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CHAPTER 16
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Text Reference: Section 16-15
Practice Problems
1~:~
A. mass of 48.5 g of a certain substance
can b~~dissolved in 29.1 em" 0
ate! at 20°C.
Calculate the solubility of this
sta.nce'::::..,,~..¢.~u
of water at the same temperature.
i/
l
-.t
.,
2. The solubility of a substance at a given
temperature is 0.368 g/100 g ~O. Calculate
e
number of grams of the substance
. dissolve, at the same temperature,'
-9 g of water.
3. The table below shows, e so
_ of
a certain substance per 100 g of water at various
temperatures.
mass of lithium chloride (LiCI)
. olved in 303 g of water to make a
'\\'hat
.?
~
so non.
mol; CI = 35.5 g/rnol)
8. 120 moles of a nonelectrolyte is dis~
so
~O g of wat~r. What ~sthe v~ue o~the ;{.
freezing pomt depression of this solution, given ~
that K: for water is 1.86°Clm?
9. 0.400 mole of a nonelectrolyte is dissolved in 2000.g of phenol. Calculate the freez~g J J.
point depress ion, given that K, for phenol lS~
.c__
L
0
23
.
--,-
4 'i.
7.4{)°Clm.
Temperature
b /,J lo.4
o
3
c,
z:
<is,\33
10. Calculate the freezing point depression \ I.
for a 0.877-m water solution of a nonelectrolyte,~
given that K, for water is 1.86°Clm.
.'
("C)
10
0.9
1.1
20
1.6
30
40
2.2
2.9
50
3.7
60
4.6
70
5.6
80
90
7.9
11. Calculate the molality of a solution of a
nonelectrolyte, given that the freezing point de- __
pression is 3.56°C and that K, for the solve
is
2.7TClm. Then calculate the mass of
e 1 re
dissolved in 8600 g of solven , gi en thaz - e moiar mass of the solute is 62.6 g/rnol.
12. A mass' of 78.1 g of a nonelectro .te - -'
has a molar mass of 60.3 g/mol is dissolve .
10.5 kg of chloroform. Calculate the boiling point
elevation, given that K; for chloroform .
6.7
1,2,
"C~
--
.r
3.63°C/m.
r:
~
a. Draw the solubility curve for this substance on a piece of graph paper. Make sure to
label your axes.
4 :l
lP \ ~
[P-i-,-13-D\-1]I.
,~
J.
b. What mass of the substance will dissolve
in 100 g of water at 75°C? What mass will dissolve
in IOcr g of water at 109°C?
ill
c. ~at mass of the substance will dissolve
325 g of water at 35°C?
4. Calculate the molarity of a solution,
~-=:~:-~=lgiven
that the solution has a volume of 8.80 dm?
~\and
contains 20.6 g of sodium hydroxide (NaOH).
(Na = 23.0 g/mol; 0
3
5.
=
16.0 g/mol; H = 1.0 g/mol)
What is the volume of a 1.44-M solution
sulfide (K2S) that contains 113.0 g
~71 ~rn <pfpotassium
~
MK2S?
(K
=
39.1 g/rnol; S
=
16-14
=
35.5 g/mol)
CHEMISTRY: The Study of Matter
0.52°Clm.
(C
= 12.0 g/mol; H = 1.0 g/mol; 0 ~ 16.0 g/rnol)
14. Calculate the mass of the nonelectrolyte
carbon tetrachloride (CCI4) dissolved in 298 g orrn
the solvent benzene, given that the molal boiling
point elevation constant (Kb) for benzene is
2.53°Clm, and that the boiling point elevation for
the solution is 7.45°C.
3
5:l'
0
_
j
U
12.0 g/mol; CI = 35.5 g/mol)
I. Cw
15. Calculate the molecular mass of a non'rrw\es
electrolyte, given that ..151 g of the substance de- It, ()w c.:cJ~lm
presses the freezing point of 3.500 k ..
@l:
n "lo v' rWtSS
2.53°C (Kr = 1.86°Clm).,
I
)Y,,,,(Jle.
16. The freezing point depressi
0 asolution of a nonelectrolyte in the solvent phenol is
9.21°C.Calculate the molecular mass of the sOlute'-'7-0-;)~}--'-/;--:-)
given that the solutioncont;:in~13:g
g of it dis- ~
lIP Imd
solved in 55.1 g ofphenol, whose Kr'is 7.40°Chn. ~ "\1[.\'\ i,5
(C
=
~7/M(J~ .""
32.1 g/rnol)
6. What is the molality of a solution made
by dissolving 22.7 g of sodium chloride (NaCI) in
3.18 x 103 g of water?
(Na = 23.0 g/mol; CI
13. Calculate the boiling point elevation of a
water solution of the nonelectrolyte glucose -------c"
(CsH1206),given that the solution contains 535 g of
J'glucose in 989 g of water, and that Kb for water is ~
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