Chemistry 2 Exam
Roane State Academic Festival
Name______________________________________(print neatly) School _________________
There are fifteen question on this exam. Each question is weighted equally. On the answer
sheet, write your name in the space provided and your answers in the blanks provided. There is
also a bonus question. It will be used as a tie breaker and will be assigned partial credit.
Therefore, for this bonus question show your work VERY NEATLY in the space provided on the
answer sheet. When you are finished bring you answer sheets to the front and exit quietly.
Please refrain from discussing the exam in the hallway since others may still be working
NOTE: If there are units associated with the answer, full credit with NOT be given without the
units.
1 mole = 6.022 × 1023 particles
760 torr / 1 atm
R = 0.08206 L atm mol-1 K-1
1. How many molecules are there in 52.0 g of NH3?
2. In the following reaction is not balanced. For the real reaction 57.0 g of UH3 are formed.
How many grams of hydrogen are needed to produce this 57.0 g of product?
U(s) + H2(g) ! UH3(s)
3. What volume of 1.00 M KOH solution would contain 52.0 g of KOH?
4. What volume of 0.1021 M NaOH is required to reach the second endpoint of 25.00 mL of a
0.1300 M H3PO4 solution? The reaction is:
2NaOH + H3PO4 ! Na2HPO4 + 2H2O
5. What is the volume of a gas, originally at 650 torr with a volume of 57.0 L, if it were
compressed and the pressure increased to 1500 torr?
6. Calculate the normality of an unknown acid if 0.456 g of NaOH is required to neutralize
20.00 mL of the acid.
7. Balance the following redox reaction:
NO2 + H2O ! HNO3 + NO
8. For the following reaction, the pressures listed below the reactants and products are the
pressures observed. Calculate the K for the reaction.
N2(g)
0.60 atm
+
3H2(g)
0.42 atm
º
2NH3
0.11 atm
9. Calculate the enthalpy of the following reaction:
2C2H5OH(l) + 7O2(g) ! 4CO2(g) + 6H2O(g)
∆fHO(C2H5OH(l)) = !277.7 kJ mol!1
∆fHO(CO2(g)) = !393.51 kJ mol!1
∆fHO(H2O(g)) = !241.8 kJ mol!1
10. For the following reaction tell what would happen if one were to 1) increase the Cl2
pressure, 2) increase the overall pressure and 3) increase the temperature.
PCl3 + Cl2 º PCl5
∆rHO = !108 kJ mol!1
11) What is the molar solubility of AgBr in pure water? The Ksp for AgBr is 5.35 × 10-13.
12) How many grams of calcium fluoride, CaF2, can dissolve in a solution that contains 0.010 M
sodium fluoride, NaF? (Ksp (CaF2) = 4.0 × 10!11)
13) What is the pH of a solution that has a total OH! concentration of 2.5 × 10-8?
14) What is the pH of a 0.10 M solution of HCOOH. (Ka (HCOOH) = 1.76 × 10!4)
15) Using the standard potential tables, determine the potential for the following reaction:
2PbSO4 + 2H2O ! Pb + PbO2 + 2H2SO4
Chemistry 2 Exam
Roane State Academic Festival
Answer Sheet
Team _______________________
Name_________________________________________
(PRINT NEATLY)
School ______________________
1. __________________________________________________________________________
2. __________________________________________________________________________
3. __________________________________________________________________________
4. __________________________________________________________________________
5. __________________________________________________________________________
6. __________________________________________________________________________
7. __________________________________________________________________________
8. __________________________________________________________________________
9. __________________________________________________________________________
10. 1) The reaction shifts to the _________________________________
2) The reaction shifts to the _________________________________
3) The reaction shifts to the _________________________________
11. __________________________________________________________________________
12. __________________________________________________________________________
13. __________________________________________________________________________
14. __________________________________________________________________________
15. __________________________________________________________________________
Bonus Question answer:_________________________________________________________
Chemistry 2 Exam
Roane State Academic Festival
Bonus Question
Name______________________________________(print neatly) School _________________
Answer the following question showing all your work NEATLY.
In a titration of acetic acid (CH3COOH) with NaOH, the pH of the solution was measured when
10.00 mL of NaOH was added to 25.00 mL of CH3COOH. The concentration of the NaOH was
0.1412 M and the concentration of the CH3COOH was 0.1054 M . What was the pH? (Ka for
CH3COOH is 1.75 × 10–5) Give your answer to the nearest 0.01 pH unit.
Periodic Chart of the Elements
1
2
3
4
5
6
7
8
9
10
11
12
²s electronsÿ
13
14
15
16
17
18
²!!!!!!!!!!!p electrons!!!!!!!!!!!ÿ
1.008
1H
4.002
2He
²!!!!!!!!!!!!!!!!!!!!!!!!!!d electrons!!!!!!!!!!!!!!!!!!!!!!!ÿ
6.941
3Li
9.012
4Be
10.81
5B
12.01
6C
14.01
7N
16.00
8O
19.00
9F
20.18
10Ne
22.99
11Na
24.31
12M g
26.98
13Al
28.09
14Si
30.97
15P
32.07
16S
35.45
17Cl
39.95
18Ar
39.10
19K
40.08
20Ca
44.96
21Sc
47.88
22Ti
50.94
23V
52.00
24Cr
54.94
25M n
55.85
26Fe
58.94
27Co
58.69
28Ni
63.55
29Cu
65.39
30Zn
69.72
31Ga
72.61
32Ge
74.92
33As
78.96
34Se
79.90
35Br
83.80
36Kr
85.47
37Rb
87.62
38Sr
88.91
39Y
91.22
40Zr
92.91
41Nb
95.94
42M o
43Tc
101.1
44Ru
102.9
45Rh
105.4
46Pd
107.9
47Ag
112.4
48Cd
114.8
49In
118.7
50 Sn
121.8
51Sb
127.6
52Te
126.9
53I
131.3
54Xe
132.9
55Cs
137.3
56Ba
* 5770
175.0
71Lu
178.5
72Hf
180.9
73Ta
183.9
74W
186.2
75Re
192.2
76Ir
190.2
77Os
195.1
78Pt
197.0
79Au
200.6
80Hg
204.4
81Tl
207.2
82Pb
209.0
83Bi
84Po
85At
86Rn
87Fr
88Ra
**89102
103Lr
104Rf
105Db
106Sg
107Bh
108Hs
109M t
110Ds
²!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!f electrons!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!ÿ
The Lanthanide and Actinide Series (4f and 5f)
* º
4f
138.9
57La
140.1
58Ce
140.9
59Pr
144.2
60Nd
61Pm
154.4
62Sm
152.0
63Eu
157.3
64Gd
158.9
65Tb
162.5
66Dy
164.9
67Ho
167.3
68Er
168.9
69Tm
173.0
70Yb
** º
5f
89Ac
232.0
90Th
91Pa
238.0
92U
93Np
94Pu
95Am
96Cm
97Bk
98Cf
99Es
100Fm
101M d
102No
The EMF Series - Standard Potentials
The Electromotive Series (Redox Potentials).
Standard
Potential ‡
E» (volts)
Li+ + e- W Li(s)
-3.045
+
K + e W K(s)
-2.924
2+
Ca + 2e W Ca(s)
-2.76
+
Na + e W Na(s)
-2.7109
3+
Al + 3e W Al(s)
-1.706
Mn2+ + 2e- W Mn(s)
-1.029
Cd(OH)2(s) + 2e- W Cd(s) + 2OH-0.812
2+
Zn + 2e W Zn(s)
-0.7628
3+
Cr + 3e W Cr(s)
-0.74
2+
Fe + 2e W Fe(s)
-0.409
2PbSO4(s) + 2e W Pb(s) + SO4
-0.356
2+
Ni + 2e W Ni(s)
-0.23
2+
Sn + 2e W Sn(s)
-0.1364
2+
Pb + 2e W Pb(s)
-0.1263
2H+ + 2e- W H2(g)
0.0000000
4+
2+
Sn + 2e W Sn
+0.15
IO3 + 2H2O +4e W IO + 4OH
+0.15
2+
SO4 + 4H + 2e W H2SO3 + H2O
+0.20
2+
Cu + 2e W Cu(s)
+0.3419
O2(g) + 2H2O(l) + 4e W 4OH
+0.401
IO + H2O + 2e W I + 2OH
+0.485
NiO2(s) + 2H2O + 2e W Ni(OH)2(s) + 2OH
+0.49
I2(s) + 2e- W 2I+0.535
3+
2+
Fe + e W Fe
+0.770
+
Ag + e W Ag(s)
+0.7996
ClO + H2O(l) + 2e W Cl + 2OH
+0.90
+
NO3 + 4H + 3e W NO(g) + 2H2O(l)
+0.96
Br2(l) + 2e W 2Br
+1.065
+
O2(g) + 4H + 4e W 2H2O(l)
+1.229
Cl2 + 2e W 2Cl
+1.3583
+
2+
MnO4 + 8H + 5e W Mn + 4H2O
+1.507
+
Au + e W Au(s)
+1.68
PbO2(s) + 4H+ + SO42- + 2e- W PbSO4(s) + 2H2O(l)
+1.685
F2(g) + 2e W 2F
+2.87
Reduction Reaction* 6
Oxidation Reaction 7
Notes:
All ions are 1.0 M aqueous. (g) = gas at 1 atmosphere. (s) = solid and (l) = liquid.
*Reversing the reaction and changing the sign of the potential gives the oxidation reaction and the oxidation potential.
‡
The international convention of the reduction potential as the standard is followed.
Source: CRC Handbook of Chemistry and Physics, 54th Edition, CRC Press, Inc. Boca Raton, FL, p D120.
The EMF Series - Standard Potentials
Chemistry 2 Exam
Roane State Academic Festival
Answer Sheet
Team _______________________
Name_________________________________________
(PRINT NEATLY)
School ______________________
1. _______1.84 × 1024______________________
2. _______0.355 g_________________________
3. _______0.927 L_________________________
4. _______63.66 mL_______________________
5. ______24.7 L___________________________
6. _______0.570 N________________________
7. _______3NO2 ! 2 HNO3 + NO____________
8. _______2.7 × 10–1
(0.27)______________
9. _______–2469.4 kJ mol–1_________________
10. 1) The reaction shifts to the ___right_______
2) The reaction shifts to the ___right_______
3) The reaction shifts to the ___left________
11. _____7.3 × 10–7________________________
12. ____3.1 × 10–5_________________________
13. ____6.40_____________________________
14. ____2.38_____________________________
15. ____–2.041 V_________________________
Bonus: __4.82 ( the 1:1 buffer is 4.76 )________ partial credit if the got to a reasonable distance:
Starting amounts: mmoles of NaOH 1.412 mmol of CH3COOH 2.635 mmol
Ending amounts: mmoles of NaCH3OO 1.412 mmol of CH3COOH 1.223 mmol