Chemistry 112 Name _______________________

Exam I Form A Section _______________________

September 16, 2014 eMail _______________________

IMPORTANT: On the scantron (answer sheet), you MUST clearly fill your name, your student number, section number, and test form (white cover = test form A; yellow cover = test form B). Use a #2 pencil.

There are 25 questions on this exam. Check that you have done all of the problems and filled in the first 25 bubbles on the scantron. The maximum score on this exam is 25 points. Your score will be reported in percent (max 100%).

Exam policy

• Calculators with text-programmable memory are not allowed. • Relevant data and formulas, including the periodic table, are attached at the end of this

exam. • Your grade will be based only on what is on the scantron form. • The answer key will be posted on the web after the exam (on the Exam Schedule page). • You must turn in your cover sheet with your scantron answer form.

Hints

• As you read the question, underline or circle key words to highlight them for yourself. Avoid errors from "mis-reading" the question.

• Pay attention to units and magnitudes (decimal places) of numbers obtained from calculations.

• There is no penalty for guessing.

CHEMISTRY 112 EXAM 1 Form A

Sept. 16, 2014

1. Which of the following correctly describes the above reaction? A) Exothermic with 2 activated complexes and 3 intermediates B) Endothermic with 2 activated complexes and 3 transition states C) Endothermic with 3 transition states and 2 intermediates D) Endothermic with 2 reactants and 3 products E) Exothermic with 2 activated complexes and 3 intermediates 2. What is the missing product in this fission reaction?

235U + 1n → 3 1n + 90Sr + ___ A) 142I B) 143I C) 146I D) 142Xe E) 143Xe 3. Which of the following is true? A) Beta decay results in the conversion of a proton into a neutron. B) Positron emission increases the nuclear charge of an atom. C) Nuclear decay always follows second-order kinetics. D) Gamma decay produces high-energy radiation. E) Alpha decay decreases the atomic number of the parent atom by 1. ---------------------------------------------------------------------------------------------------------------------

--------------------------------------------------------------------------------------------------------------------PLEASE USE THE FOLLOWING KINETIC DATA TO ANSWER THE FOLLOWING 2 QUESTIONS ABOUT THIS REACTION: A + B + C → P + R

Experiment [A] (M) [B] (M) [C] (M) Reaction Rate (M/s)

1 0.40 0.40 0.40 2.0 x 10−4 2 0.80 0.40 0.40 4.0 x 10−4 3 0.40 0.80 0.40 2.0 x 10−4 4 0.40 0.80 0.80 8.0 x 10−4

-------------------------------------------------------------

4. What is the rate law for this reaction? A) Rate = k[A][B][C]2

B) Rate = k[A]2[B][C]2

C) Rate = k[A][C]2 D) Rate = k[A]1/2[B][C]2 E) Rate = k[A]2[C]3

------------------------------------------------------------- 5. What is the value of the rate constant, k and its units? A) 3.13 x 10−3 M−2s−1 B) 1.25 x 10−3 M−2s−1 C) 2.00 x 10−4 M−1s−1 D) 3.13 x 10−3 M−1s−1 E) 6.40 x 10−2 M−1s−1 6. Acetaminophen is eliminated from cerebrospinal fluid of the body with a first order half-life of 3.2 hours. If the concentration of acetaminophen in an ailing student is 15 µL/mL at 1:00 pm, what will be the concentration at 8:00 pm? A) 3.29 µL/mL B) 13.00 µL/mL C) 4.37 µL/mL D) 0.22 µL/mL E) The drug will be completely cleared from the cerebrospinal fluid. ---------------------------------------------------------------------------------------------------------------------

--------------------------------------------------------------------------------------------------------------------- 7. Which of the following isotopes is most likely to undergo fusion? A) Helium-4 B) Iron-56 C) Uranium-235 D) Uranium-238 E) Mendelevium-256 8. Ethanol decomposes on an alumina surface with a second-order rate constant of 4.00 x 10-5 M−1s−1 at 600 K. If the initial concentration of ethanol is 0.5 M, what is the concentration after 8 hours? A) 0.13 M B) 0.17 M C) 0.23 M D) 0.27 M E) 0.32 M 9. The decomposition of Compound A was studied and the following data were collected. The slope of the line is −0.073 s−1 and the y-intercept is 0.40. What is the half-life of Compound A? A) 0.07 s B) 0.40 s C) 9.50 s D) 13.70 s E) 34.20 s 10. Which of the following isotopes are most likely to undergo beta decay? A) 1H B) 12N C) 14C D) 19Ne E) 235U

--------------------------------------------------------------------------------------------------------------------- PLEASE USE THE FOLLOWING 3-STEP MECHANISM TO ANSWER THE FOLLOWING 2 QUESTIONS:

NO (g) + NO (g) → N2O2 (g) (fast) N2O2 (g) + H2 (g) → N2O (g) + H2O (g) (slow)

N2O (g) + H2 (g) → N2 (g) + H2O (g) (fast)

------------------------------------------------------------- 11. What is the rate law for the overall reaction? A) Rate = kobs[NO]2 B) Rate = kobs[N2O2][H2] C) Rate = kobs[N2O][H2] D) Rate = kobs[NO]2[H2] E) Rate = kobs[NO][N2O2][H2]

------------------------------------------------------------- 12. What is the role of N2O in this reaction mechanism? A) reactant B) product C) catalyst D) activated complex E) intermediate 13. Which of the following statements are true about catalysts?

i. A catalyst increases the value of the equilibrium constant, Keq. ii. A catalyst lowers the activation energy of the reaction, Ea. iii. A catalyst lowers the energy of the products and stabilizes them.

A) i only B) ii only C) iii only D) ii and iii only E) All of the above 14. What is the final product when Uranium-238 undergoes 5 alpha decay reactions and 2 beta decay reactions? A) radon-226 B) lead-218 C) polonium-218 D) plutonium-244 E) radium-226

--------------------------------------------------------------------------------------------------------------------- 15. Chlorofluorocarbons are known to have a damaging effect on the ozone layer because chlorotrifluoromethane (CF3Cl), once commonly used as a refrigerant, can split into the free radicals CF3 and Cl in the atmosphere. The radical Cl then reacts as follows:

Cl + O3 → ClO + O2 ClO + O → Cl + O2

What is the concern with the free radical Cl with respect to the ozone layer? A) It acts as a reactant, consuming ozone (O3). B) It acts as a catalyst, consuming ozone (O3). C) It creates a very high-energy transition state. D) It creates ClO, a potent catalyst. E) It is a product in the overall reaction, creating a poisonous free radical in the lower stratosphere. 16. Glucose (C6H12O6) is combusted according to the following equation:

C6H12O6 (s) + 6 O2 (g) → 6 CO2 (g) + 6 H2O (g)

When glucose is being consumed at a rate of 0.12 moles per second, what is the rate of production of carbon dioxide? A) 0.02 mol/s B) 0.12 mol/s C) 0.24 mol/s D) 0.60 mol/s E) 0.72 mol/s 17. A present-day rock is found to contain 2.70 g of 238U and 1.72 g of 206Pb. What is the age of the rock? (The half-life of the decay of 238U to 206Pb is 4.51 x 109 years.) A) 3.21 x 109 y B) 3.59 x 109 y C) 4.11 x 109 y D) 4.56 x 109 y E) 4.99 x 109 y

--------------------------------------------------------------------------------------------------------------------- 18. A 100 mL flask is filled with 0.124 moles of A and allowed to react to form product B according to the following reaction:

2 A(g) → B(g) The data in the table are obtained for [A]t as the reaction proceeds. How many moles of B are present at 40 seconds? Time (s) 0.0 10.0 20.0 30.0 40.0 Moles of A 0.124 0.110 0.088 0.073 0.054 A) 0.070 moles B) 0.035 moles C) 0.140 moles D) 0.054 moles E) 0.027 moles 19. A group of ambitious Penn State graduate students synthesize a new element and decide to call it Nittnium. Further experimentation determines the half-life of Nittnium to be 1,855 s. The students create a batch of Nittnium to run experiments on, but then they let it sit for one hour while they run to West Halls to grab some cookies. What fraction of Nittnium will remain when they get back to their lab? A) 3% B) 14% C) 26% D) 34% E) 48% 20. Graduate students at a different university synthesize their own new element and decide to call it Pittonium. Immediately upon synthesis of the sample, the students observe an activity of 160 disintegrations per second. After 16 minutes, the students observe an activity of only 10 disintegrations per second. What is the half-life of Pittonium? A) 1.6 minutes B) 4.0 minutes C) 3.2 minutes D) 8.0 minutes E) 4.8 minutes

21. What is the nuclear binding energy of 1 mole of Lithium-7 nuclei? (The atomic mass of one Lithium-7 nucleus is 7.016003 amu.) A) 7.023 x 103 KJ B) 9.126 x 105 KJ C) 5.226 x 106 KJ D) 3.644 x 109 KJ E) 7.424 x 1017 KJ 22. The progress of the reaction A → B is shown below where the dark spheres represent A molecules and the light spheres represent B molecules. What is the rate constant in this reaction? t = 0 s t = 20 s t = 40 s A) 0.075 s−1 B) 0.120 s−1 C) 1.330 s−1 D) 0.017 s−1 E) 0.035 s−1 23. If a reaction is twice as fast at 123°C than it is at 23°C, then what is its activation energy? A) 100 J/mol B) 163 J/mol C) 6.9 KJ/mol D) 24.2 KJ/mol E) 100 KJ/mol ---------------------------------------------------------------------------------------------------------------------

--------------------------------------------------------------------------------------------------------------------- 24. Which of the following statements are true regarding endothermic reactions?

i. The reverse reaction will have a lower Ea than the forward reaction. ii. An endothermic reaction requires a catalyst to proceed in the forward direction. iii. An endothermic reaction releases energy.

A) i only B) ii only C) iii only D) i and ii only E) All of the above are true 25. Substances A and B react with each other such that A is 75% consumed in 16 minutes and A is 87.5% consumed in 24 minutes. Changing the concentration of B has no effect on the reaction rate. The reaction is: A) Zero order in both A and B B) First order in both A and B C) Second order in A and zero order in B D) First order in A and zero order in B E) There is insufficient information to answer this question --------------------------------------------------------------------------------------------------------------------- --------------------------------------------------------------------------------------------------------------------- ---------------------------------------------------------------------------------------------------------------------

END OF EXAM

CHEM 112 Fa14 Exam 1 - Form A

Scrap Paper

Chem 112 Equations Constants, Conversions And Equations For Use During Exams And Quizzes

 

Conversions    Constants 

1J kg m2 s2 C V     c 2.99792458 108 m s1    R 0.08206 L atm mol1 K1 

1A C s1    h 6.63 1034 J s     R 8.314 J mol1 K1 

1g 6.021023 amu    F 96,485 C mol1    01 n 1.0086649 amu  

    NA 6.0221023 mol1     1

1 p 1.0072765 amu  

    KW 11014 at 25 oC      

Equations 

k Ae

Ea

RT

 Rate kN   G H TS nFE  

ln k E

a

RT ln A   ln

Nt

N0

0.693t

t1 2

kt   Go 2.303 RT log K RT ln K  

ln A ln A 0 kt   E= h hc

  G Go RT ln Q  

lnk

1

k2

E

a

R

1T

2

1T

1

  E = mc2   G Go 2.303 RT log Q  

t1 2

ln2k

0.693

k  K

aK

b K

W H OH   Eo

0.0592n

log K at 25 oC  

1A

1

A 0

kt   pH pKa log

X HX

  E Eo 0.0592

nlog Q at 25 oC  

Kp

= Kc

RT n pKW pHpOH pK

a pK

b  

Molecular Orbital Theory Diagrams  Crystal Field Theory Diagram                                        Color Wheel with Wavelength Ranges                                                         

   

Chem 112 Equations Constants, Conversions And Equations For Use During Exams And Quizzes

Standard Reduction Potentials in Water at 25°C   Half Reaction  E°1/2(V) 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

PERIODIC TABLE of the ELEMENTS MAIN GROUPS MAIN GROUPS

1A 1

8A 18

1 H

1.008

2A 2

3A 13

4A 14

5A 15

6A 16

7A 17

2 He

4.003

3 Li

6.941

4 Be

9.012

TRANSITION METALS

5 B

10.811

6 C

12.011

7 N

14.007

8 O

15.999

9 F

18.998

10 Ne

20.180

11 Na

22.990

12 Mg

24.305

3B 3

4B 4

5B 5

6B 6

7B 7

8B 8

8B 9

8B 10

1B 11

2B 12

13 Al

26.982

14 Si

28.086

15 P

30.974

16 S

32.066

17 Cl

35.453

18 Ar

39.948

19 K

39.098

20 Ca

40.078

21 Sc

44.956

22 Ti

47.867

23 V

50.942

24 Cr

51.996

25 Mn

54.938

26 Fe

55.845

27 Co

58.933

28 Ni

58.693

29 Cu

63.546

30 Zn

65.39

31 Ga

69.723

32 Ge 72.61

33 As

74.992

34 Se

78.96

35 Br

79.904

36 Kr

83.80

37 Rb

85.468

38 Sr

87.62

39 Y

88.906

40 Zr

91.224

41 Nb

92.906

42 Mo 95.94

43 Tc [98]

44 Ru

101.07

45 Rh

102.90

46 Pd

106.42

47 Ag

107.87

48 Cd

112.41

49 In

114.82

50 Sn

118.71

51 Sb

121.76

52 Te

127.60

53 I

126.90

54 Xe

131.29

55 Cs

132.91

56 Ba

137.33

57 La*

138.91

72 Hf

178.49

73 Ta

180.95

74 W

183.84

75 Re

186.21

76 Os

190.23

77 Ir

192.22

78 Pt

195.08

79 Au

196.97

80 Hg

200.59

81 Tl

204.38

82 Pb

207.2

83 Bi

208.98

84 Po [209]

85 At

[210]

86 Rn [222]

87 Fr

[223]

88 Ra [226]

89 Ac** [227]

104 Rf

[261]

105 Db [262]

106 Sg [266]

107 Bh [264]

108 Hs [265]

109 Mt [268]

110

[269]

111

[272]

112

[277]

114

[285]

116

[289]

118

[293]

* LANTHANOIDS 58 Ce

140.12

59 Pr

140.91

60 Nd

144.24

61 Pm [145]

62 Sm

150.36

63 Eu

151.96

64 Gd

157.25

65 Tb

158.92

66 Dy

162.50

67 Ho

164.93

68 Er

167.26

69 Tm

168.93

70 Yb

173.04

71 Lu

174.97

** ACTINOIDS

90 Th

232.04

91 Pa

231.04

92 U

238.03

93 Np [237]

94 Pu [244]

95 Am [243]

96 Cm [247]

97 Bk [247]

98 Cf

[251]

99 Es [252]

100 Fm [257]

101 Md [258]

102 No [259]

103 Lr

[262]