Answer: A
This problem can be solved using the factor-label method:
.
..
gH O.
moles NaCl
mole NaCl
g NaCl
gH O
g NaCl
1000
10 0
1
58 50
1000
585
22
# =
The question is asking for the parts of NaCl per total solution (solute + solvent).
. g H O g NaCl
g NaCl
1000 585
585
2 +
- When 5.92 grams of a nonvolatile, nonionizing compound is dissolved in 186 grams of
water, the freezing point (at normal pressure) of the resulting solution is −0.592°C. What
is the molecular weight of the compound?
A. 10.0 g/mol
B. 100. g/mol
C. 110. g/mol
D. 200. g/mol
E. 210. g/mol
Answer: B
This problem can be solved using the factor-label method:
.
1..
0 592
186
1
592
186
1000
C 1
CkgHO
mole solute
g solute
gH O
gH O
kg H O
0.0100 mol/g 100. g/mol
2
2
2
2
# : ##==
%
%
- Calculate the number of grams of glycerol, C 3 H 5 (OH) 3 (MW = 92.1 g/mol), that must be
dissolved in 520. grams of water to raise the boiling point to 102.00°C.
A. 5.65 g
B. 92.0 g
C. 184 g
D. 194 g
E. 204 g
Answer: C
This problem can be solved using the factor-label method:
052. :
.. g.
1
520
1000
1 1
1
92 1
1
200
184
gH O
gH O
kg H O
CkgHO
mole C H OH
mole C H OH
CH OH C
gCH OH
2
2
2
2
3 5 3
3 5 3
3
35 3
35
####
=
%
^ %
^
^
^
h
h
h
h
Solutions