Download 1 Chem 250 2nd Semester Exam Review Worksheet Part II

Chem
250
2nd
Semester
Exam
Review
Worksheet
Part
II
(answers
are
at
the
end
of
this
worksheet)
1.
Carbon
dioxide
is
released
into
the
atmosphere
through
the
combustion
of
octane
(C8H18)
in
gasoline.
Write
the
balanced
chemical
equation
for
the
combustion
of
octane
and
calculate
the
mass
of
octane
needed
to
release
5.00
mol
CO2.
2.
Chloroform
(CHCl3),
and
important
solvent,
is
produced
by
a
reaction
between
methane
and
chlorine.
CH4(g)
+
3Cl2(g)

CHCl3(g)
+
3HCl(g)
How
many
g
CH4
is
needed
to
produce
50.0
g
CHCl3?
3.
An
alkaline
battery
produces
electrical
energy
according
to
this
equation.
Zn(s)
+
2MnO2(s)
+
H2O(l)

Zn(OH)2(s)
+
Mn2O3(s)
a)
Determine
the
limiting
reactant
if
25.0
g
Zn
and
30.0
g
MnO2
are
used.
b)
Determine
the
mass
of
Zn(OH)2
produced.
1
4.
Pure
zirconium
is
obtained
using
the
two‐step
Van
Arkel
process.
In
the
first
step,
impure
zirconium
and
iodine
are
heated
to
produce
zirconium
iodide
(ZrI4).
In
the
second
step,
ZrI4
is
decomposed
to
produce
pure
zirconium.
ZrI4(s)

Zr(s)
+
2I2(g)
Determine
the
percent
yield
of
zirconium
if
45.0
g
ZrI4
is
decomposed
and
5.00
g
pure
Zr
is
obtained.
5.
A
sealed
flask
contains
neon,
argon,
and
krypton
gas.
If
the
total
pressure
in
the
flask
is
3.782
atm,
the
partial
pressure
of
Ne
is
0.435
atm,
and
the
partial
pressure
of
Kr
is
1.613
atm,
what
is
the
partial
pressure
of
Ar
in
torr?
6.
Hot‐air
balloons
rise
because
the
hot
air
inside
the
balloon
is
less
dense
than
the
cooler
air
outside.
Calculate
the
volume
an
air
sample
will
occupy
inside
a
balloon
at
43.0
oC
if
it
occupies
2.50
L
at
the
outside
air
temperature
of
22.0
oC,
assuming
the
pressure
is
the
same
at
both
locations.
2
7.
A
sample
of
nitrogen
gas
is
stored
in
a
500.0
mL
flask
at
108
kPa
and
10.0
oC.
The
gas
is
transferred
to
a
750.0
mL
flask
at
21.0
oC.
What
is
the
pressure
of
nitrogen
in
the
second
flask?
8.
CO
is
a
product
of
incomplete
combustion
of
fuels.
Find
the
volume
that
42
g
of
CO
gas
occupies
at
STP.
9.
A
2.00
L
flask
is
filled
with
propane
gas
(C3H8)
at
1.00
atm
and
‐15.0
oC.
What
is
the
mass
of
the
propane
in
the
flask?
10.
When
heated,
solid
potassium
chlorate
(KClO3)
decomposes
to
form
solid
potassium
chloride
and
oxygen
gas.
If
20.8
g
of
potassium
chlorate
decomposes,
how
many
liters
of
oxygen
gas
will
form
at
STP?
3
11.
What
mass
of
water
must
be
added
to
255.0
g
NaCl
to
make
a
15.00
percent
by
mass
aqueous
solution?
12.
How
many
grams
KOH
are
contained
in
64.3
mL
0.0238
M
solution?
13.
How
many
mL
of
0.400
M
HBr
solution
can
be
made
from
50.0
mL
of
8.00
M
HBr
solution?
14.
Calculate
the
molality
of
a
solution
that
contains
15.7
g
NaCl
in
100.0
g
H2O.
15.
Calculate
the
freezing
point
and
boiling
point
of
2.75
m
NaOH
in
water.
4
16.
How
much
heat
is
absorbed
by
a
2000
kg
granite
boulder
as
energy
from
the
sun
causes
its
temperature
to
change
from
10oC
to
29oC?
17.
How
much
heat
is
evolved
when
1255
g
of
water
condenses
to
a
liquid
at
100oC?
18.
What
mass
of
octane
must
be
burned
in
order
to
liberate
5340
kJ
of
heat?
(ΔHcomb
=
‐5471
kJ/mol)
19.
NO
gas
and
Cl2
gas
react
according
to
the
equation
2NO
+
Cl2

2NOCl.
Use
the
following
data
to
determine
the
rate
law
for
the
reaction
by
the
method
of
initial
rates.
Also,
calculate
the
value
of
the
specific
rate
constant.
Initial
[NO]
Initial
Rate
(mol/L‐min)
Initial
[Cl2]
0.50
0.50
1.90
x
10‐2
1.00
0.50
7.60
x
10‐2
1.00
1.00
15.20
x
10‐2
5
20.
The
concentration
of
reactant
A
decreases
from
0.400
mol/L
at
time
=
0
to
0.384
mol/L
at
time
=
4.00
min.
Calculate
the
average
reaction
rate
during
this
time
period.
21.
Calculate
Keq
for
the
following
equilibrium
when
[SO3]
=
0.0160
M,
[SO2]
=
0.00560
M,
and
[O2]
=
0.00210
M.
heat
+
2SO3(g)

2SO2(g)
+
O2(g)
22.
Predict
the
shift
in
the
equilibrium
of
the
chemical
equation
in
#21
if:
a.
the
volume
increases
b.
the
pressure
increases
c.
[O2]
decreases
d.
[SO3]
increases
e.
the
temperature
decreases
Answers:
‐10.2
2.57
x
10‐4
4.00
x
10‐3
0.0859
17.1
34
71.4
73.0
74.8
102.8
16CO2
18H2O
k[NO]2[Cl2]
left
left
Units:
g
g
g
g
g
g
L2/(mol2
x
min)
m
mL
mol/(L
x
min)
0.152
112
MnO2
g
torr
6
1.734
2.68
1.00
x
103
25O2
right
kJ
kJ
oC
oC
2.69
1445
right
kPa
%
4.16
2830
right
L
5.70
30,000
6.72
2C8H18
L
L