Oregon State University, Summer 2009 Chemistry 121
Final Exam, July 10th, 10 am
DO NOT OPEN THIS EXAM UNTIL INSTRUCTED.
CALCULATORS ARE NOT TO BE SHARED.
Instructions :
You should have with you several number two pencils, an eraser, your notecard, your University ID Card,
and a calculator. If you have other notes with you, place them in a sealed backpack and place the backpack
OUT OF SIGHT.
Fill in the front page of the Scantron answer sheet with your last name, first name, middle initial, and student
identification number. Leave the class section number and the test form number blank.
This exam consists of 25 multiple-choice questions. Each multiple-choice question has 5 points associated
with it. Select the best answer by filling in the corresponding circle on the rear page of the answer sheet.
If you have any questions before the exam, please ask. If you have any questions during the exam, please
raise your hand to attract the attention of a proctor. The proctor will come to you.
Open and start this exam when instructed. Present your ID card when submitting the exam. Place your openended portion of this exam in the appropriate stack. You may keep the this exam, so please mark the answers
you selected on it.
Scoring :
25 multiple-choice questions @ 5 pts each
= 125 pts
Information provided
A periodic table, a list of polyatomic ions, solubility rules and a list of strong acids and bases, and oxidation
number rules are provided on the next four sheets. Check to see that you have them.
Conversion factors
1 L = 1000 cm3
NA = 6.022 × 1023
c = 3.00 × 108 m / s
h = 6.626 × 10 -34 J s
Some possibly useful formulae:
∆E = q + w
∆H = qp ∆E = qv w = - P∆V
For light waves : λ = c / ν
∆E = h ν = h c / λ
λ=h/mv
q = m C ∆T
Group
1
2
3
4
5
6
7
1A
2A
3B
4B
5B
6B
7B
KEY
Atomic number !
Symbol !
Atomic mass !
1
1
H
1.00794
2
3
4
5
6
7
3
4
Li
Be
6.941
9.01218
8
9
10
8B
11
12
13
14
15
16
17
18
1B
2B
3A
4A
5A
6A
7A
8A
2
1
He
H
4.00260
1.0079
5
6
7
8
9
10
B
C
N
O
F
Ne
10.811
12.011
14.0067
15.9994
18.9984
20.1797
11
12
13
14
15
16
17
18
Na
Mg
Al
Si
P
S
Cl
Ar
22.9898
24.3050
26.9815
28.0855
30.9738
32.066
35.4527
39.948
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
K
Ca
Sc
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
Ga
Ge
As
Se
Br
Kr
39.0983
40.078
44.9559
47.88
50.9415
51.9961
54.9381
55.847
58.9332
58.69
63.546
65.39
69.723
72.59
74.9216
78.96
79.904
83.80
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
Rb
Sr
Y
Zr
Nb
Mo
Tc
Ru
Rh
Pd
Ag
Cd
In
Sn
Sb
Te
I
Xe
85.4678
87.62
88.9059
91.224
92.9064
95.94
(98)
101.07
102.906
106.42
107.868
112.411
114.818
118.710
121.75
127.60
126.9045
131.30
55
56
57-71
72
73
74
75
76
77
78
79
80
81
82
82
84
85
86
Cs
Ba
Hf
Ta
W
Re
Os
Ir
Pt
Au
Hg
Tl
Pb
Bi
Po
At
Rn
132.905
137.327
* Rare
Earths
178.49
180.948
183.85
186.207
190.23
192.22
195.09
196.9665
200.59
204.37
207.2
208.9804
(209)
(210)
(222)
110
111
(269)
(272)
87
88
89-103
104
105
106
107
108
109
Fr
Ra
^
Rf
Ha
Sg
Ns
Hs
Mt
(223)
226.025
Actinides
(261)
(262)
(263)
(262)
(265)
(266)
*Lanthanide
Series
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
La
Ce
Pr
Nd
Pm
Sm
Eu
Gd
Tb
Dy
Ho
Er
Tm
Yb
Lu
138.906
140.12
140.9077
144.24
145
150.4
151.96
157.25
158.9254
162.50
164.9304
167.26
168.9342
173.04
174.967
^Actinide
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
Series
Ac
Th
Pa
U
Np
Pu
Am
Cm
Bk
Cf
Es
Fm
Md
No
Lr
227.028
232.0381
231.0359
238.029
237.0482
(244)
(243)
(247)
(247)
(251)
(254)
(257)
(258)
259
262
Strong Acids
HCl, HBr, HI
HNO3
HClO4
H2SO4
Strong Bases
LiOH, NaOH, KOH
Ca(OH)2
(slightly soluble)
Ba(OH)2
Sr(OH)2
CH121 Summer 2009 Final
OXIDATION NUMBER RULES
• The oxidation number of a free element is always 0.
• The oxidation number of a monatomic ion equals the charge of the ion.
• The oxidation number of fluorine in compounds is -1.
• The oxidation number of hydrogen in compounds is +1.
Exception: the oxidation number of hydrogen is -1 in metal hydrides, like CaH2.
• The oxidation number of oxygen in compounds is -2.
Exception: the oxidation number of oxygen is -1 in peroxides, like BaO2.
• The oxidation number of Cl, Br, I in compounds is -1.
Exception: when combined with O or F, the preceding rules apply.
The oxidation numbers of all other elements in a compound adjust such that:
• The sum of the oxidation numbers of all of the atoms in a neutral compound is 0.
• The sum of the oxidation numbers in a polyatomic ion is equal to the charge of the ion.
3
CH121 Summer 2009 Final
Midterms Material
1.
What is the correct value for V to the correct number of significant figures?
V = (4/3)πr3
a.
b.
c.
d.
e.
2.
π = 3.1412
r = 2.000 cm
3
3 × 10 cm
3.3 × 101 cm3
33.50 cm3
33.51 cm3
33.506 cm3
I drop an iron nail weighing 25 g into a beaker of oil with a density of 0.80 g/mL. The volume of the
oil increases by 3.2 mL. What is the density of iron?
a.
b.
c.
d.
e.
3.
2
0.80 g/mL.
1.0 g/mL.
7.8 g/mL.
9.8 g/mL.
25 g/mL
Which of the following statements is CORRECT?
a. The 13C nucleus has 7 protons and 6 neutrons.
b. The element with an isotope that has a mass number of 40 and equal numbers of protons and
neutrons is Ca.
c. A neutron has almost the same mass as a proton, but the opposite charge.
d. An electron has the same charge as a proton.
e. Hydrogen has only one isotope – 1H.
4.
The charges on the monatomic ions of P, F, Rb and Al are:
a.
b.
c.
d.
e.
5.
-3, -1, +1, +3
+3, +1, -1, -3
-2, -1, +2, +3
-1, -2, +1, +2
-3, -2, +2, +3
What is the correct name of the compound, FeSO4?
a. Iron (II) sulfite
b. Iron sulfoxide
c. Iron (III) sulfide
d. Iron (III) sulfate
e. Iron (II) sulfate
4
CH121 Summer 2009 Final
6.
When the following equation is correctly balanced what is the ratio of moles of water produced to
moles of oxygen (O2) that are consumed?
__ C4H4(g) + __ O2(g) Æ __ CO2(g) + __ H2O(l)
a.
b.
c.
d
e.
7.
4/5
4/1
2/4
3/5
2/5
How many grams of hydrogen are needed to reduce 10.0 g of tungsten oxide (WO3, 231.8 g/mol) to
tungsten metal?
WO3(s) + 3H2(g) Æ W(s) + 3H2O(l)
a.
b.
c.
d.
e.
8.
If I dissolve 24.2 g of Fe(NO3)3 (molar mass = 241.9 g/mol) in 500 mL of water, what is the
concentration of nitrate ions in the resulting solution?
a.
b.
c.
d.
e.
9.
0.261 g
0.0870 g
0.130 g
1.008 g
0.329 g
0.200 M
0.100 M
0.600 M
0.300 M
0.500 M
Which of the following compounds will produce a precipitate when mixed with Ba(NO3)2(aq)
solution?
1. NaOH(aq) 2. O2(g) 3. Pb(NO3)2(aq)
a.
b.
c.
d.
e.
4. HCl(aq)
1 only
4 only
1 and 4
All of them
None of them
5
CH121 Summer 2009 Final
10.
Which of these statements is CORRECT?
a.
b.
c.
d.
e.
11.
Acids react with carbonates to make carbon dioxide.
Oxidation is electron gain.
A spectator ion is one that forms a precipitate.
A base increases the concentration of protons in solution.
Molarity is the number of moles of solute per liter of solvent.
Which species are oxidized/reduced in the following reaction?
Mg(s) + 2HCl(g) Æ MgCl2(aq) + H2(g)
a. Mg and Cl in HCl are both reduced.
b. Mg is oxidized and H in HCl is reduced.
c. Cl in HCl is oxidized and H in HCl is reduced.
d. H in HCl is oxidized and Mg is reduced.
e. This is not a redox reaction.
12.
Which of the following statements about a titration is INCORRECT?
a. The equivalence point of an acid-base titration can be detected by the choice of the correct
indicator.
b. A volumetric flask contains an accurate volume of liquid.
c. An acid-base titration can work if you add either base to acid, or acid to base.
d. Titrations of the same volumes of 1 M HCl or 1 M H2SO4 will both require the same volume of 1
M NaOH for neutralization.
e. Titrations can be used for redox reactions as well as acid-base reactions.
13.
I perform the following acid/base neutralization titration.
HCl(aq) + NaOH(aq) -------> NaCl(aq) + H2O(l)
25.0 mL of hydrochloric acid solution of unknown concentration required 50.0 mL of 1.00 M sodium
hydroxide solution to be neutralized. What is the concentration of the acid?
a. 0.50 M
b. 1.00 M
c. 2.00 M
d. 2.50 M
e. 5.00 M
6
CH121 Summer 2009 Final
14.
Which of the following statements is CORRECT?
a. Energy is the capacity of a body to keep a constant temperature.
b. Kinetic energy refers to the energy possessed by virtue of the position of a body in the
gravitational field of the Earth.
c. Potential energy can never be converted into kinetic energy.
d. Energy can be created or destroyed in chemical reactions.
e. The kinetic energy of molecules of ice is less than that of molecules of room temperature water.
15.
I heat a 55.9 g piece of Fe (specific heat = 0.449 J / g K) heated to 250 °C, then drop into a
thermostatted water-bath maintained at 30 °C. What is the value of the heat q transferred from the
Fe to the water when the Fe has come to the temperature of the bath?
a.
b.
c.
d.
e.
16.
If a gas expands during a constant pressure chemical process during which heat flows out of the
system, which of the following is statements is CORRECT ?
a.
b.
c.
d.
e.
17.
+5.52 kJ
-5.52 kJ
– 98.8 J
-6.27 kJ
+ 5.52 J
q is positive and w is negative
q is negative and w is positive
q is positive and w is zero
q is negative and w is negative
q is zero and w is positive
Which of the following statements is INCORRECT?
a. The 1st Law of Thermodynamics is: ∆E = q + w.
b. Enthalpy is the heat transfer at constant volume.
c. When ∆H is negative, the process is exothermic.
d. During a phase change the temperature does not change.
e. If the heat of vaporization is x J/g, then the heat change when 1 g of the substance condenses from
the gas to liquid is –x J/g.
7
CH121 Summer 2009 Final
18.
Given the following reactions and enthalpy changes,
)H = -393.5 kJ
)H = -890.3 kJ
)H = -285.8 kJ
C(s) + O2(g) ÿ CO2 (g)
CH4(g) + 2O2(g) ÿ CO2 (g) + 2H2O(l)
H2(g) + ½ O2(g) ÿ H2O(l)
use Hess’s Law calculate the enthalpy changes under standard conditions associated with the reaction
C(s) + 2H2(g) ÿ CH4(g)
a.
b.
c.
d.
e.
)H = ?
- 998 kJ
+ 74.8 kJ
-74.8 kJ
-211 kJ
+211 kJ
19. Calculate the standard enthalpy of combustion of benzene (C6H6) give the following data.
C6H6 (l) + 7.5O2 (g) Æ 6CO2 (g) + 3H2O (l)
given the following enthalpies of formation :
∆Hof (kJ/mol) C6H6 (l) = +49.0
CO2 (g) = -393.5
H2O (l) = -285.8
(HINT : why is the value for O2(g) missing?)
a.
b.
c.
d.
e.
20.
-2696 kJ
-3512 kJ
-3267 kJ
-3169 kJ
-2897 kJ
Arrange the following segments of the electromagnetic spectrum in order of increasing frequency.
1. AM radio 2. X-rays
a.
b.
c.
d.
e.
3. Ultra-violet 4. Infra-red
1, 2, 3, 4
4, 3, 2, 1
1, 3, 4, 2
1, 4, 3, 2
3, 2, 1, 4
8
CH121 Summer 2009 Final
21.
What is the energy contained in one photon from a UV laser that has a wavelength of 250 nm
a.
b.
c.
d.
e.
22.
7.95 × 10 -28 J
6.63 × 10-34 J
7.95 ×10 -19 J
250 J
7.95 × 10 -19 kJ
The diagram shows some transitions between energy levels in the H atom. Order the transitions by
increasing wavelength.
a.
b.
c.
d.
e.
C, A, B
B, C, A
A, C, B
C, B, A
B, A, C
n=4
n=3
A
C
n=2
B
n=1
23.
Which of the following represents an allowable set of quantum numbers?
a.
b.
c.
d.
e.
24.
n = 2, l = -2, ml = 2
n = 3, l = 3, ml = -3
n = 1, l = 0, ml = -1
n = 2, l = 1, ml = -1
n = 0, l = 0, ml = 0
The principal quantum number (n) and the magnetic quantum number (ml) determine respectively
a.
b.
c.
d.
e.
The size and orientation of an orbital.
The orientation and shape of an orbital.
The shape and size of an orbital.
The size and shape of an orbital.
The shape and orientation.
9
CH121 Summer 2009 Final
25.
Select the correct list of orbital names for the following orbitals:
a.
b.
c.
d.
e.
s, dz2, py
dxy, s, pz.
py, s, dz2
py, s, dx2-y2
s, dxz, pz
10