Standards:
 3.1.10 C Apply patterns as repeated processes or recurring elements in science and
technology.
 3.1.10 E Describe patterns of change in nature, physical and manmade systems.
 3.4.10 A Explain concepts about the structure and properties of matter.
Study the solubility curves in the figure, and
answer the questions that follow.
1. What relationship exists between
solubility and temperature for most
of the substances shown?
much KClO3 could be recovered by
evaporating the solution to dryness?
7. Five hundred grams of water are used
to make a saturated solution of KCl at
10oC. How many more grams of KCl
could be dissolved if the temperature
were raised to 100oC?
2. a. What is the exception?
b. What general principle accounts
for this exception?
8. A saturated solution of KNO3 in 200 g
of H2O at 50oC is cooled to 20oC. How
much KNO3 will precipitate out of
solution?
3. a. Approximately how many grams of
NaNO3 will dissolve in 100 g of
water at 20oC?
b. How many grams will dissolve at
60oC?
4. How many grams of NH4Cl will dissolve
in 1 liter of H2O at 50oC?
5. Ninety grams of NaNO3 is added to
100 g of H2O at 0oC. With constant
stirring, to what temperature must
the solution be raised to produce a
saturated solution with no solid
NaNO3 remaining?
6. A saturated solution of KClO3 was
made with 300 g of H2O at 40oC. How
1
Solubility Curves … Part II
1.
7. At what temperature do KBr and KNO3 have the same
solubility? What is that solubility?
Temperature:
Solubility:
What is plotted on …
8. At what temperature does NaClO3 have a solubility of
180 g/100 g H2O?
The X axis:
The Y axis:
2. In general what does the graph illustrate?
9. At what temperature does KNO3 have a solubility of 45
g/100 g H2O?
3. How would you describe what happens to the solubilities
of these substances as temperature increases?
10. What general statement can you make about the
solubility of NaCl with increasing temperature compared
with those of KBr, KClO3, and NaClO3?
4. What is the solubility of each of the four materials at
0oC?
a.
NaClO3
b. KBr
c.
KNO3
d. NaCl
5. Which substance is most soluble and which is least
soluble at 0oC?
Most:
Least:
6. At 80oC, which substance is most soluble and which is
least soluble?
Most:
Least:
2
Solubilities of Two Compounds
5. Calculate the molarity of a saturated solution
of substance A at 20oC. (Assume for simplicity
that the solubility per 100 g of water is
equivalent to the solubility per 100 mL of
solution.)
1. The diagram to the right shows how the
solubilities of two compounds, A and B, change
with temperature. One of the substances is
lead (II) chloride (PbCl2) and the other is
carbon dioxide (CO2). Which curve do you think
belongs to each substance?
A=
6. Calculate the molarity of a saturated solution
of substance B at 20oC.
B=
2. What is the basis for your answer to the above
question?
3. What are the solubilities of A and B at 0oC?
A=
B=
4. What are the solubilities of A and B at 20oC?
A=
B=
3
Stock Solutions
A group of students made a number of solutions of known concentrations for the class stockroom. Unfortunately,
they neglected to record all the information regarding the way in which the solutions were made. From the
information provided in the chart below, determine the ten missing values and write them on the lines.
Solute
formula
Solute Mass
Solution
Volume
KOH
7.80 g
500. mL
LiCl
______
CaCl2
9.00 g
Al2(SO4)3
12.3 g
K3PO4
______
4.00 L
250. mL
______
250. mL
Molarity
______
0.125 M
Solute
formula
Solute Mass
KClO3
122.5 g
NH4Br
HNO3
______
0.900 M
HCl
0.324 M
(NH4)2SO4
4
______
20.0 g
______
44.2 g
Solution
Volume
______
2.00 L
500. mL
750. mL
600. mL
Molarity
1.00 M
0.50 M
______
0.044 M
______