1. (24) a. 2
In the
diagr
am below to the to the right, helium atoms are represented by unshaded spheres,
neon
atoms
by gray spheres, and argon atoms by black spheres. If the to tal pressure
in
the container
is
900
mm
Hg,
wh
at is the
parti~ressure
of
helium?
A) 90
mm
Hg
~
180
mm
HgC
) 270 mm Hg D) 450
mm
Hg • 0
o
O.
b.
Which
of
the following is not a
~
e
function?
A) enthalpy ® h
eat
C) internal energy D) volume o
.0.
c.
Which
one
of
the
followin
g~
ses
will have the high
est
rate
of
effusion?
A)
N02
~
N20 C)
N204
D)
N03
SF("
'$
,..""I
"'
DI
A-r::
Q09/mol
d.
At
what
temperature will sulfur hexafluoride molecules have the same average speed as argon atoms
at 20
°C
?
JGt3
r:.
A)
-2ZJ(6
B)
73.
2°
C
C)
381
°C @ 799°C
e.
Whi
ch
substance
in
each
of
the following pairs is expected to have the larger dispersion forces?
I B
rZ
o r I Z
'"
""o'o....r~SS
~
A) Br2
in
set I and n-butane in
set"
H H H H
B) Br2
in
set 1 and isobutane in
set
II
I I I I
I I
E-t-
C
----,:::-C-
C-
H
©
12
in
set I and n-butane
in
set"
I I I I
D)
12
in
set I and isobutane
in
set
II
H H H H
H-
C-
C---C
-H
n-
bu t
an
e I I I
H H H
l.sDbut
a
na
f. The magnitude
of
the heats
of
v
apor
ization, fusion and SUblimation
of
a S
Ub
stance reflect the
A) density
of
the substance.
B) magnitudes
of
the boiling and melting points
of
the substance.
~
strength
of
the covalent bonds between atoms
in
each molecule
of
the substance.
19J
strength
of
the intermolecular forces
of
the substance.
g.
When
a substance melts at its normal melting point, the sign
of
6.
H
is
;-
and the sign
of
6.
S
of
this phase change is
.r
A) + , - B) - , + @ + , + D) - , -
h. Which
of
the following has the
~
t
est
(most negative) lattice energy?
A)CH4
~
CaC
03
C) NaCI D) KBr
2. (6) Bromine is one of only two
elements
that is a liquid at room temperature. Bromine has a heat
of
vaporization of 30.
91
kJ/mol and its boi
li
ng point is 59 °C .
What
is the entropy
of
vaporization for
br
omine?
®
.66~O
-
6fi-TbS
O~
3()·91
-
(;}13t-S"Jk.
-
&5
o r H
I
3.
(10) Use bond strengths given on the cover page to determine the heat
of
combustion for octane
(CS
H18)
.
~
I,""
\f
~
W-
V
~
~
J.J
JG"._.. _
~
~
r-
-
C-
-
C-c,-
L - t
-(..
-c
- c
-,I
+-
...
0=-0
~
lfa
0
=c=:'o
+ Ii
1+-0-1-1
o I
~
~
~
,~
t\.
~
~
~
.'
.'
.1
H-
~
~'O
~o~
-bond
~
~~
-=f\4 (.-c
.,..
3lL
c.-t-}-
+-
J5"
o=oJ
-[.3;1
o~c.
-I-
.3(0 H--O]
.;t'I4
"
,50
+
~
..
41';) +
as
·
4qi
J -
[.3,
74-:; +
3(,
..
Iflll{]
::
-
"8
J54
W
(')..rM
