Chemistry, The Central Science, 10th edition

1
Chapter 13Properties of Solutions

• Chemistry, The Central Science, 10th edition
• Theodore L. Brown H. Eugene LeMay, Jr.
• and Bruce E. Bursten

Troy Wood University of Buffalo Buffalo, NY ?
2006, Prentice Hall
2
From weakest to strongest, rank the following
solutions in terms of solventsolute
interactions NaCl in water, butane (C4H10) in
benzene (C6H6), water in ethanol.

1. NaCl in water lt C4H10 in C6H6 lt water in ethanol
2. Water in ethanol lt NaCl in water lt C4H10 in C6H6
   
3. C4H10 in C6H6 lt water in ethanol lt NaCl in water

3
Correct Answer

1. NaCl in water lt C4H10 in C6H6 lt water in ethanol
2. Water in ethanol lt NaCl in water lt C4H10 in C6H6
   
3. C4H10 in C6H6 lt water in ethanol lt NaCl in water

Butane in benzene will have only weak dispersion
force interactions. Water in ethanol will
exhibit much stronger hydrogen-bonding
interactions. However, NaCl in water will show
iondipole interactions because NaCl will
dissolve into ions.
4
At a certain temperature, the Henrys law
constant for N2 is 6.0 ? 10?4 M/atm. If N2 is
present at 3.0 atm, what is the solubility of N2?

1. 6.0 ? 10?4 M
2. 1.8 ? 10?3 M
3. 2.0 ? 10?4 M
4. 5.0 ? 10?5 M

5
Correct Answer

1. 6.0 ? 10?4 M
2. 1.8 ? 10?3 M
3. 2.0 ? 10?4 M
4. 5.0 ? 10?5 M

Henrys law,
Sg (6.0 ? 10?4 M/atm)(3.0 atm) Sg 1.8 ? 10?3 M
6
Determine the mass percentage of hexane in a
solution containing 11 g of butane in 110 g of
hexane.

1. 9.0
2. 10.
3. 90.
4. 91

7
Correct Answer

1. 9.0
2. 10.
3. 90.
4. 91

solution

in
component

of

mass
?

100
component

of



mass
solution

of

mass

total
Thus, 110 g (110 g 11 g)
? 100 91
8
If 3.6 mg of Na is detected in a 200. g sample
of water from Lake Erie, what is its
concentration in ppm?

1. 7.2 ppm
2. 1.8 ppm
3. 18 ppm
4. 72 ppm

9
Correct Answer

1. 7.2 ppm
2. 1.8 ppm
3. 18 ppm
4. 72 ppm

solution

in
component

of

mass
?

6
10
component

of

ppm
solution

of

mass

total
g

0.0036
mg

3.6

?

6
ppm

18
10
g

200.
g

200.
10
What is the molality of 6.4 g of methanol (CH3OH)
dissolved in 50. moles of water?

1. 0.040 m
2. 0.22 m
3. 0.064 m
4. 0.11 m

11
Correct Answer

1. 0.040 m
2. 0.22 m
3. 0.064 m
4. 0.11 m

12

• How many moles of solute are there in 240 g of a
  solution that is 5.0 glucose (C6H12O6) by mass?

1. 0.033 moles
2. 0.067 moles
3. 0.10 moles
4. 0.12 moles
5. 0.20 moles

13
Correct Answer

1. 0.033 moles
2. 0.067 moles
3. 0.10 moles
4. 0.12 moles
5. 0.20 moles

5.0 glucose means 5.0 g glucose/100 g
solution (5.0 g glucose/100 g solution)(240 g
solution) 12 g (12 g glucose) ? (1 mol
glucose/180 g glucose) 0.067 moles glucose
14
At a certain temperature, water has a vapor
pressure of 90.0 torr. Calculate the vapor
pressure of a water solution containing 0.080
mole sucrose and 0.72 mole water.

1. 9.0 torr
2. 10. torr
3. 80. torr

1. 81. torr
2. 90. torr

15
Correct Answer

1. 9.0 torr
2. 10. torr
3. 80. torr
4. 81. torr
5. 90. torr

?

P
P
total
i
i
Pi XiPtotal Pi (0.72 mol/0.72 0.080
mol)(90.0 torr) Pi (0.90)(90.0 torr) 81. torr
16

• Ethanol normally boils at 78.4C. The boiling
  point elevation constant for ethanol is 1.22C/m.
  What is the boiling point of a 1.0 m solution of
  CaCl2 in ethanol?

1. 77.2C
2. 79.6C
3. 80.8C

1. 82.1C
2. 83.3C

17
Correct Answer

1. 77.2C
2. 79.6C
3. 80.8C
4. 82.1C
5. 83.3C

m
K
T
?
b
b
The increase in boiling point is determined by
the molality of total particles in the solution.
Thus, a 1.0 m solution of CaCl2 contains 1.0 m
Ca2 and 2.0 m Cl? for a total of 3.0 m. Thus,
the boiling point is elevated 3.7C, so it is
78.4C 3.7C 82.1C.
18

• At 300 K, the osmotic pressure of a solution is
  0.246 atm. What is its concentration of the
  solute?

1. 1.0 M
2. 0.50 M
3. 0.25 M
4. 0.10 M

19
Correct Answer
(
)

1. 1.0 M
2. 0.50 M
3. 0.25 M
4. 0.10 M

n


MRT
RT
?
V
M ? /RT M (0.246 atm)/(0.0821
L-atm/mol-K)(300K) M (0.246 atm)/(0.2463
L-atm/mol) 1.0 M
20

• Which of the following is not an example of a
  colloid?

1. Fog
2. Smoke
3. Paint
4. Milk
5. Carbonated water

21
Correct Answer

1. Fog
2. Smoke
3. Paint
4. Milk
5. Carbonated water

Carbonated water is a solution all the other
substances in the list are excellent examples of
colloids.