CHEM 107 (Spring-2004)
Exam 1 (100 pts)
Name: ------------------------------------------------------------------------, SSN -------------------------------LAST NAME, First
(Circle the alphabet segment of your LAST NAME): A-C
D-H
I-L
M-O
P-Z
Please answer the following questions:
Part I: Multiple Choices (48 pts: 16 @ 3 pts each). Circle the ONE best answer:
1. Perform the indicated operations and give the answer in cm with the proper number of significant
figures.
12.64 cm – 48 mm + 0.246 m = ?
a) 42.0
b) 32.44
c) 32.4
d) 42
2. Two atoms are 154 pm apart. Express this distance in cm.
a) 1.54 x 10-8
b) 1.54 x 10-10
c) 1.54 x 10-12
d) 1.54 x 108
3. Which of the following does not represent a chemical property?
a) flammability in air
b) burning gasoline
c) boiling an egg
d) solubility in water
4. Convert 1.39 ft/s to meters per minute (1 m = 39.37 in).
a) 1520
b) 305
c) 2.12
d) 25.4
5. A bottle containing 500 mL of ketchup has a density of 1.43 g/mL. What is the mass of the bottle
in grams?
a) 350
b) 715
c) 71.5
d) 501
6. Taken by itself the fact that 8.0 g of oxygen and 1.0 g of hydrogen combine to give 9.0 g of water
demonstrates what natural law?
a) Conservation of Mass
b) Constant Composition
c) Periodicity
e) Multiple Proportions
7. What is the nuclear symbol for a species which contains 57 neutrons and has a mass number of
101?
a) Er
b) Ru
c) Md
d) Os
1
8.
Predict the product of the reaction of aluminum, Al with selenium, Se.
a) Al2Se3
b) Al3Se2
c) AlSe
d) AlSe3
9. Which of the following statements about the periodic table is incorrect?
a)
b)
c)
d)
Group 17 is the only group which has the three physical states of matter.
Group 18 is called noble gases group
Group 1 is called alkali metals
Non of the above
10. Calculate the mass of a single Mg atom (atomic mass = 24.30 amu)?
11.
12.
a) 4.035 x 10-23
b) 4.035 x 10-25
c) 1.661 x 10-24
d) 2.478 x 10-24
What is the number of molecules that contained in 1.598 g sample of Br2 (molar mass of Br2 =
159.8 g)?
a) 6.022 x 1023
b) 0.01
c) 6.022 x 1021
d) no answer was given
All of the following statements are true EXCEPT
a)
b)
c)
d)
13.
a proton carries a +1 charge and an electron carries -1 charge.
a neutron is an uncharged particle with a mass slightly greater than a proton.
more than 99.9% of an atom’s mass is concentrated in the nucleus.
the nucleus of an atom has a negative charge.
How many electrons, protons, and neutrons are found in a Cl- ion formed from 35Cl?
a)
b)
c)
b)
14.
17 electrons, 16 protons, 19 neutrons
17 electrons, 17 protons, 18 neutrons
18 electrons, 17 protons, 18 neutrons
18 electrons, 18 protons, 18 neutrons
Naturally occurring lithium consists of two isotopes Li-6 and Li-7. The atomic mass of Li is
approximately 6.9. What are the reasonable estimate of the relative percentages of Li-6 and Li-7,
respectively?
a) 10, 90
15.
c) 50, 50
d) 90, 10
c) PF3
d) CaCl2
Which of the following compounds is ionic?
a) SF6
16.
b) 25, 75
b) PCl3
Calculate the mass in grams of 0.100 moles of Ca(OH)2?
a) 5.71
b) 7.41
c) 6.022 x 1022
d) 1.35 x 10-3
2
Part II. Names, formulas and properties (28 pts: 14 @ 2 pts each) – NO Partial Credits
1. (16 pts) Complete the following table with the formula or the name of the compound
Name
Vanadium(III) nitrate
Lithium carbonate
Calcium nitride
Sulfuric acid
Formula
CoF3
P2S5
Na3PO4
HF (aq)
2. (12 pts) Consider the following substances: Cl2, CaO, HBr, CuCl2, AsCl3, NaNO3 and NO2:
a) Which are molecular (covalent)?
----------------------------------
b) Which are diatomic?
------------------------------------
c) Which are triatomic?
------------------------------------
d) In which we do find only electron sharing?
------------------------------------
e) Which compound is derived from a transition metal?
------------------------------------
f) Which compound is derived from a metalloid element?
-------------------------------------
Part III. Calculations (24 pts): Show all work for full credit. Please express all answers with the
proper units and correct number of significant figures.
1. (8 pts) Naturally occurring copper is composed of two isotopes. One of the isotopes has an atomic
mass of 62.9396 amu and 69.17% abundance. What is the atomic mass of the other isotope?
Atomic mass of the
second Cu isotope
3
2. (16 pts) Strychnine, a deadly poison, has a molecular mass of 334 and a percentage composition
75.42% C, 6.63% H, 8.38% N and the balance oxygen. Calculate:
a) the simplest formula of Strychnine
b) the molecular formula of the compound
a) Simplest formula
b) Molecular formula
4
PREFERENCE SHEET FOR
CHEM 107
Exam 1 – Spring 2004
You will have 60 minutes to complete this exam. The exam has 4 pages plus the Periodic Table
Reference page.
When you are told to do so, tear off the Periodic Table cover sheet and use as required during the
exam.
1.
Useful
Information:
T (˚F) = 1.8 T (˚C) + 32˚
d=m/V
Avogadro’s Number, NA = 6.022 x 1023
1
1
2
H
Periodic Table of the Elements
He
1.01
3
2
3
4
5
6
4.00
4
5
6
7
8
9
10
Li Be
B
C
N
O
F
Ne
6.94
9.01
10.81 12.01 14.01 16.00 19.00 20.18
11
12
13
14
15
16
17
Na Mg
Al Si
P
S
Cl Ar
22.99 24.30
26.98 28.08 30.97 32.06 35.45 39.95
21
19
20
K
Ca Sc Ti V
39.1
40.08 44.96 47.88 50.94 52.00 54.94 55.85 58.93 58.69 63.55 65.38 69.72 72.59 74.92 78.96 79.90 83.80
37
38
39
Rb Sr Y
22
40
23
41
24
25
26
27
28
29
30
31
32
33
34
35
18
36
Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
42
43
44
45
46
47
48
49
50
51
52
53
Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I
54
Xe
85.47 87.62 88.91 91.22 92.91 95.94 (98)
101.1 102.9 106.4 107.9 112.4 114.8 118.7 121.8 127.6 126.9 131.1
55
76
56
57
72
73
74
75
77
Cs Ba La Hf Ta W Re Os Ir
78
79
80
81
82
83
84
85
86
Pt Au Hg Tl Pb Bi Po At Rn
132.9 137.3 138.9 178.5 181.0 183.8 186.2 190.2 192.2 195.1 197.0 200.6 204.4 207.2 209.0 (209) (210) (222)
87
7
88
89
104 105 106 107 108 109 110 111 112
Fr Ra Ac Rf Db Sg Bh Hs Mt Uun Uuu Uub
(223) 226.0 227.0 (261) (262) (263) (262) (265) (266) (269) (272) (277)
58
59
60
61
62
63
64
65
66
67
68
69
70
71
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
140.1 140.9 144.2 (145) 150.4 152.0 157.2 158.9 162.5 164.9 167.3 168.9 173.0 175.0
90
91
92
Th Pa U
93
94
95
96
97
98
99
100 101 102 103
Np Pu Am Cm Bk Cf Es Fm Md No Lr
232.0 231.0 238.0 237.0 (244) (243) (247) (247) (251) (252) (257) (258) (259) (260)
5
6