a campfire? a. Some energy is absorbed by the environment. c. Some energy is given off as thermal energy. b. Some energy is given off as light energy. d. Some energy is destroyed by combustion.

a change in size

Which of the following is not evidence that a chemical change has occurred? a. a change in color c. a distinct smell b. a change in size d. a change in temperature

Catalysts must be present to increase the reaction rate.

Which of the following is not part of the collision model for affecting reaction rates? a. Catalysts must be present to increase the reaction rate. b. Enough energy must be present. c. Reactant particles must be aligned properly. d. Reactant particles must collide.

both A and B

Which of the following occur(s) in a redox reaction? a. An element loses electrons. c. both A and B b. An element gains electrons. d. neither A nor B

combustion

Which of the following reactions require(s) the presence of oxygen? a. combustion c. both A and B b. oxidation d. neither A nor B

dividing a large reactant into smaller pieces

Which of the following would most likely increase the reaction rate of a chemical reaction? a. dividing a large reactant into smaller pieces b. lowering the temperature c. preventing any stirring from occurring d. reducing the concentration of the reactants

shifts the reaction toward the side of the equation that releases energy.

Decreasing the temperature of a system that has reached chemical equilibrium a. causes the reactions to stop altogether. b. shifts the reaction toward the side of the equation that absorbs energy. c. shifts the reaction toward the side of the equation that releases energy. d. does not affect equilibrium.

any reaction where electrons are lost.

The term oxidation is used today to refer to a. any reaction that burns. c. fuel reacting with oxygen. b. any reaction where electrons are lost. d. reactions between metals and oxygen.