Free Printable Exam II Practice Chemical Kinetics and Equilibrium

1.

Limestone chunks are reaction with hydrochloric acid solution at constant temperature with average speed. If we crash the chunks of limestone into powder how would speed of reaction change?

a)

Reaction speeds up

b)

Reaction does not change

c)

Reaction slows down

d)

Reaction stops

2.

Which of the following is NOT a factor affecting reaction rate?

a)

temperature

b)

catalysts

c)

particle size

d)

polarity

3.

Reaction rate means...

a)

amount of product formed

b)

speed of reaction

c)

concentration of reacting particles

d)

combining reactants with products

4.

Decreasing the particle size increases the reaction rate because

a)

It makes particles move faster

b)

It increases the likelihood of collisions with the correct geometry

c)

It decreases the surface area available to react

d)

It increases the number of collisions

5.

To slow down a chemical reaction you will do one of the following:

a)

Place the reactants in hot water

b)

Place the products in ice bath

c)

Place the reactants in a ice bath

d)

Keep stirring the reactants with a stirring rod

6.

The catalyst alters the rate of a chemical reaction by,

a)

providing an alternative pathway with a lower Ea

b)

changing the products formed in the direction of the reaction

c)

providing a surface on which the molecules react

d)

increasing the frequencies of collisions between molecules

7.

Which of the following are true of reaction rates?

I. The overall rate law is determined by the fastest step of a reaction

II. The presence of a catalyst will increase the number of molecules entering the transition state

III. An increase in temperature will increase the rate of a reaction

IV. Decreasing the concentration of reactants will increase the rate at which products yield

a)

II+III+IV

b)

I+IV

c)

II + III

d)

I+II+III

8.

Which factors increase the rate of a reaction?

a)

increasing temperature

b)

increasing concentration

c)

increasing surface area

d)

all of the above

9.

What letter represents the activation energy?

a)

A

b)

B

c)

C

d)

D

10.

Usually lowering the temperature will slow down a reaction.

a)

false

b)

true

11.

Catalysts permit reactions to happen with a __________ activiation energy.

a)

lower

b)

higher

12.

What type of reaction is this?

a)

Endothermic

b)

Exothermic

13.

What are the two criteria for a collision to be effective?

a)

proper orientation and particle size

b)

enough energy to overcome the activation energy and proper orientation

c)

enough energy to overcome the activation energy and homogeneity

d)

proper orientation and heterogeneity

14.

More collisions correspond to a:

a)

Faster reaction rate

b)

Slower reaction rate

c)

Constant reaction rate

d)

None of the above

15.

Based on the collision model, the atoms in the top of potential energy ‘’hill’’ are called

a)

Top of hill

b)

Activation energy

c)

Transition state

d)

Steric factor

16.

Which of the following best describes why increasing temperature increase reaction rate?

a)

Activation energy is reduced.

b)

Collisions become more frequent.

c)

Collisions become more energetic.

d)

Collisions become more frequent and more energetic.

17.

Which of the following statements about the catalyst is true?

a)

A catalyst accelerates the rate of reaction by bringing down the activation energy.

b)

A catalyst does not participate in reaction mechanism.

c)

A catalyst makes the reaction feasible by making ∆G more negative.

d)

A catalyst makes equilibrium constant more favorable for forward reaction.

18.

An endothermic reaction with high activation energy for the forward reaction is given by the diagram.

a)

A

b)

B

c)

C

d)

D

19.

To measure rate of reaction, we can monitor change in which of the following?

a)

Reactants only

b)

Products only

c)

Reactants or products

20.

4 factors that affects reaction rate.

a)

temperature

b)

surface area

c)

presence of catalyst

d)

Chemical nature of reactant

e)

In solid form

21.

Grinding a seltzer tablet into powder increases the rate of reaction due to...

a)

increased concentration of reactants

b)

increased surface area

c)

increased speed of particles.

d)

better orientation of reactants

22.

An addition of a catalyst to the following reaction would have what effect?

a)

A would be increased

b)

B would be increased

c)

C would be decreased

d)

No change

23.

product

a)

condition of continuous, random movement of particles but no overall change in concentration of materials

b)

a measurement of how much solute exists within a certain volume of solvent or solution

c)

a substance that forms in a chemical reaction

d)

the reaction that forms products from reactants

24.

reactant

a)

the reaction that forms products from reactants

b)

a measurement of how much solute exists within a certain volume of solvent or solution

c)

a substance that takes part in and undergoes change in a chemical reaction

d)

condition of continuous, random movement of particles but no overall change in concentration of materials

25.

static equilibrium

a)

condition of continuous, random movement of particles but no overall change in concentration of materials

b)

the reaction that forms reactants from products

c)

a condition where the reaction occurring in a system is completely halted and there exists no movement between the reactants and the products corresponding to the chemical reaction

d)

a measurement of how much solute exists within a certain volume of solvent or solution

26.

dynamic equilibrium

a)

condition of continuous, random movement of particles but no overall change in concentration of materials

b)

the process by which one or more substances change to produce one or more different substances

c)

a condition where the reaction occurring in a system is completely halted and there exists no movement between the reactants and the products corresponding to the chemical reaction

d)

a substance that takes part in and undergoes change in a chemical reaction

27.

forward reaction

a)

the substance that does the dissolving

b)

the reaction that forms products from reactants

c)

to produce

d)

the reaction that forms reactants from products

28.

reverse reaction

a)

a substance that forms in a chemical reaction

b)

factors found in the built, natural, and social environments such as noise, temperature, humidity, and pressure

c)

a substance that takes part in and undergoes change in a chemical reaction

d)

the reaction that forms reactants from products

29.

What are the two factors to look for when determining if the reaction is at equilibrium?

a)

Forward reaction rate is faster than the reverse reaction rate and amounts of reactants are greater than the products

b)

Forward and reverse reaction rates are equal and amounts of reactants and products are constant

c)

Forward reaction rate is slower than the reverse reaction rate and amounts of reactants are greater than the products

d)

Forward reaction rate is faster than the reverse reaction rate and amounts of products are greater than the reactants

30.

This symbol indicates that a reaction is ____________

a)

reversible

b)

irreversible

31.

When the rate of the forward reaction is equal to the rate of backward reaction, the system is said to be in

a)

Chemical Equilibrium

b)

Chemical Balance

c)

Chemical Constant

d)

Chemical Reaction

32.

At what time does the reaction reach equilibrium?

a)

t₁

b)

t₂

c)

t₃

d)

t₄

33.

It is a chemical reaction where the reactants form products and the products form reactants.

a)

reversible reaction

b)

nonreversible reaction

c)

decomposition reaction

d)

standard reaction

34.

Identify the labels (a) and (b) on the graph.

a)

a is the amount (concentration) of reactants and b is the concentration of products

b)

a is the amount (concentration) of products and b is the concentration of reactants

c)

a is the volume of reactants and b is the volume of products

d)

a is the mass of reactants and b is the mass of products

35.

At what time (in seconds) is equilibrium established?

a)

0 seconds

b)

1 second

c)

5 seconds

d)

10 seconds

36.

Which of the two graphs reaches equilibrium?

a)

The left one.

b)

The right one.

c)

Both of them.

d)

Neither.

37.

Which of the following is NOT true at equilibrium?

a)

The forward and reverse reactions proceed at the same rate.

b)

The amount (concentration) of reactants and products do not change.

c)

The amount (concentration) of the reactants is equal to the concentration of the products.

d)

The forward and reverse reactions continue to occur.

38.

During equilibrium, the rates of the forward and the reverse reaction are ________

a)

equal

b)

unequal

c)

unequal for exothermic reactions

d)

unequal for endothermic reactions

39.

Around what time does the reaction reach equilibrium?

a)

25 min

b)

70 min

c)

45 min

d)

80 min

40.

During equilibrium, the amount of the products and the amount of the reactants are __________.

a)

equal

b)

constant (unchanging)

c)

constantly increasing

d)

constantly decreasing

41.

An equilibrium mixture is prepared in a container of fixed volume.

CO(g) + Cl₂(g) ⇌ COCl₂(g)

ΔH = −108 kJ mol⁻¹

The temperature of this mixture is decreased and the mixture is allowed to reach a new equilibrium.

Which is greater for the new equilibrium than for the original equilibrium?

a)

The mole fraction of carbon monoxide

b)

The partial pressure of chlorine

c)

The total pressure of the mixture

d)

The value of the equilibrium constant, K_p

42.

Which change would alter the value of the equilibrium constant (K_p) for this reaction?

2SO₂(g) + O₂(g) ⇌ 2SO₃(g)

a)

Increasing the total pressure of the system.

b)

Increasing the concentration of sulfur trioxide.

c)

Increasing the concentration of sulfur dioxide.

d)

Increasing the temperature

43.

Which statement about K_p is correct for this reaction in the gas phase?

W + X + Y₂ ⇌ WXY + Y

ΔH = −46 kJ mol⁻¹

a)

The value of K_p is independent of pressure.

b)

The value of K_p increases as pressure increases.

c)

The value of K_p increases as temperature increases.

d)

The value of K_p is independent of temperature.

44.

The reaction between carbon monoxide and hydrogen reaches a dynamic equilibrium.

CO(g) + 2H₂(g) <=> CH₃OH(g)

Which of these statements about a dynamic equilibrium is not true?

a)

The forward rate of reaction is equal to the backward rate of reaction.

b)

The forward rate of reaction is equal to the backward rate of reaction.

c)

The concentrations of the products and reactants are equal.

d)

The concentrations of the products and reactants are equal.

45.

Carbon monoxide and chlorine react together and reach equilibrium:

CO(g) + Cl₂(g) <=> COCl₂(g)

If the pressure of the system is then increased at constant temperature, which of the following statements is correct?

a)

The equilibrium moves to the left and K_p decreases.

b)

The equilibrium moves to the right and K_p increases.

c)

The equilibrium moves to the right, then back to the left and K_p remains the same.

d)

The equilibrium moves to the right and K_p remains the same.

46.

Hydrogen can be produced by this reaction.

CO(g) + H₂O(g) ⇌ CO₂(g) + H₂(g)

In an experiment 4.20 mol of carbon monoxide were mixed with 2.00 mol of steam. When the reaction reached equilibrium, 1.60 mol of hydrogen had been formed. (If you are not given a volume, assume it is 1dm³)

What is the value of the equilibrium constant, K_c, for this reaction?

a)

0.30

b)

0.41

c)

1.54

d)

2.46

47.

Hydrogen is produced by the reaction of methane with steam. The reaction mixture reaches a state of dynamic equilibrium.

CH₄(g) + H₂O(g) ⇌ CO(g) + 3H₂(g) ∆H = +206 kJ mol⁻¹

Which of the following shows how the equilibrium yield of hydrogen and the value of the equilibrium constant are affected by the changes shown?

a)

Change: Increase pressure

Effect on equilibrium yield of H₂(g): decrease

Effect on value of K_c: decrease

b)

Change: Add a catalyst

Effect on equilibrium yield of H₂(g): increase

Effect on value of K_c: no effect

c)

Change: Increase temperature

Effect on equilibrium yield of H₂(g): increase

Effect on value of K_c: increase

d)

Change: Remove CO(g) as formed

Effect on equilibrium yield of H₂(g): increase

Effect on value of K_c: increase

48.

Which is the correct exam technique when explaining equilibrium shifts in terms of Kc when more molecules of X is added to this system.

X <--> Y ΔH = -250kJmol -1

a)

b)

c)

49.

Which is the correct exam technique when explaining equilibrium shifts in terms of Kc when the pressure in the system is decreased?

X(g) + Y(g) <--> Z(g)

a)

b)

c)

d)

50.

Look at the equilibrium involving hydrogen, iodine and hydrogen iodide:
H2 (g) + I2(g) $\Longleftrightarrow$ 2HI (g) ∆H = -10.4 kJmol-1

What will happen to the value of Kp if the temperature is increased?

a)

Kp will stay the same

b)

Kp will increase

c)

Kp will decrease

51.

Which factors affect the rate of a reaction?

a)

polarity

b)

temperature

c)

presence of a catalyst

d)

concentration

e)

physical state

52.

When the species in a reaction have a coefficient, how do you adjust the reaction rate equation?

a)

multiply the rate by the coefficient

b)

add the coefficient to the rate

c)

divide the rate by the coefficient

d)

subtract the coefficient to the rate

53.

For the reaction $A\rightarrow B$ the reaction rate is

a)

$-\frac{\Delta\left[A\right]}{\Delta t}$

b)

$\frac{\Delta t}{\Delta\left[A\right]}$

c)

$\frac{\Delta\left[B\right]}{\Delta t}$

d)

$\frac{\Delta t}{\Delta\left[B\right]}$

54.

$k\left[A\right]^x\left[B\right]^y...$ is called the

a)

rate equation

b)

rate law equation

c)

rate constant

d)

kinetic equation

55.

What is the reaction order?

a)

the order in which the reactants change to products

b)

the speed of the reaction

c)

the relationship between the concentrations of species and the rate of a reaction

d)

the number of moles of a species in a reaction

56.

If the rate doubles when $\left[A\right]$ doubles, the rate depends on __ and the reaction is __

a)

$\left[A\right]^1$ , second order

b)

$\left[A\right]^1$ , zero order

c)

$\left[A\right]^2$ , second order

d)

$\left[A\right]^1$ , first order

57.

If the rate quadruples when [A] doubles, the rate depends on __ and the reaction is __

a)

$\left[A\right]^1$ , second order

b)

$\left[A\right]^{0\ }$ , zero-order

c)

$\left[A\right]^2$ , second order

d)

$\left[A\right]^1$ , first order

58.

If the rate does not change when [A] doubles, the rate depends on __ and the reaction is __

a)

$\left[A\right]^1$ , second order

b)

$\left[A\right]^{0\ }$ , zero-order

c)

$\left[A\right]^2$ , second order

d)

$\left[A\right]^1$ , first order

59.

The integrated rate law for a first order reaction is

a)

$\ln[A]_t=-kt+\ln[A]_0$

b)

$-\frac{1}{[A]_t}=kt+\frac{1}{[A]_0}$

c)

$\frac{1}{[A]_t}=kt+\frac{1}{[A]_0}$

d)

$\left[A\right]t=-kt+[A]_0$

60.

The integrated rate law for a second order reaction is

a)

$\ln[A]_t=-kt+\ln[A]_0$

b)

$-\frac{1}{[A]_t}=kt+\frac{1}{[A]_0}$

c)

$\frac{1}{[A]_t}=kt+\frac{1}{[A]_0}$

d)

$\left[A\right]t=-kt+[A]_0$

61.

The integrated rate law for a zero order reaction is

a)

$\ln[A]_t=-kt+\ln[A]_0$

b)

$-\frac{1}{[A]_t}=kt+\frac{1}{[A]_0}$

c)

$\frac{1}{[A]_t}=kt+\frac{1}{[A]_0}$

d)

$\left[A\right]t=-kt+[A]_0$

62.

In the rate law equation, k represents the ____________.

a)

kelvin

b)

kinetic constant

c)

rate constant

d)

reaction order

63.

The units for k in a first-order reaction are

a)

$\frac{mol}{L\cdot s}$

b)

$mol\ L^{-1}\cdot s^{-1}$

c)

$s^{-1}$

d)

$\frac{L}{mol\cdot s}$

e)

$\frac{1}{s}$

64.

The units for k in a zero-order reaction are

a)

$\frac{mol}{L\cdot s}$

b)

$mol\ L^{-1}\cdot s^{-1}$

c)

$s^{-1}$

d)

$\frac{L}{mol\cdot s}$

e)

$\frac{1}{s}$

65.

The units for k in a second-order reaction are

a)

$L\ mol^{-1}s^{-1}$

b)

$mol\ L^{-1}\cdot s^{-1}$

c)

$s^{-1}$

d)

$\frac{L}{mol\cdot s}$

e)

$\frac{1}{s}$

66.

The units for k in a third-order reaction are

a)

$L^2\ mol^{-2}s^{-1}$

b)

$mol\ L^{-1}\cdot s^{-1}$

c)

$s^{-1}$

d)

$\frac{L^2}{mol^2\cdot s}$

e)

$\frac{1}{s}$

67.

What is reaction half-life?

a)

the time required for a product concentration to reach one half of its initial value

b)

the time required for a reactant concentration to reach one half of its initial value

c)

the minimum amount of energy molucule must have for a reaction to take place

d)

the amount of reactant left when half of the allotted time for a reaction to take place has passed

68.

What is the Arrhenius Equation?

a)

$k=Ae^{\frac{E_a}{RT}}$

b)

$k=Ae^{-\frac{E_a}{RT}}$

c)

$k=-\frac{E_a}{RT}$

d)

$k=\left(\frac{E_a}{RT}\right)^{Ae}$

69.

Grinding a seltzer tablet into powder increases the rate of reaction due to increased

a)

concentration

b)

surface area

c)

temperature

d)

reactants

70.

Increasing the concentration increases the speed of reaction by

a)

lowering activation energy

b)

increasing collisions

c)

speeding up the reactants

d)

exposing more reactant

71.

Which of the following slows down the rate of a chemical reaction?

a)

Place the reactants in hot water

b)

Place the products in ice bath

c)

Place the reactants in a ice bath

d)

Keep stirring the reactants with a stirring rod

72.

The following graph shows two different reaction pathways for the same overall reaction at the same temperature. Which pathway is slower and why?

a)

Red, because the activation energy is larger

b)

Blue, because the activation energy is lower

c)

both reaction progress at the same rate

73.

Why does a higher concentration increase the rate of reaction?

a)

it increases the amount of reactants

b)

it lowers the activation energy

c)

it increases the energy of particle collisions

d)

it increases the frequency of particle collisions

74.

Why does a higher temperature increase the rate of a reaction?

a)

it increases both the frequency and energy of particle collisions

b)

it only increases the frequency of particle collisions

c)

it only increases the energy of particle collisions

d)

it reduces the activation energy of the reaction

75.

What makes an effective collision?

a)

When molecules collide.

b)

When molecules collide with the proper orientation.

c)

When molecules collide with proper orientation and enough kinetic energy.

d)

High Temperature.

76.

The minimum amount of energy needed for colliding particles to react is called

a)

Chemical Energy

b)

Kinetic Energy

c)

Activation Energy

d)

Potential Energy

77.

What type of reaction is this?

a)

Endothermic

b)

Exothermic

78.

What letter represents the activation energy?

a)

A

b)

B

c)

C

d)

D

79.

Is this reaction endothermic or exothermic?

a)

endothermic

b)

exothermic

80.

What letter represents ΔH?

a)

A

b)

B

c)

C

d)

D

81.

What is the change of the heat of the reaction (ΔH)?

a)

-40 kJ

b)

-20 kJ

c)

100 kJ

d)

60 kJ

82.

What is the activation energy?

a)

100 kJ

b)

175 kJ

c)

50 kJ

d)

75 kJ

83.

This symbol indicates that a reaction is ____________

a)

reversible

b)

irreversible

84.

What are the two factors to look for when determining if the reaction is at equilibrium?

a)

Forward reaction rate is faster than the reverse and concentrations are equal

b)

Forward and reverse reaction rates are equal and concentration is constant

c)

Forward and revers reaction rates are equal and concentration is equal

d)

Forward reaction rate is faster than the reverse and concentration is equal

85.

Identify the incorrect statement about achieving equilibrium.

a)

achieved when product and reactant concentrations are equal

b)

achieved when forward and reverse reaction rates are same

c)

achieved when concentration of reactants is stable/constant

d)

achieved when concentration ratio of reactants to products becomes stable, thus fixing the equilibrium constant (equilibrium position)

86.

At what time the reaction reached equilibrium?

a)

t₁

b)

t₂

c)

t₃

d)

t₄

87.

How do catalysts increase the rate of reaction?

a)

The frequency of collisions is the increased

b)

the activation energy is lowered

c)

the energy of collisions is increased

d)

Both the frequency and energy of collisions is increased

88.

Which of the following are true? Assume this reaction: A is reactant concentration and B is product concentration.

a)

At t3, there are more reactants than products

b)

The equilibrium constant lies to the right

c)

At t3; the amount of reactants and products are equal

d)

At t2; the forward and reverse reaction rates are equal

e)

at t1, the the concentration of the reactants is decreasing and the concentration of the products is increasing

89.

What is the keq for this reaction?

a)

Greater than 1

b)

Less than 1

c)

Exactly 1

d)

Impossible to determine

Exam II Practice Chemical Kinetics and Equilibrium

Total questions: 89

Worksheet time: 2hrs 9mins

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