Chapter 9: Solutions:
1. Which of the following is heterogeneous, homogeneous, and a
colloid?
a. milk –colloid, you cannot filter milk
b. rocky road ice cream -heterogeneous
c. seawater -homogeneous
d. orange juice –heterogeneous…the pulp inside the orange
juice creates a mixture that is easily filtered.
2. Which of the following interactions causes acetic acid
(CH3COOH) to dissolve in water (H2O)?
a. Dipole-dipole forces
b. London dispersion forces
c. Hydrogen bonding
d. Covalent bonding
3. Which of the following are solutions? How can you tell? {Hint:
There is more than one answer.}
Solutions are homogeneous and the particle size is small.
a.
b.
c.
d.
Italian salad dressing- heterogeneous
Rubbing alcohol –homogeneous, very small
Algae in pond water -heterogeneous
Black coffee –homogeneous, small
a. Solution – homogeneous mixtures: particle size too small,
mixture too alike or pure.
b. Colloid –particle size extremely large
c. Heterogeneous mixture – usually are mixtures like
orange juice, paint, blood, rocky road ice cream
(melted) which have small particle sizes. The
contents can be separated.
7. T/F: The solute dissolves the solvent.
a. The solvent dissolves the solute.
8. What does “like dissolve like” mean?
a. Solvents tend to dissolve solutes with similar polarities. For
example, polar solvents dissolve polar solutes and nonpolar
solvents dissolve nonpolar solutes.
9. Identify which of the following substances is not a solid hydrate.
What property is associated with solid hydrates? From the
following substances, which solid hydrate would work better?
a. MgSO4 ∙7 H2O
b. CaSO4 ∙2 H2O
c. CuSO4 ∙5 H2O
d. NaCl (not a solid hydrate)
Solid Hydrates- are ionic compounds that have the ability to
4. T/F: As temperature increases solids become more soluble.
5. T/F: As temperature increases, gases become more soluble.
a. As temperature increases, we have a higher
probability of contributing to the gaseous state
because the particles are becoming more highly
disorganized.
6. Which of the following mixtures can be filtered?
attract water molecules strongly enough that they hold onto
water even when crystalline. MgSO4 would be the best
choice from the list above because for every molecule of
MgSO4 there are 7 molecules of H2O present.
10. T/F: Hygroscopic substances are used as drying agents because
they attract water so strongly that they can pull water vapor
from the air. An example is CaCl2 and MgCl2
Chapter 9: Solutions:
11. What is the difference between a saturated solution and a
supersaturated solution?
a. A saturated soln. is a soln. that has reached the maximum
amount dissolved solute at equilibrium. A supersaturated
soln. is a solution that contains even more solute than a
saturated solution, often formed at HIGHER temperatures.
12. What is the molarity of 0.5 moles of sodium chloride is dissolved
to make 0.05 liters of solution.
𝑀𝑜𝑙𝑒𝑠 𝑜𝑓 𝑆𝑜𝑙𝑢𝑡𝑒
0.5
𝑀𝑜𝑙𝑎𝑟𝑖𝑡𝑦 =
=
= 𝟏𝟎𝐌
𝐿𝑖𝑡𝑒𝑟𝑠 𝑜𝑓 𝑆𝑜𝑙𝑛.
0.05
13. 0.5 grams of sodium chloride is dissolved to make 0.05 liters of
solution. Find the Molarity of NaCl.
0.5 𝑔 𝑁𝑎𝐶𝑙 ×
𝑀𝑜𝑙𝑎𝑟𝑖𝑡𝑦 =
1 𝑚𝑜𝑙 𝑁𝑎𝐶𝑙
= 0.00855 𝑚𝑜𝑙 𝑁𝑎𝑐𝑙
58.44 𝑔 𝑜𝑓 𝑁𝑎𝐶𝑙
0.00855 𝑚𝑜𝑙 𝑜𝑓 𝑁𝑎𝐶𝑙
= 𝟎. 𝟏𝟕𝐌
0.05 𝐿 𝑜𝑓 𝑠𝑜𝑙𝑛.
14. 734 grams of lithium sulfate Li2SO4 are dissolved to make 2500
mL of solution.
1 𝑚𝑜𝑙
734 𝑔 𝑜𝑓 𝐿𝑖2 𝑆𝑂4 ×
= 6.68 𝑚𝑜𝑙
109.94 𝑔
1𝑙
2500 𝑚𝑙 ×
= 2.5 𝐿
1000 𝑚𝑙
6.68
𝑀𝑜𝑙𝑎𝑟𝑖𝑡𝑦 =
= 𝟐. 𝟔𝟕 𝑴
2.5
15. If I make a solution by adding water to 35 mL of methanol
(CH3OH) until the final volume of the solution is 275 mL…
a. What is the molarity of methanol in this solution? (The
density of methanol is 0.792 g/mL)
𝐷=
𝑀
𝑉
0.792
𝑔
𝑚
=
= 27.72 𝑔 𝑜𝑓 𝑀𝑒𝑡ℎ𝑎𝑛𝑜𝑙
𝑚𝑙 35 𝑚𝑙
When solving this problem, you’ll need to calculate that
there are 27.72 grams of methanol (from the density):
27.72 𝑔 𝑜𝑓 𝑀𝑒𝑡ℎ𝑎𝑛𝑜𝑙 ×
1 𝑚𝑜𝑙𝑒 𝑜𝑓 𝑀𝑒𝑡ℎ𝑎𝑛𝑜𝑙
32.04 𝑔 𝑜𝑓 𝑀𝑒𝑡ℎ𝑎𝑛𝑜𝑙
= 0.866 𝑚𝑜𝑙 𝑜𝑓 𝑀𝑒𝑡ℎ𝑎𝑛𝑜𝑙
𝑀𝑜𝑙𝑎𝑟𝑖𝑡𝑦 =
0.866 𝑚𝑜𝑙
= 𝟑. 𝟏𝟓 𝑴
0.275 𝐿
b. What is the percent by volume of methanol in this solution?
𝟏𝟐. 𝟕% =
𝑣
35 𝑚𝑙
= [(
) × 100]
𝑣
275 𝑚𝑙
16. If I add 25 mL of water to 125 mL of a 0.15 M NaOH solution,
what will the molarity of the diluted solution be?
M1V1 = M2V2
(0.15 M)(125 mL) = x (150 mL)
x = 0.125 M
17. How much 0.05 M HCl solution can be made by diluting 250 mL
of 10 M HCl?
M1V1 = M2V2
(10 M)(250 mL) = (0.05 M) x
x = 50,000 mL
Chapter 9: Solutions:
18. I wanted to add 100 mL of 18 M H2SO4 to my drain to clean it,
but instead I spilled it on the floor. How much baking soda
(NaHCO3) do I need to pour on it to neutralize it?
H2SO4 + 2 NaHCO3
Na2SO4 + 2 H2CO3
Molarity x liters of solution = mol of solute
0.10 L H2SO4 x 18 mol/L = 1.8 mol H2SO4
1.8 mol H2SO4 x 2 mol NaHCO3/ 1 mol H2SO4 = 3.6 mol NaHCO3
(mol to mol ratio)
3.6 mol NaHCO3 x 84 g / 1 mol NaHCO3 = 300 g NaHCO3
19. If the solubility of CO2 in water at 20°C and 760 mm Hg is 0.169
g/100 mL, what is its solubility at 20°C and 1.50 atm?
𝐶1
𝑃1
𝐶2
= 𝑃2
(0.169 𝑔/100 𝑚𝐿)
𝐶2
=
760 𝑚𝑚 𝐻𝑔
1140 𝑚𝑚 𝐻𝑔
C2 = 0.254 g/100 mL = 2.54 x 10-3 g/mL
20. Which of the following is not an electrolyte?
a. Gasoline – does not conduct electricity when
dissolved in water.
b. NaCl (aq)
c. MgBr (aq)
21. T/F: Osmosis is the passage of a solvent through a
semipermeable membrane (separates two solutions of different
concentrations) like the phospholipid bilayer.
22. A cell that is hypotonic _____ in comparison to its external
environment.
a. Has too much water
b. Has equal amounts of water
c. Has not enough water
23. A cell that leaves an isotonic environment suddenly becomes
hypertonic causing it to shrivel. An explanation for cell death is
because:
a. The cell was once normal and then lost too much
water
b. The cell gained too much water after leaving its normal
environment
c. External factors contributing to the lysing of the cell