Kinetics Practice Test Multiple Choice


PART II Write the correct term (or terms) in the space provided



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PART II Write the correct term (or terms) in the space provided.
____ 55. The energy change, E, for a reaction is the energy difference between the

a.

products and intermediates.

b.

products and reactants.

c.

products and the activated complex.

d.

reactants and intermediates.



Short Answer
1. What factors determine whether a molecule collision produces a reaction?
2. What is an activated complex?
3. List all of the factors that influence the rate of a chemical reaction.
4. What is the relationship between pressure and the rate of a chemical reaction?
5. What is catalysis?
6. How do you find a reaction order?
PART IV Write the answers to the following questions in the space provided.
7. What is the difference between homogeneous reactions and heterogeneous reactions?
8. How does the energy of the activated complex compare with the energies of reactants and products?
9. List the five factors that can influence reaction rate.
10. Explain why the energy and orientation of the collision of atoms and molecules is important in chemical reactions.
11. Identify the step used to determine the rate law if a chemical reaction proceeds in a sequence of steps.
PART V Complete the problems in the space provided.
12. Draw an energy profile for an exothermic reaction. Label reactants, products, activated complex, and activation energy.
13. Draw an energy profile of a reaction with and without a catalyst. Compare the two reactants with respect to the activation energy and the net energy change.
14. Write the general equation for the rate law, and identify each variable and constant.
15. Determine the rate law equation for the following reaction, given the experimental data shown below.
3AB

Trial run

[A]

Reaction rate

1

0.4 M

2.0 M/s

2

0.8 M

8.0 M/s

16. Use the following chemical equation to answer the question below.

Mg(s) + 2H3O+(aq) + Cl(aq) Mg2(aq) + 2Cl(aq) + H2(g) + H2O(l)

If 0.060 g of magnesium completely react in 25 s, what is the average reaction rate in moles/second over that time interval? (The atomic mass of Mg is 24.3 amu.) Show your work.


17. What is the order of a reaction if its rate increases by a factor of 13 when the reactant concentration increases by a factor of 3.6?
Essay
1. Explain why it is often necessary to start a campfire with many small pieces of kindling rather than with a few large logs.
2. Explain what happens to the energy as a substrate and an enzyme interact.
Problem
1. A 5.0 g piece of sodium metal is dropped into 100.0 g of water. After a period of 15 s, 14.8 mL of hydrogen gas has been collected. Write a balanced equation for this reaction and determine an average rate for the reaction in mL/s.
2. When hydrogen sulfide gas is passed through a solution of lead(II) nitrate, lead(II) sulfide precipitates out. Write a balanced chemical equation for this reaction and calculate an average rate, in mol/s, for the reaction from the data supplied below. The molar mass of lead(II) sulfide is 239.27g/mol.

Table 1 Lead(II) Sulfide Precipitation

Time (s)

Mass of lead(II) sulfide formed (g)

0.0

0.0

5.0

2.8

10.0

6.1

15.0

9.0

20.0

11.7

3. Nitrogen dioxide and fluorine react in the gas phase according to the following equation:




A proposed reaction mechanism for this reaction follows:


Identify the rate-determining step and write an acceptable rate law.
4. Three experiments that have identical conditions were performed to measure the initial rate of decomposition of ammonia on a platinum surface:. The results for the three experiments in which only the NH3 concentration was varied are as follows:


Experiment

[NH3] (M)

Rate (M/s)

1

0.040

4.5 10–2

2

0.080

9.0 10–2

3

0.120

1.35 10–1

Write the rate law for the reaction. Find the value and units of the specific rate

constant.
5. Three experiments are performed under identical conditions to measure the initial rate of the reaction described by the equation . The results of the three experiments, in which only the N2O5 concentration is varied, are as follows:


Experiment

[N2O5] (M)

Rate (M/s)

1

0.030

2.2 10–2

2

0.060

8.8 10–2

3

0.090

1.98 10–1

Write the rate law for the reaction. Find the value and units of the specific rate constant.


Completion

Complete each statement.
PART II Write the correct term (or terms) in the space provided.
1. The sequence of steps in a reaction process is called the ____________________.
2. A substance that increases the rate of a chemical reaction without being consumed is a(n) ____________________.
3. To be effective, a collision requires these two things: ____________________ and ____________________.
4. The a favorable orientation is the slowest step in a mechanism. ____________________
5. Breaking bonds ____________________ energy in the form of heat. This means that bond breaking is a(n) ____________________ process.
6. Reactions involving reactants with only one phase are ____________________ reactions.
7. The power to which a reactant concentration is raised in a rate law equation is called the ____________________ in that reactant.
8. The ____________________ is the proportionality constant relating the rate of the reaction to the concentrations of reactants.
9. The activated complex is ____________________ in energy than the reactants.
Matching
PART III The bottom column below gives ways you can change a chemical system, and the top column gives possible effects of those changes. Write the letter of the probable effect to each change in the bottom column. (Letters can be used more than once.)


a.

increases the reaction rate

b.

decreases the reaction rate

c.

might increase or decrease the reaction rate

d.

doesn’t affect the reaction rate

____ 1. increasing temperature


____ 2. decreasing surface area
____ 3. adding a catalyst
____ 4. decreasing reactant concentration
____ 5. changing concentration of a zero-order reactant
Kinetics Practice Test

Answer Section
MULTIPLE CHOICE
1. ANS: A PTS: 1 DIF: I

REF: d2e03991-f97e-11de-9c72-001185f0d2ea OBJ: 1


2. ANS: D PTS: 1 DIF: I

REF: d2e29bee-f97e-11de-9c72-001185f0d2ea OBJ: 1


3. ANS: D PTS: 1 DIF: I

REF: d2e4fe4b-f97e-11de-9c72-001185f0d2ea OBJ: 1


4. ANS: C PTS: 1 DIF: II

REF: d2e787b8-f97e-11de-9c72-001185f0d2ea OBJ: 1


5. ANS: C PTS: 1 DIF: I

REF: d2e9c305-f97e-11de-9c72-001185f0d2ea OBJ: 1


6. ANS: D PTS: 1 DIF: I

REF: d2f34c79-f97e-11de-9c72-001185f0d2ea OBJ: 2


7. ANS: C PTS: 1 DIF: I

REF: d2f37389-f97e-11de-9c72-001185f0d2ea OBJ: 2


8. ANS: B PTS: 1 DIF: I

REF: d2f81133-f97e-11de-9c72-001185f0d2ea OBJ: 2


9. ANS: C PTS: 1 DIF: I

REF: d2f83843-f97e-11de-9c72-001185f0d2ea OBJ: 2


10. ANS: D PTS: 1 DIF: I

REF: d2fa7390-f97e-11de-9c72-001185f0d2ea OBJ: 2


11. ANS: B PTS: 1 DIF: I

REF: d2fa9aa0-f97e-11de-9c72-001185f0d2ea OBJ: 2


12. ANS: C PTS: 1 DIF: I

REF: d2fcd5ed-f97e-11de-9c72-001185f0d2ea OBJ: 3


13. ANS: C PTS: 1 DIF: I

REF: d3019aa7-f97e-11de-9c72-001185f0d2ea OBJ: 3


14. ANS: C PTS: 1 DIF: I

REF: d3042414-f97e-11de-9c72-001185f0d2ea OBJ: 3


15. ANS: B PTS: 1 DIF: I

REF: d3065f61-f97e-11de-9c72-001185f0d2ea OBJ: 3


16. ANS: C PTS: 1 DIF: I

REF: d308c1be-f97e-11de-9c72-001185f0d2ea OBJ: 3


17. ANS: A PTS: 1 DIF: I

REF: d308e8ce-f97e-11de-9c72-001185f0d2ea OBJ: 4


18. ANS: A PTS: 1 DIF: I

REF: d30d8678-f97e-11de-9c72-001185f0d2ea OBJ: 4


19. ANS: A PTS: 1 DIF: I

REF: d30fe8d5-f97e-11de-9c72-001185f0d2ea OBJ: 4


20. ANS: A PTS: 1 DIF: I

REF: d3100fe5-f97e-11de-9c72-001185f0d2ea OBJ: 4


21. ANS: A PTS: 1 DIF: I

REF: d3124b32-f97e-11de-9c72-001185f0d2ea OBJ: 4


22. ANS: D PTS: 1 DIF: I

REF: d3170fec-f97e-11de-9c72-001185f0d2ea OBJ: 4


23. ANS: C PTS: 1 DIF: I

REF: d3199959-f97e-11de-9c72-001185f0d2ea OBJ: 1


24. ANS: C PTS: 1 DIF: I

REF: d31bd4a6-f97e-11de-9c72-001185f0d2ea OBJ: 1


25. ANS: B PTS: 1 DIF: I

REF: d31e3703-f97e-11de-9c72-001185f0d2ea OBJ: 1


26. ANS: B PTS: 1 DIF: I

REF: d32322cd-f97e-11de-9c72-001185f0d2ea OBJ: 1


27. ANS: A PTS: 1 DIF: I

REF: d3255e1a-f97e-11de-9c72-001185f0d2ea OBJ: 2


28. ANS: D PTS: 1 DIF: I

REF: d325852a-f97e-11de-9c72-001185f0d2ea OBJ: 2


29. ANS: A PTS: 1 DIF: I

REF: d327c077-f97e-11de-9c72-001185f0d2ea OBJ: 2


30. ANS: A PTS: 1 DIF: I

REF: d32c8531-f97e-11de-9c72-001185f0d2ea OBJ: 2


31. ANS: D PTS: 1 DIF: I

REF: d32ee78e-f97e-11de-9c72-001185f0d2ea OBJ: 2


32. ANS: B PTS: 1 DIF: I

REF: d33149eb-f97e-11de-9c72-001185f0d2ea OBJ: 2


33. ANS: A PTS: 1 DIF: I

REF: d3360ea5-f97e-11de-9c72-001185f0d2ea OBJ: 2


34. ANS: A PTS: 1 DIF: I

REF: d3387102-f97e-11de-9c72-001185f0d2ea OBJ: 2


35. ANS: B PTS: 1 DIF: I

REF: d33ad35f-f97e-11de-9c72-001185f0d2ea OBJ: 3


36. ANS: C PTS: 1 DIF: I

REF: d33f9819-f97e-11de-9c72-001185f0d2ea OBJ: 3


37. ANS: A PTS: 1 DIF: I

REF: d341fa76-f97e-11de-9c72-001185f0d2ea OBJ: 3


38. ANS: D PTS: 1 DIF: I

REF: d34483e3-f97e-11de-9c72-001185f0d2ea OBJ: 3


39. ANS: D PTS: 1 DIF: I

REF: d346bf30-f97e-11de-9c72-001185f0d2ea OBJ: 3


40. ANS: B PTS: 1 DIF: I

REF: d349489d-f97e-11de-9c72-001185f0d2ea OBJ: 4


41. ANS: D PTS: 1 DIF: I

REF: d34de647-f97e-11de-9c72-001185f0d2ea OBJ: 4


42. ANS: D PTS: 1 DIF: I

REF: d34e0d57-f97e-11de-9c72-001185f0d2ea OBJ: 4


43. ANS: A PTS: 1 DIF: I

REF: d35048a4-f97e-11de-9c72-001185f0d2ea OBJ: 4


44. ANS: C PTS: 1 DIF: I

REF: d355346e-f97e-11de-9c72-001185f0d2ea OBJ: 4


45. ANS: D PTS: 1 DIF: I

REF: d3576fbb-f97e-11de-9c72-001185f0d2ea OBJ: 4


46. ANS: C PTS: 1 DIF: I

REF: d35c3475-f97e-11de-9c72-001185f0d2ea OBJ: 5


47. ANS: C PTS: 1 DIF: I

REF: d360f92f-f97e-11de-9c72-001185f0d2ea OBJ: 5


48. ANS: C PTS: 1 DIF: I

REF: d363829c-f97e-11de-9c72-001185f0d2ea OBJ: 5


49. ANS: D PTS: 1 STA: TEKS C.11A

TOP: Chemistry Chapter 17 - Standardized Test Practice


50. ANS: D PTS: 1 STA: TEKS C.11A

TOP: Chemistry Chapter 17 - Standardized Test Practice


51. ANS: D PTS: 1 STA: TEKS C.11A

TOP: Chemistry Chapter 17 - Standardized Test Practice


52. ANS: D PTS: 1 STA: TEKS C.11A

TOP: Chemistry Chapter 17 - Standardized Test Practice


53. ANS: B PTS: 1 STA: TEKS C.11A

TOP: Chemistry Chapter 17 - Standardized Test Practice


54. ANS: C PTS: 1 STA: TEKS C.11A

TOP: Chemistry Chapter 17 - Standardized Test Practice


55. ANS: B PTS: 1 STA: TEKS C.11C

TOP: Chapter 17 Test B


SHORT ANSWER
1. ANS:

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

PTS: 1 DIF: I REF: d3682046-f97e-11de-9c72-001185f0d2ea

OBJ: 2
2. ANS:

It is a temporary union of atoms, corresponding to a maximum potential energy, formed midway between reactants and products.

PTS: 1 DIF: I REF: d36a82a3-f97e-11de-9c72-001185f0d2ea

OBJ: 3
3. 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.

PTS: 1 DIF: I REF: d36aa9b3-f97e-11de-9c72-001185f0d2ea

OBJ: 2
4. ANS:

Doubling the pressure of a gas doubles its concentration and, thus, will increase the rate of a reaction.

PTS: 1 DIF: I REF: d36ce500-f97e-11de-9c72-001185f0d2ea

OBJ: 2
5. ANS:

It is the process in which an increase in reaction rates is caused by the presence of a catalyst.

PTS: 1 DIF: I REF: d36f475d-f97e-11de-9c72-001185f0d2ea

OBJ: 3
6. ANS:

Compare the rate ratio with a concentration ratio.

PTS: 1 DIF: I REF: d36f6e6d-f97e-11de-9c72-001185f0d2ea

OBJ: 4
7. ANS:

Homogeneous reactions involve reactants and products that exist in a single phase. Heterogeneous reactions involve reactants in two different phases.

PTS: 1 TOP: Chapter 17 Test B
8. ANS:

The energy of the activated complex is greater than the energy of the reactants and greater than the energy of the products.

PTS: 1 TOP: Chapter 17 Test B
9. ANS:

nature of reactants, surface area, temperature, concentration, presence of catalysts

PTS: 1 TOP: Chapter 17 Test B
10. ANS:

In order for a reaction to occur, the molecules or atoms must collide with sufficient energy to overcome the activation energy barrier. The collision also must occur in the correct orientation, in most cases at a particular end of a molecule or atom.

PTS: 1 TOP: Chapter 17 Test B
11. ANS:

The rate law is determined from the slowest step, called the rate-determining step because it has the slowest rate.



PTS: 1 TOP: Chapter 17 Test B
12. ANS:

PTS: 1 TOP: Chapter 17 Test B


13. ANS:

The activation energy is lower with a catalyst than without the catalyst, but the net energy change is the same for both reactions.

PTS: 1 TOP: Chapter 17 Test B
14. ANS:

R= k[A]n[B]m. R is the reaction rate, k is the specific rate constant, [A] and [B] are the molar concentrations of the reactants, and n and m are the respective powers to which the concentrations are raised.

PTS: 1 TOP: Chapter 17 Test B


15. ANS:

R= k[A]2

PTS: 1 TOP: Chapter 17 Test B


16. ANS:

PTS: 1 TOP: Chapter 17 Test B


17. ANS:

two


PTS: 1 TOP: Chapter 17 Test B
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