Unit 9 Question Packet
Solutions
Name ………………………………………………
Period ………….
SKILLS
1. Identifying SOLUTE AND SOLVENT
2. Identifying SOLUBLE AND INSOLUBLE COMPOUNDS
3. Writing and Balancing Equations for DOUBLE
REPLACEMENT REACTIONS
SKILL #1:
4.
5.
6.
7.
Understanding FACTORS THAT AFFECT SOLUBILITY
Determining TYPE OF SOLUTION USING TABLE G
Expressing Concentration in MOLARITY OR PPM
Identifying PROPERTIES OF SOLUTIONS
Identifying SOLUTE AND SOLVENT
1. Fill in the table below.
Solution
Solute Name
Formula
magnesium
MgBr2(aq)
bromide
potassium sulfate
K2SO4(aq)
FeCl3(aq)
iron (III) chloride
coppper (II) sulfate
CuSO4(aq)
- refer to your notes & RB p. 99-100
Solvent
Formula
Solution Name
Solute Formula
H2O
aqueous potassium nitrate
KNO3
H2O
aqueous sodium acetate
NaC2H3O2
H2O
aqueous ammonium
hydroxide
NH4OH
H2O
aqueous lithium bromide
LiBr
BaNO3(aq)
barium nitrate
H2O
aqueous magnesium
hypochlorite
Mg(ClO)2
(NH4)2CO3(aq)
ammonium
carbonate
H2O
aqueous iron (II) nitrate
Fe(NO3)2
SKILL #2:
identifying SOLUBLE AND INSOLUBLE COMPOUNDS
- refer to your notes and RB p. 103
2. Use Table F to determine if the following compounds are soluble or insoluble.
SKILL #3:
3.
a. NaCl soluble
e. K3PO4 soluble
i. calcium hydroxide
soluble
b. PbBr2 insoluble
f. MgCO3 insoluble
j. copper (II) hydroxide
insoluble
c. CaSO4 insoluble
g. NH4NO3 soluble
k. lead(II) sulfate
insoluble
d. potassium chromate
soluble
h. sodium hydrogen
carbonate soluble
l. ammonium sulfide
soluble
Writing and Balancing Equations for DOUBLE REPLACEMENT REACTIONS
Write the balanced chemical equation for each of the following descriptions.
 Use Table F to determine the state of the products – (s) or (aq).
 Write “soluble” or “insoluble” under each reactant and product.
 Square off the precipitate.
(a) Solutions of sodium carbonate and silver nitrate are mixed.
Na2CO3 (aq) + 2 AgNO3 (aq)  Ag2CO3(s) + 2 NaNO3 (aq)
soluble
soluble
insoluble
soluble
(b) AgC2H3O2 (aq) is mixed with NaCl (aq).
AgC2H3O2 (aq) +NaCl (aq)  AgCl (s) + NaC2H3O2 (aq)
- refer to your notes
soluble
soluble
insoluble
soluble
(c) Solutions of potassium sulfate and calcium chlorate are mixed.
K2SO4 (aq) + Ca(ClO3)2 (aq)  2 KClO3 (aq) + CaSO4 (s)
soluble
soluble
soluble
insoluble
(d) CaCl2 (aq) and Na2S (aq) are mixed.
CaCl2 (aq) + Na2S (aq)  CaS (s) + 2 NaCl (aq)
soluble
soluble
insoluble soluble
(e) What do all the above double replacement reactions have in common?
They start with two compounds and end with two compounds
SKILL #4:
Understanding FACTORS THAT AFFECT SOLUBILITY
- refer to your notes & RB p. 102
4. Check the conditions under which each of the following solutes will be most soluble. Look at Table G
for help.
Solute Name
Solute
Formula
Temperature
Low
High

Low
Pressure
High
No
Effect

Best Solvent
H2O
CCl4

potassium nitrate
KNO3(s)
hydrochloric acid
HCl(g)



ammonia
NH3(g)



ammonium chloride
carbon dioxide
CO2(g)





KI(s)



KClO3(s)



potassium iodide
potassium chlorate

NH4Cl(s)
5. Naphthalene, a nonpolar substance that sublimes at room temperature, can be used to protect wool clothing
from being eaten by moths.
a. Explain, in terms of intermolecular forces, why naphthalene sublimes. [1]
b. Explain why naphthalene is not expected to dissolve in water. [1]
c. The empirical formula for naphthalene is C5H4 and the molecular mass of naphthalene is 128
grams/mole. What is the molecular formula for naphthalene? [1]
a.
Naphthalene has weak intermolecular forces
b. Naphthalene is nonpolar; water is polar.
Nonpolar won’t dissolve in polar.
Like dissolves like.
c.
C10H8
or H8C10
SKILL #5:
Determining TYPE OF SOLUTION USING TABLE G
- refer to your notes & RB p.104-107
6. State whether each of the following solutions is saturated, unsaturated, or supersaturated.
(a) 80 g NaNO3 in 100 g H2O at 10ºC
___________________________saturated
(b) 75 g NaNO3 in 100 g H2O at 10ºC
___________________________unsaturated
(c) 90 g NaNO3 in 100 g H2O at 10ºC
___________________________supersaturated
(d) 90 g KNO3 in 100 g H2O at 50ºC
___________________________supersaturated
(e) 90 g KI in 100 g H2O at 50ºC
___________________________unsaturated
(f) 5 g KClO3 in 100 g H2O at 5ºC
___________________________saturated
(g) 40 g KCl in 50 g H2O at 60ºC
___________________________supersaturated
(h) 35 g NaNO3 in 50 g H2O at 10ºC
___________________________unsaturated
(i) 5 g KClO3 in 50 g H2O at 5ºC
___________________________supersaturated
(j) 5 g KClO3 in 200 g H2O at 5ºC
___________________________unsaturated
(k) 30 g NH4Cl in 200 g H2O at 10ºC
___________________________unsaturated
(l) 40 g SO2 in 200 g H2O at 5ºC
___________________________saturated
7. Tell how many MORE grams of each solute must be added to 100 g of water to form a saturated
solution at that temperature.
Grams Solute
per
100 g H2O
a. 35 g KNO3 at
40ºC
b. 50 g NH3 at
10ºC
c. 15 g KCl at
75ºC
d. 95 g KI at
15ºC
Solute
Added to
make
Saturated
30 g
Grams Solute
per
200 g H2O
e. 70 g NaCl
at 90ºC
f. 10 g NH3 at
90ºC
g. 20 g KClO3
at 40ºC
h. 35 g KCl at
60ºC
20 g
35 g
45 g
Solute
Added to
make
Saturated
10 g
10 g
12 g
55 g
Grams Solute
per
200 g H2O
i. 25 g NH3 at
5ºC
j. 30 g NaNO3
at 50ºC
k. 15 g KClO3
at 75ºC
l. 5 g KCl at
75ºC
Solute
Added to
make
Saturated
15 g
27.5 g
5g
20 g
8. Tell how many grams of each solute will crystallize/precipitate/settle. Assume all solutions are
saturated and in 100 grams of H2O.
Amount cooled
a. KNO3 (aq) is cooled
from 70ºC to 40ºC
b. NH4Cl (aq) is cooled
from 90ºC to 20ºC
c. KCl (aq) is cooled
from 55ºC to 30ºC
d. KI (aq) is cooled
from 20ºC to 5ºC
Amount
Precipitated
70 g
34 g
9g
14 g
Amount cooled
e. NaCl (aq) is cooled
from 100ºC to 40ºC
f. KNO3 (aq) is cooled
from 65ºC to 25ºC
g. KClO3 (aq) is cooled
from 100ºC to 40ºC
h. NaNO3 (aq) is cooled
from 45ºC to 10ºC
Amount
Precipitated
2g
80 g
45 g
30 g
9. Rank the following solids in order from least to most soluble in 100 g H2O at 50ºC :
NH4Cl, NaNO3, KClO3, KNO3
KClO3, NH4Cl, KNO3, NaNO3
10. Rank the following gases in order from least to most soluble in 100 g H 2O at 50ºC :
NH3, SO2, HCl
SO2, NH3, HCl
SKILL #6:
Expressing Concentration in MOLARITY OR PPM
11. Calculate the molarity of each of the following solutions:
- refer to your notes & RB p.108
(a) 2.5 mol of NaOH in 0.500 L of solution
(b) 1.8L of solution containing 3.3 mol KNO 3
M = 2.5/0.5 = 5.0 M
M = 3.3/1.8 = 1.8 M
(c) 30. g of NaOH in 0.500 L of solution
mol = 30./40 = 0.75 mol
M = 0.75/0.5 = 1.5 M
(e) 12 g of HCl in 250 mL of solution
mol = 12/36 = 0.33 mol
(d) 522 g of K2SO4 in 1.5 L of solution
mol = 522/176 = 2.97 mol
M = 2.97/1.5 = 1.98 M
M = 0.33/0.25 = 1.3 M
12. Calculate the total moles of solute in each of the following solutions:
(a) 1.7 L of 0.35M NaOH
0.35 = X/1.7 = 0.595 mol
(b) 50 mL of 3.3-molar KNO3
3.3 = X/0.050 = 0.165 mol
(c) 5.0 L of 1.25 M NaOH
1.25 = X/5.0 = 6.25 mol
(d) 116 mL of 1.5 M K2SO4
1.5 = X/0.116 = 0.174 mol
13. Calculate the total grams of solute in each of the following solutions:
(a) 1.0 L of 0.5 M CaCl2
0.5 = X/1.0 = 0.5 mol
0.5 = X/110 = 55 g CaCl2
(b) 500 mL of 3.3-molar KNO3
3.3 = X/0.5 = 1.65 mol
1.65 = X/101= 167 g KNO3
(c) 0.25 L of 1.0 M NaOH
1.0 = X/0.25 = 0.25 mol
0.25 = X/40= 10 g NaOH
(d) 42 mL of 1.7 M K2SO4
1.7 = X/0.042 = 0.0714 mol
0.0714 = X/174 = 12.4 g K2SO4
14. Calculate the concentration of chlorine in a swimming pool if there is 0.02 g of chlorine in 10,000 g of
pool water.
ppm = (0.02/10,000) * 1,000,000 = 2 ppm
15. The health of fish depends on the amount of oxygen dissolved in the water. A dissolved oxygen (DO)
concentration between 6 parts per million and 8 parts per million is best for fish health. A DO
concentration greater than 1 part per million is necessary for fish survival. Fish health is also affected
by water temperature and concentrations of dissolved ammonia, hydrogen sulfide, chloride
compounds, and nitrate compounds.
A student’s fish tank contains fish, green plants, and 3800 grams of fish-tank water with 2.7 x 10-2 gram
of dissolved oxygen.
a.) State how an increase in the temperature of the fish-tank water affects the solubility of oxygen in
the water.
increasing the temperature Decreases the solubility of oxygen gas
b.) Determine if the DO concentration in the fish tank is healthy for fish. Your response must include:
• a correct numerical setup to calculate the DO concentration in the water in parts per million
• the calculated result
• a statement using your calculated result that tells why the DO concentration in the water is or is
not healthy for fish
ppm = (2.7 x 10-2/3800) * 1 000 000 = 7ppm
This is healthy for fish because it is greater than 1 ppm
16. Exposure to lead has been linked to delays in physical and mental development and attention deficit
disorders in children as well as kidney problems in adults. One source of this toxic heavy metal is
drinking water in older homes whose plumbing contains lead. Water with a lead concentration of
below 0.015ppm is considered safe to drink. A 100 g water sample taken from a home contains 1.2 x
10-6 grams of lead. Is this water considered safe to drink?
ppm = (1.2 x 10-6/100) *1 000 000 = 0.012 ppm
yes, it is safe to drink because it’s below 0.015 ppm
17.
A safe level of fluoride ions is added to many public drinking water supplies. Fluoride ions have been
found to help prevent tooth decay. Another common source of fluoride ions is toothpaste. One of the
fluoride compounds used in toothpaste is tin(II) fluoride.
A town located downstream from a chemical plant was concerned about fluoride ions from the plant
leaking into its drinking water. According to the Environmental Protection Agency, the fluoride ion
concentration in drinking water cannot exceed 4 ppm. The town hired a chemist to analyze its water.
The chemist determined that a 175-gram sample of the town’s water contains 0.000 250 gram of
fluoride ions.
a.
b.
c.
d.
Draw a Lewis electron-dot diagram for a fluoride ion.
What is the chemical formula for tin(II) fluoride? SnF2
How many parts per million of fluoride ions are present in the analyzed sample? 1.43
Is the town’s drinking water safe to drink? Support your decision using information in the passage and
your calculated fluoride level in question c. Safe: 1.43 ppm 4 ppm
18. Scientists who study aquatic ecosystems are often interested in the concentration of dissolved oxygen
in water. Oxygen, O2, has a very low solubility in water, and therefore its solubility is usually expressed
in units of milligrams per 1000. grams of water at 1.0 atmosphere. The graph below shows a solubility
curve of oxygen in water.
a.) A student determines that 8.2 milligrams of oxygen is dissolved in a 1000.-gram sample of water at
15°C and 1.0 atmosphere. In terms of saturation, what type of solution is this sample? unsaturated
b.) Explain, in terms of molecular polarity, why oxygen gas has low solubility in water. Your response
must include both oxygen and water.
Oxygen has low solubility in water because oxygen is nonpolar and water is polar.
c.) Under what kind of conditions of temperature and pressure would oxygen gas be most soluble in
water?
Low temperature and high pressure
d.) An aqueous solution has a concentration of 7 ppm of oxygen dissolved in 1000. grams of water.
Calculate the amount of oxygen in the solution in grams. Your response must include both a
correct numerical setup and the calculated result.
7 = (X/1000) *1000000
X = 0.007 g O2
SKILL # 7:
Identifying PROPERTIES OF SOLUTIONS
- refer to your notes & RB p.110
19. Compared to pure water, an aqueous solution of calcium chloride has a
(1) higher boiling point and higher freezing point
(2) higher boiling point and lower freezing point
(3) lower boiling point and higher freezing point
(4) lower boiling point and lower freezing point
20. Which solution has the highest boiling point?
1.0 M KNO3
(2) 2.0 M KNO3
21. Which solution has the lowest freezing point?
(1) 10. g of KI dissolved in 100. g of water
(2) 30. g of KI dissolved in 100. g of water
(3) 1.0 M Ca(NO3)2
(4) 2.0 M Ca(NO3)2
(3) 20. g of KI dissolved in 200. g of water
(4) 40. g of KI dissolved in 200. g of water
22. As water is added to a 0.10 M NaCl aqueous solution, the conductivity of the resulting solution
(1) decreases because the concentration of ions decreases
(2) decreases, but the concentration of ions remains the same
(3) increases because the concentration of ions decreases
(4) increases, but the concentration of ions remains the same
23. Which aqueous solution of KI freezes at the lowest temperature?
(1) 1 mol of KI in 500. g of water
(3) 1 mol of KI in 1000. g of water
(2) 2 mol of KI in 500. g of water
(4) 2 mol of KI in 1000. g of water
24. Compared to a 2.0 M aqueous solution of NaCl at 1 atmosphere, a 3.0 M aqueous solution of NaCl at
1 atmosphere has a
(1) lower boiling point and a higher freezing point
(2) lower boiling point and a lower freezing point
(3) higher boiling point and a higher freezing point
(4) higher boiling point and a lower freezing point
25. Based on Reference Table F, which of these saturated solutions has the lowest concentration
ofdissolved ions?
(1) NaCl(aq)
(2) MgCl2(aq)
(3) NiCl2(aq)
(4) AgCl(aq)
26. Compared to a 0.1 M aqueous solution of NaCl, a 0.8 M aqueous solution of NaCl has a
(1) higher boiling point and a higher freezing point
(2) higher boiling point and a lower freezing point
(3) lower boiling point and a higher freezing point
(4) lower boiling point and a lower freezing point