Chm 3.1 Interaction of Energy and Matter - Rate of Reactions and Equilibrium - Chapter

Chm 3.1 Interaction of Energy and Matter - Rate of Reactions and Equilibrium - Chapter 17 and 18

Multiple Choice

Identify the letter of the choice that best completes the statement or answers the question.

____1.To be effective, a collision requires

a. / sufficient energy.
b. / a favorable orientation.
c. / sufficient energy and a favorable orientation.
d. / a reaction mechanism.

____2.If colliding molecules have an orientation that favors reaction, they have

a. / the correct angles and distances between atoms.
b. / sufficient energy for each molecule.
c. / speeds that are neither too fast nor too slow.
d. / entropy values in the proper range.

____3.Raising the temperature of gas particles

a. / increases both collision energy and favorability of orientation.
b. / increases neither collision energy nor favorability of orientation.
c. / increases collision energy but does not increase favorability of orientation.
d. / increases favorability of orientation but does not increase collision energy.

____4.If a collision between molecules is very gentle, the molecules are

a. / more likely to be favorably oriented. / c. / more likely to react.
b. / less likely to be favorably oriented. / d. / more likely to rebound without reacting.

____5.The minimum energy required for an effective collision is called

a. / energy of enthalpy. / c. / free energy.
b. / activation energy. / d. / kinetic energy.

____6.Activation energy is

a. / the energy required to form the activated complex.
b. / the net energy required to turn reactants into products.
c. / the enthalpy of reaction.
d. / free energy.

____7.Raising the temperature of reactants in a system

a. / increases the average kinetic energy of the molecules.
b. / decreases the average kinetic energy of the molecules.
c. / decreases the rate of collision of molecules.
d. / has no effect on the average kinetic energy of molecules.

____8.Raising the temperature of reactants in a system

a. / increases the average molecular motion.
b. / decreases the average molecular motion.
c. / has no effect on the average molecular motion.
d. / disturbs the system so that the collision theory no longer applies.

____9.If a collision between molecules is oriented properly, the molecules are

a. / more likely to react. / c. / less likely to form an intermediate.
b. / more likely to rebound without interacting. / d. / less likely to react.

____10.Which statement correctly describes the energy changes that occur when bonds form and when bonds break?

a. / Breaking bonds is endothermic, and forming bonds is exothermic.
b. / Breaking bonds is exothermic, and forming bonds is endothermic.
c. / Both are exothermic.
d. / Both are endothermic.

____11.For most reactions, particles must

a. / collide. / c. / be at rest.
b. / be properly oriented. / d. / collide in the proper orientation.

____12.How fast something changes with time is a(n)

a. / area. / c. / order.
b. / rate. / d. / collision.

____13.Reaction rate depends upon

a. / both collision frequency and efficiency. / c. / collision efficiency.
b. / average kinetic energy. / d. / average potential energy.

____14.Which of the following affects reaction rate?

a. / the nature of reactants / c. / temperature
b. / surface area of reactants / d. / All of the above

____15.If the surface area of reactants is larger,

a. / the reaction rate is generally higher. / c. / the reaction rate is not affected.
b. / the reaction rate is generally lower. / d. / the rate-determining step is eliminated.

____16.If the concentration of reactants is higher,

a. / the reaction rate is generally higher. / c. / the reaction rate is not affected.
b. / the reaction rate is generally lower. / d. / the rate-determining step is eliminated.

____17.If the temperature of the reactants is lower,

a. / the reaction rate is generally higher. / c. / the reaction rate is not affected.
b. / the reaction rate is generally lower. / d. / the rate-determining step is eliminated.

____18.Changing the temperature affects the rate of reaction because it affects

a. / the energy of the activated complex.
b. / the properties of the reactants.
c. / the enthalpy of reaction.
d. / the frequency of collision and the number of effective collisions.

____19.Which process is used to speed up chemical reactions?

a. / calorimetry / c. / activation
b. / catalysis / d. / inhibition

____20.Catalysts generally affect chemical reactions by

a. / increasing the temperature of the system.
b. / increasing the surface area of the reactants.
c. / providing an alternate pathway with a lower activation energy.
d. / providing an alternate pathway with a higher activation energy.

____21.Catalysts generally affect chemical reactions by

a. / increasing the temperature of the system.
b. / increasing the surface area of the reactants.
c. / providing an alternate pathway with a lower activation energy.
d. / providing an alternate pathway with a higher activation energy.

____22.A reaction in which products can react to re-form reactants is

a. / reforming. / c. / buffered.
b. / reversible. / d. / impossible.

____23.At equilibrium,

a. / all reactions have ceased.
b. / only the forward reaction continues.
c. / only the reverse reaction continues.
d. / both the forward and reverse reactions continue.

____24.At equilibrium,

a. / the forward reaction rate is lower than the reverse reaction rate.
b. / the forward reaction rate is higher than the reverse reaction rate.
c. / the forward reaction rate is equal to the reverse reaction rate.
d. / no reactions take place.

____25.What symbol represents the equilibrium constant?

a. / k / c. / c
b. / K / d. / R

____26.The value of the equilibrium constant for a reaction

a. / changes with concentration. / c. / changes with temperature.
b. / changes with time. / d. / is the same under all conditions.

____27.A very low value of K indicates that

a. / equilibrium is reached slowly. / c. / reactants are favored.
b. / products are favored. / d. / equilibrium has been reached.

____28.A very high value of K indicates that

a. / equilibrium is reached slowly. / c. / reactants are favored.
b. / products are favored. / d. / equilibrium has been reached.

____29.In the equation , what represents the concentrations of the reactants?

a. / [Y] and [Z] / c. /
b. / [W] and [X] / d. /

____30.In the equation, what represents the concentrations of the products?

a. / [Y] and [Z] / c. /
b. / [W] and [X] / d. /

____31.When the chemical equilibrium expression is written, coefficients from the equation for the reaction

a. / appear as coefficients. / c. / appear as subscripts.
b. / appear as exponents. / d. / do not appear.

____32.What is the chemical equilibrium expression for the equation

2A2B + 3CD A4D + C3B2?

a. / / c. /
b. / / d. /

____33.If the system 2CO(g) + O2(g) 2CO2(g) has come to equilibrium and then more CO(g) is added,

a. / [CO2] increases and [O2] decreases. / c. / [CO2] decreases and [O2] decreases.
b. / [CO2] increases and [O2] increases. / d. / both [CO2] and [O2] remain the same.

____34.If the pressure on the equilibrium system 2CO(g) + O2(g) 2CO2(g) is increased,

a. / the quantity of CO(g) increases.
b. / the quantity of CO2(g) decreases.
c. / the quantity of CO2(g) increases.
d. / the quantities in the system do not change.

____35.If the pressure on the equilibrium system N2(g) + O2(g) 2NO(g) decreases,

a. / the quantity of N2(g) decreases.
b. / the quantity of NO(g) increases.
c. / the quantity of NO(g) decreases.
d. / the quantities in the system do not change.

____36.If the temperature of the equilibrium system CH3OH(g) + 101 kJ CO(g) + 2H2(g) increases,

a. / [CH3OH] increases and [CO] decreases.
b. / [CH3OH] decreases and [CO] increases.
c. / [CH3OH] increases and [CO] increases.
d. / the concentrations in the system do not change.

____37.If the temperature of the equilibrium system CH3OH(g) + 101 kJ CO(g) + 2H2(g) increases, K

a. / increases. / c. / increases or decreases.
b. / decreases. / d. / does not change.

Short Answer

38.What factors determine whether a molecule collision produces a reaction?

39.List all of the factors that influence the rate of a chemical reaction.

40.Sulfur dioxide is commonly formed by the burning of fossil fuels. It combines with additional oxygen to form sulfur trioxide. Write an equilibrium expression for the reaction represented by the following equation.

2SO2(g) + O2(g) 2SO3(g)

Chm 3.1 Interaction of Energy and Matter - Rate of Reactions and Equilibrium - Chapter 17 and 18

Answer Section

MULTIPLE CHOICE

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SHORT ANSWER

38.ANS:

A reaction will occur if the species involved in a collision have sufficient energy and if they are oriented correctly towards each other.

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39.ANS:

Factors influencing the rate of a chemical reaction include the temperature, the nature of each reactant, the surface area, the presence of a catalyst or an inhibitor, and the concentration of the reactants.

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40.ANS:

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