~
CHEM 1021, Fall 2000
Prof. J. T. Roberts
Final
Dec. 19, 2000
DO NOT OPEN THE EXAM UNTIL THE PROCTOR TELLS YOU TO DO SO
Instructions :
1. There are 36 problems, each worth 5 points. They are distributed between
Parts I, II, and III (10 problems each) and Part IV (6 problems). Parts I-III
correspond to the material covered on Exams 1-3, respectively.
2. There are 17 pages, including a cover page (this page), a page of useful
constants and equations, and a periodic table.
3. Fill in the bubble sheet with your name (last namefirst) and ill number. ~ea
soft lead pencil to do this. Make sure that your answer sheet indicates the
correct test version. (This is version A). This information must be entered
correctly, or your test will not be scored properly.
4. Write the special code that is printed on your bubble sheet here: my code for
the Final is
.This is a unique code for your test. Test results and
final grades will be posted by this number only on the class web page. Grade
information will not be released over the telephone or by e-mail.
5. All of the problems are multiple choice. Mark the letter (a-e) on your answer
bubble sheet of the one choice that best answers the question. There is no
partial credit, and you need not show your work. Use scratch paper or the
backs of the exam pagesif you need spaceto work.
\
6. You are permitted to have one 8.5" x 11" sheet of paper containing any
information you wish written or printed on both sides. There is a periodic table
attached to the back of the exam.
7. You must remain seated until the exam is officially over. All answer sheets
will be collected at the same time. Hand in the answer sheet only. Keep your
copy of the examfor self-scoring.
8. The answer key will
be available
on the class home page
(http://www.chem.umn.edu/classl and follow the links) by tomorrow morning.
Test results and final grades will be posted on the class web page by Friday
afternoon.
~
J~
E
-!\
i
Final
Page 2
PART I (material
covered on first exam).
1. Which of the following
could be both an empirical and a molecular fonnula?
(a) C~1206
~~j> Ir,' c.c l
l'~
(b) N2F 4
(. ~ p , ,. I'( c.. \
i~
(c) 03
e. ~y
\~
I.,. ~ c c...
C ~~ O
t\J F l.
0
@HNF2
(e) C2~02
c
i ~
e..~1>'r'" i'c~
1..1
?"0
~---c
2. Sulfur trioxide, SO3, is made from the oxidation of SO2. The balanced equation for
the reaction is:
2 802 + 02
~
2 803
A 16 9 sample of 802 is oxidized according to the above reaction to produce 18 g of
803. What is the percent yield of 803 ?
I ",ol.f S'~
(a) 60%
A
""O~
SOJ
-
M0/-f
EIJ
1
(b) 75%
f~.(oY'"(.
"
~ i (~
~
'2,.
Mok
SOJ
(c) 80%
@90%
(e) 100%
'2t
lao
p~rc.-et\.f
3
Energy from the following
-(CH3hN2H2
reaction provided the lift for the moon lander.
+ -N2O4
~
-N2
+ -H20
+ -CO2
What is the coefficient in front ofN2 when the reaction is balanced? (Note: All
coefficients of the balanced reaction must be the lowest possible integers.)
(a) 1
(b) 2
@3
(d) 4
(e) 5
.,
-)
4
~~Ol
~
Final
Page 3
4. In which of the following compounds does the underlined element have an oxidation
number of +2?
@n(
tY'\
OH)42-
(-I
(b) .crO2C12
Cr(-4-b)
(c) HNO2
(d) :f~ +
!\J
p
(e) NO2
f\J
(+
2.)
5"')
,
-3)
(011.1)
1
~~
5. The hormone testosterone has a formula mass of288.4 g.mol- and contains 79:12%
carbon by mass. How many carbon atoms are in each testosterone molecule?
(a) 17
().:}91'J..
""yY'\\..A...):-
@3>19
(c) 21
?'.l <6 .I ~
c..-I.A t
~
\
c...~o\""I. c..
~~~
I
<6 c. ~1
\ 1. .o
I
c.. V"'"
( d) 23
( e) 28
c..( O t'Y\.)
\9
6. How many moles ofKOH are in 27.5 ml of 0.250 M KOH?
(a) 0.00431 moles
@0.00688
moles
A.?!;I"'\.{
L / lOOO r"'IJ. "'
i
0.
(c) 0.00724 moles
(d) 0.00813 moles
(e) 0.00921 moles
-
O.(JOb~(i:
r"'O
-t'J
h5'
Y"""ol
'L
(" E y
-~
Final
Page 4
7,
For an ideal gas, which of the following
statements are true?
I.
P is proportional to T at constant n and V
T
II.
P is proportional to Vat constant n and T
.(
III.
V is proportional to T at constant n and P
T
IV.
n is proportional to Vat constantP and T
,./
I/V
)
t'\u
v ...
\/
(a) I and II only
(b) III and IV only
(c) II only
(d) I and III only
~~
@,III,
and IV only
8. The correct formula for magnesium phosphate is
(a) MgPO4.
~c..~,,~s
1..\
-=
I~V"\
\'I'~
@})M~(PO4h.
(c) Mn2(PO4)3.
)-
p hos'P hc.-~.(. ~
'P
o~
( d) Mg2(PO4)3.
(e) Mn3(PO4)2.
9,
Maleic acid contains 41.4% C, 3.47% H, and 55.1% O by mass. A 0.0500 mole
sample of this compound has a mass of5.80 g. What is the molecular formula of
maleic acid?
(a) CHO
(b) C2H202
~
-1.11.1.1
, '), .(>I
t~
O )5".J
3.l11
::-}
I. ()
I
J<o.ou
~
M 'P i... I' c. ~
\
(C) C3H30
~C4fI404
(e) C~O6
forM"'-\~
M(,..
'>S
)
!o.oS-OO
~OJ
lb.
~
jV'-\o
~o
~
J~ELf-A
Final
Page 5
o.qoo
3.465
t
3. LI (,)
(a) 0.300000
(b) 0.30000
O.ZbO
-I
o.OttO
~sql
(c) 0.3000
@2».300
(e) 0.3
0.300
~~
.~
O.olloAfcrl
,~ E
y
-(:)
Final
Page
6
PART n (material covered on second exam).
11. A 150.0 9 sample ofa metal at 80.0 °C is addedto 150.0 9 ofH2O at 20.0 °C. The
final temperature of the system is 23.3 °C. Assuming that the calorimeter is a perfect
insulator, what is the specific heat capacity of the metal? The specific heat capacity
ofH2O is 4.18 J.g-I.oC-I.
-~
(a) -048 J.g-I.oC-1
.11'\.
~0.24
Cp
---:.
J.g-I.oC-1
(c) 0.48 J.g-I.oC-1
~ I
-1!rv~o~~J..Jt~.
rro.oj)
(d) 0.72 J.g-I.oC-1
(e)0.96J.g-1.oC-1
, <j~-O
:
-O.:Z.I.I
T/1.oc
'7..3. 3°C. -~oBc:..)
~'
12. The properties of a real gas are most likely to deviate from those of an ideal gas when
(a) the pressure is low.
(b) the temperature is high.
@ the pressure is high and the temperature is low.
( d) the pressure is low and the temperature is high.
(e) All of the situations (a)-(d) would result in significant deviation from
ideality .
13. Three 1.0 L flasks are filled with H2, 02, and NH3, respectively, at STP. Which of the
following statementsis true?
@
All flasks have the samenumber of gas molecules. Av\) ~c..JY"(). ..s
1c...1..A.)
(b) The average speedsof the gas molecules are the same in all of the flasks.
(c) The densities of all the gasesare the same.
( d) There are half as many H2 molecules as NH3 molecules.
(e) None of the above statements(a)-(d) is true.
Final
Page 7
14. Given the following data, calculate the heat required to convert solid sulfur to gaseous
sulfur at 298 K and 1 atm pressure.
S(s) + O2 (g) ~
S02 (g)
LVJ;98K = -395 kJ
S(g) + O2 (g) ~
S02 (g)
LVJ;98K = -618 kJ
(a) -1013 kJ.mol-l
(b) +618 kJ.mor1
~
~ ( S)
.,.
(c) -618 kJ.mol-l
-)
J
L
S '>d"ll 1.(~)
-)
/
(d) -223 kJ.mol-l
@223
/
C~)
0
~(~)
G
1
-;)
-~ /
~ ()/~ ( ~)
~b
c.)
/<6
1( J
k
J
-
kJ.mor1
-)
s(S)
5(~)
15. The number of molecules in 10.0 liters of air at 0 °C and 1.0 atm pressure is
(a) less than 1020.
Y\ ~ .-.,..
rv:
(b) between 1020and 1021.
(c) between 1021and 1022.
h :-
( \.
(d) between 1022and 1023.
@etween
1023and 6 x 1023.
t\)=
(O.l\llb
r"\O\
16. Which of the following atoms has the smallest atomic radius?
(b)
Ca
(c)
As
(d)
At
"13
k'
1<
O .l{ L I ~ rV\() \
() '\ J /
Ha
/r"tcl~
~I
n:
(a)
L .c..~"
(,)lJ :
~
1..~ "'110
/) e \'f -j),
Final
Page 8
17. What is the energy contained in a single quantum of orange light with a frequency of
5.00 x 1014S-l?
(a) 1.25 x 10-48J
~ -=
Vh)n.31xI0-19J
~
(c) 1.88 x 105 J
h
:
(d)3.13xI013J
U-
( ~. b3 ~
:
3.3
."
-1 LI1 - ~
\0
I 1-
J
-1'1
\0
"1
(e) 6.02 x 1023J
19. Which of the following sets of quantum numbers are allowed?
!1
1
ll1l
11
10
-7
+1/2
II.
4
3
O
-1/2
III.
3
2
1
+1/2
I.
(a) lonly
(b) II only
(c) III only
(d) I and II only
m.r.
'1.C.S
'1.(.5
'1~..S
"
01"9
s
I~£
y
-
Final
Page 9
20. Which ofthe following
third electron?
~g
(b)
atoms has the highest ionization energy for removal ofthe
( rJ
Il's
/v1j I
be.cc...l,..,st
~A(
3-
~/~(fY'oV\
Al
c.. ~ J
.(OM~
J
r '.C)M
c...n
f\
-=.
z.
J.e
\I-{
I
(c) Sl
( d) Cl
(e) Ar
I~
1.~
,..s
i S O of...l.(c.~ Y'O I"\ I' <..
\.A..)I ~ h
~
~~;:::
}\Je
(J
Final
Page 10
PART ill (material covered on third exam).
21. Which of the following speciesis best described by two or more resonance
structures?
(d)
(b)
(e)
H-~N
~c,
H~/C...".CH3
(c)
F--r-F
F
22. In the acetylene, C2H2, molecule, there are
(a) five a bonds.
(b) two a bonds and three 1t bonds.
J-J -c.
-:=: c.. -l
(c) five 7t bonds.
r...'
~
0--
0--",
( d) four 0' bonds and one 7t bond.
'2..1't'
4
~
0-
~
---
I~
E
'1'
-
r>r
Final
Page
25. The 0-0-0
12
angle in ozone, 03, is
(a) 180°.
(b) 120°.
(}
@slightly
less than 120°.
if'
"
l::--3
~(.(~C..~\'\.I~
?",-lV'j'
.0,
(d) 109.5°.
(e) slightly less than 109.5°,
26. Which of the following
(a) 2 CH30H
is a substitution reaction?
+ 3 02
(b) C2~
+ 3 02
(c) C2~
+ Cb
~
W2lI6
+ Cb
~
( e) HCOOH
~
~
~
'-
2 C02 + 4 H20
2 CO2 + 2 H20
C2~Cb
C2HsCI + HCI
+ CH30H
~
HCOOCH3
+ H20
27. How many valence electrons does a sulfate ion have?
(a) 18
(b) 20
'1,.-
(,
~OLJ
\
(c) 24
~
""
Ll
(, e- J
...
~
S
0
( d) 26
~2
28. For which of the following
@1<8)
+ e- -+
(b)h(8)
(c) I(g)
(d) N~g)
-+
-+
r (8)
21(8)
r (g) .-1-e"
+ l(g)
(e) N3(s) +
reactions is AH equal to the electron affinity ofl?
-+
~ h(s)
Nal{s)
-+
Nal{s)
"'2-.e..
t
~~e..
Final
Page 13
29. Which ofthe following
molecules has a non-zero dipole moment?
l(a~OOH
~.L
(b) CO2
..,~.
L/ --
, "\.
,1 /
0
'\\
(c) HCCH
(d) SF6
..
-(
-O
4
~
-C-~
(e) PFs
C.--
F
\J
,= -I
r::- --S
---1'"=:
-r::
F
j':.
I.
f
1--=
:::?
-F
I
r:
30. In the hydronium ion, H30+, VSEPR theory predicts that the valence electro~r~
arranged about the central oxygen atom at the comers of a
.
..J
(a) pyramid@
tetrahedron.
Ll
vc..l~ I'\('.(
..
1>~ iv .s
I.} -<?
-H
( c) trigonal plane( d) bent structure.
( e) square plane.
11
~
}<ty-
A
Final
Page 14
PART IV (material
covered since the third exam).
31. Which of the following
compounds is an ether?
(a) CH3COCH3
I
(b ) CH300CH3
~
-0
-~
@CH30CH3
( d) CH3CH2OH
(e) CH3COOH
~<~
32. Na20 forms an antifluorite cubic lattice in which the negative ions form a facecentered cubic lattice and the positive ions occupy all tetrahedral sites. The number
of sodium ions in a single unit cell is
(a)
3
[cc.
(b)
4
(c)
6
-t( ~)
<6}
"
~
1
c. (3 (' n.c. .~
( c...t(.
@8
(e)
12
,0
LI c..10"",5
C.f...
p-er
1Jc... .t
p-.tr
33. Which of the substancesbelow has the highest boiling point?
(a) CH3CH2CH3
(b) CH3CH2CH2CH3
(c) CH30CH3
@CH3CH20H
(e) CH3CH2F
'h1Jrc~~V\
\:>oV\J.s
II
, ~o-5
1" f
y
Final
Page 15
34. Neon atoms do not combine to form Ne2 molecules, yet neon atoms can be liquified
through the following intermolecular forces:
(a) dipole-dipole.
(b) ion-dipole.
(c) dipole-induced dipole.
~ondon
dispersion.
(e) nonmetal-nonmetal.
~c~
35. In a certain mountain range, water boils at 91 °C. What is the pressureunder t1lese
conditions? The enthalpy ofvaporization ofwater is 44.0 kJ.mol-l.
@535 torr
(b)575torr
A
Y\
(c) 615 torr
f1. \ -I?J:
fl
) -R
l=.
(d) 645 torr
)Y\
\
}..
I,
( e) 685 torr
lOfr
36. At room temperature and pressure, SiO2 is an example of
(a) a polar molecular gas.
(b) a nonpolar molecular gas.
@)).
covalent network solid.
( d) an ionic solid.
( e) a metallic solid.
)
IL
LI 4 OOOJ/ ~()
? bO ~otr ) ,,-
V'l..
-..J
-A