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Chemistry 1201 Section 4
Spring 1999
Professor Russo
Exam #2
Type of exam: In class. You can use your cheat sheet and a calculator. In most cases, vital
constants and conversion factors are supplied.
Covers: Chapter 1 and first part of Chapter 2. Most problems are slight modifications of
those assigned as homework. Numbers have been changed, and the problems have been
adapted to multiple choice.
Duration: 1 hour.
Value: 100 points. Each question is worth 10 points.
Instructions: Relax! You have already worked these problems, right? Since we are splitting
Chapter 2 down the middle, you are only held responsible for material covered during lecture
(atomic structure). Mark your answers on a LARGE scantron using a #2 pencil. Be sure to
write and bubble in your name! Fill out the scantron just before turning it in. You can mark
the right answers directly on this exam until you are sure you have the answer you wish to
select.
Correct Answers: Posted outside my office immediately after exam.
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Question #1. (based on BLB Text 1.4) Air is a:
a) homogeneous mixture (otherwise known as a solution)
b) a compound
c) an element
d) a pure substance
Question #2. (based on BLB Text 1.18) 8.3  10-9 meters is:
a) 83 pm
b) 0.83 km
c) 8.3 m
d) 8.3 mm
e) 8.3 nm
Question #3. (based on BLB Text 1.30) In Moose Lake, Minnesota, the temperature can fall
to -55oF (and wind chill is even worse!). Express that in Kelvins (assume exact numbers).
a) -285.5 K
b) 224.8
c) -48.3 K
d) -156.6 K
Chem 1201 Sec. 4
Exam #1
Page 1
Question #4. (based on BLB Text 1.34) How many significant figures are there in the
measured time, 4,780,800 s?
a)
b)
c)
d)
7
4
5
6
Question #5. (based on BLB #1.46) The Ford Mustang was originally sold with a very nice,
small block V8 engine that displaced 289 cubic inches. Express this displacement in liters.
(Hint: 2.54 cm = 1 inch).
a) 734 L
b) 0.176 L
Dark blue Mustang coupe, just like the one my friend
c) 0.734 L
had growing up in Denver. Driven with juvenile
d) 4.74 L
insanity, it could leave more powerful Chevrolet's in a
heap of Drive-In dust on the way to late night cruises.
Question #6. (based on BLB #1.28) Gold can be hammered into very thin sheets. Suppose
2.00 grams of gold are hammered into a rectangle that is 12.0 inches wide by 18.0 inches long.
If the density of gold is 19.32 g/cm3, what is the thickness of this sheet of gold in centimeters?
(2.54 cm = 1 inch).
a) 7.43 x 10- 5 cm
b) 4.79 x 10-5 cm
c) 7.43 x 10-7 cm
d) 4.79 x 10-7 cm
e) 1.89 x 10-7 cm
Chem 1201 Sec. 4
Exam #1
Page 2
Question #7. (based on BLB Text 2.12) 1.00  1012 phosphorous atoms laid end to end would
form a line 1.10  102 meters long. What is the diameter of a single phosphorous atom in
nanometers?
a) 1.10  1010
b) 0.909
c) 0.110
d) 110  10-10
e) 9.09
Question #8. (based on BLB Text 1.63-c) Which weights more, a brass sphere with a radius
of 2.37 cm or a gold sphere with a radius of 1.93 cm? The density of brass is 8.47 g/mL and the
density of gold is 19.32 g/mL. (Reminder: the volume of a sphere of radius R is given by V =
4R3/3).
a) The brass sphere weighs more.
b) The gold sphere weighs more.
Chem 1201 Sec. 4
Exam #1
Page 3
Question #9. (based on BLB Text 2.8) A physicist named Dweeb living on the planet Geek
performed an experiment just like Millikan's. However, on Geek the units for charge had
previously been established as Dorks instead of Coulombs. Dweeb observed just three oil
drops: 3.900  10-23 dorks, 5.200  10-23 dorks; and 9.100  10-23 dorks. Based on these very
limited data, which answer below is the best guess for the charge on an electron? Hint: this
problem is somewhat easier than the one in the textbook because, while Dweeb was very lazy
and only observed three drops, he made very precise measurements.
a) 1 electron = 1.800  10-24 dorks
b) 1 electron = 2.400  10-24 dorks
c) 1 electron = 5.000  10-24 dorks
d) 1 electron = 1.300  10-23 dorks
e) 1 electron = 1.100  10-23 dorks
Question #10. (based on BLB Text 2.32) Only one column in the table below contains truly
correct information. Which one?
a)
b)
c)
d)
e)
52
130 -1
98
98
118
Cr 3+
I
Tc -1
Hg +1
Sn
Symbol
24
50
43
82
50
Protons
24
80
55
126
68
Neutrons
21
51
44
81
51
Electrons
+3
-1
-1
+1
0
Net Charge
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There! You made it through your first in-class exam. Things I hope you noticed:
 The assigned problems re-appeared.
 Only assigned problems covering material that we discussed in class are used. (Later, you
should go back and rework some of those other Chapter 2 problems).
 I deliberately asked some of the problems that students asked me in my office or during
help sessions.
 I have to convert the problems to multiple choice. You can try this at home! Make up your
own practice exams within your ChemTEAMS.
 Constants are usually provided, but not important equations.
Chem 1201 Sec. 4
Exam #1
Page 4