Chemistry 112 Name Exam II Form A Section October...
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Chemistry 112 Name _______________________ Exam II Form A Section _______________________ October 14, 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.
Transcript of Chemistry 112 Name Exam II Form A Section October...
Chemistry 112 Name _______________________
Exam II Form A Section _______________________
October 14, 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 2 Form A
October 14, 2014 --------------------------------------------------------------------------------------------------------------------- 1) The hard-working graduate students who synthesized Nittnium are back at work! While running experiments, they synthesize Nittnium Oxide, NtO. When dissolved in water, NtO forms a basic solution. Nittnium is a: A) Metal B) Non-metal C) Metalloid D) Noble Gas E) Halogen --------------------------------------------------------------------------------------------------------------------- 2) What is the pOH of a 0.15 M solution of hypochlorous acid, HClO at 25°C? (Ka of HClO is 3.5 x 10−8) A) 4.14 B) 7.00 C) 5.44 D) 10.15 E) 9.86 --------------------------------------------------------------------------------------------------------------------- 3) Which of the following is NOT a strong acid? A) HCl
B) HClO3
C) H2SO4
D) H3PO4
E) HClO4
---------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------- 4) A solution of 1.0 M NH3 is titrated with 1.0 M HCl. Which indicator would be best suited to monitor this titration?
Indicator pH interval for color change
A. methyl red 4.2 - 6.2
B. thymol blue 8.0 - 9.6
C. methyl violet 1.0 - 2.0
D. phenolphthalein 8.5 - 10.0
E. alizarin yellow G 10.1 - 12.0
--------------------------------------------------------------------------------------------------------------------- 5) Which of the following species exhibits the greatest absolute entropy at 0°C? A) Ar (g) B) BH3 (g) C) Rn (g) D) Ca (s) E) He (g) --------------------------------------------------------------------------------------------------------------------- 6) Which of the following is most likely to act as a Lewis base?
---------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------- 7) Which one of the following salts, when dissolved in water, forms a basic aqueous solution? A) NH4Cl
B) NaBr
C) KClO3
D) FeBr3
E) NaF
--------------------------------------------------------------------------------------------------------------------- 8) A scientist prepares a solution by adding 300 mL of 0.03 M HCl to 500 mL of 0.02 M HClO4. What is the pH of the resultant solution at 25°C? A) 1.30 B) 1.00 C) 2.31 D) 0.05 E) 1.62 --------------------------------------------------------------------------------------------------------------------- 9) What is the pH of a 500 mL solution of 0.10 M NH3 at 25°C? (Kb of NH3 = 1.8 x 10−5) A) 11.3 B) 8.3 C) 13.0 D) 11.1 E) 2.7 --------------------------------------------------------------------------------------------------------------------- 10) What is the conjugate acid of HPO4
2− ? A) PO4
3− B) PO4
2− C) H2PO4
2− D) H2PO4
− E) H3PO4 ---------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------- 11) What is the concentration of HAsO4
2− in a 0.25M solution of arsenic acid (H3AsO4) if the pH of the solution is 1.46 at 25°C? For arsenic acid, Ka1 = 5.6 x 10−3, Ka2 = 1.0 x 10−7, Ka3 = 3.0 x 10−12 A) 5.6 x 10−3 M B) 1.0 x 10−7 M C) 3.0 x 10−12 M D) 6.0 x 10−1 M E) 7.1 x 10−5 M --------------------------------------------------------------------------------------------------------------------- 12) What is the pH of a 0.05 M solution of NaOCl at 25°C? (Ka of HOCl = 3.5 x 10−8) A) 4.38 B) 9.62 C) 3.92 D) 10.08 E) 11.37 --------------------------------------------------------------------------------------------------------------------- 13) Which ion below will produce the most basic solution when dissolved in water?
--------------------------------------------------------------------------------------------------------------------- 14) Calculate the percent ionization in a 0.56 M aqueous solution of phenol (C6H5OH), if the pH is 5.07 at 25°C ( Ka = 1.3 x 10−10). A) 1.5 x 10−3 % B) 1.1 x 10−1 % C) 1.5 x 10−5 % D) 2.5 % E) 3.5 x 10−3 % ---------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------- 15) Which chemical equation represents a negative change in entropy? A) C6H12O6 (s) + 6 O2 (g) → 6 CO2 (g) + 6 H2O (g)
B) NH4Cl (s) → NH4+ (aq) + Cl− (aq)
C) H2O () → H2O (g)
D) CH3NH2 (aq) + H+ (aq) → CH3NH3+ (aq)
E) 2 C4H10 () + 13 O2 (g) → 8 CO2 (g) + 10 H2O (g)
--------------------------------------------------------------------------------------------------------------------- 16) How is the chemical species NH4
+ (aq) best described? A) Weak acid B) Strong acid C) Amphoteric D) Weak base E) Spectator --------------------------------------------------------------------------------------------------------------------- 17) What would happen if 0.5 moles of NaClO2 (aq) were added to a 1 L solution of 0.5 M HClO2? I. [H+] would increase II. pH would increase III. [HClO2] would increase
IV. [OH − ] would increase A) II only B) I and II only C) II and IV only D) II, III, and IV only E) All of the above ---------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------- 18) What is the hydronium ion concentration of water at 75°C if pKw = 12.70? A) 1.0 x 10−7 M B) 4.5 x 10−7 M C) 2.0 x 10−13 M D) 1.0 x 10−14 M E) 3.5 x 10−5 M --------------------------------------------------------------------------------------------------------------------- 19) To prepare a solution for an important series of reactions, a chemist adds 500 mL of 1 M NaOH to 1000 mL of 1 M CH3COOH (Ka = 1.8 x 10−5). What is the pH of the resultant solution at 25°C? A) 1.80 B) 4.74 C) 5.12 D) 6.80 E) 7.89 --------------------------------------------------------------------------------------------------------------------- 20) A 34-year-old man presents at an emergency room with fatigue, nausea, headache, and low blood pressure. Upon further examination, it is found that his blood concentration of H2CO3 is 2.4 mmol/L, and the concentration of HCO3
− in his blood is 22 mmol/L. What is the pH of his blood? (Ka1 of H2CO3 = 4.3 x 10−7) A) 6.37 B) 5.41 C) 7.33 D) 7.41 E) 7.12 ---------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------- PLEASE USE THE FOLLOWING INFORMATION TO ANSWER THE NEXT 2 QUESTIONS: A researcher performs a titration to determine the buffering capacity of a mixture of two solutions. The researcher starts with 1 L of Solution A and performs a titration by adding Solution B and recording the pH. The data are collected and plotted on a graph:
------------------------------------------------------- 21) Which of the following best describes the identities of Solution A and Solution B? Solution A Solution B A) Weak base Strong base B) Strong acid Weak base C) Strong acid Strong base D) Weak acid Strong acid E) Weak acid Strong base
------------------------------------------------------- 22) Approximately what volume of Solution B must be added to reach the half equivalence point of the titration? A) 250 mL B) 450 mL C) 800 mL D) 900 mL E) 1100 mL ---------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------- 23) What is the pH of a 0.050 M solution of Ca(OH)2 at 25°C? A) 1.0 B) 1.3 C) 12.7 D) 13.0 E) 13.5 --------------------------------------------------------------------------------------------------------------------- 24) Calculate the Ka of a weak acid HA if a 0.19 M solution of HA has a pH of 4.52 at 25°C. A) 6.5 x 10−9 B) 4.9 x 10−9 C) 1.8 x 10−5 D) 3.2 x 10−3 E) 2.1 x 10−8 --------------------------------------------------------------------------------------------------------------------- 25) A titration enthusiast decides to titrate a 200 mL solution of 0.45 M benzoic acid (C6H5COOH) with 0.90 M NaOH. (Ka of benzoic acid is 6.5 x 10−5) What is the pH of the titrated solution at its equivalence point at 25°C? A) 8.92 B) 7.00 C) 4.14 D) 8.83 E) 5.17 --------------------------------------------------------------------------------------------------------------------- --------------------------------------------------------------------------------------------------------------------- ---------------------------------------------------------------------------------------------------------------------
END OF TEST
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]
