Worksheet: Solubility Graphs
Name______________
Use the provided solubility graph to answer the following questions:
For questions 1 – 4 an amount of solute is given,
and a temperature is stated. If all of the solute
could be dissolved in 100 g of water at the given
temperature, would the resulting solution be
unsaturated, saturated, or supersaturated?
1. 60 g KCl at 70 °C
_________
2. 10 g KClO3 at 60 °C
_________
3. 80 g NaNO3 at 10 °C _________
4. 70 g CaCl2 at 20 °C
_________
For questions 5 – 8 a solute and temperature are given. Tell how many grams of
each solute must be added to 100 g of water to form a saturated solution at the
given temperature.
5. Pb(NO3)2 at 10 °C
_________
7. NaCl at 20 °C
_________
6. Ce2(SO4)3 at 50 °C
_________
8. K2Cr2O7 at 50 °C
_________
For questions 9 and 10 underline the solution that is more concentrated.
9. At 10 °C: a saturated solution of KNO3 or a saturated solution of CaCl2.
10. At 50 °C: a saturated solution of KNO3 or an unsaturated solution of NaNO3
consisting of 90 g of the solute dissolved in 100 g of water.
For questions 11 – 12, show your work and circle your final answer.
11. If 115 g KNO3 are added to 100 g of water at 35 °C, how many grams do not
dissolve?
12. What mass of KCl would be needed to form a saturated solution if the KCl was
dissolved in 200 g of water at 80 °C?
CHEMISTRY: A Study of Matter
© 2004, GPB
10.12
Worksheet: More on Solubility
Name______________
1. Explain what is meant by the expression “like dissolves like”.
2. An unknown compound is observed to mix with benzene (a nonpolar solvent) but
not with water. Is the unknown compound ionic or covalent?
If the unknown compound is a liquid, will it be able to dissolve table
salt?____________ Explain:
3. What are the chemical characteristics of a good dry-cleaning solvent?
4. Explain why you are more likely to overdose on vitamin A than on vitamin C.
5. Some industrial plants use water from nearby rivers and streams as a coolant.
When the water is returned to the river or stream, the water is warmer than it
was originally. This is referred to as “thermal pollution”. Using your knowledge
of solubility, why might this thermal pollution be harmful to fish?
CHEMISTRY: A Study of Matter
© 2004, GPB
10.13
6. After a bottle of carbonated drink has been open for a while, it tastes “flat”.
Explain why.
7. For most solid solutes, the degree of solubility in a liquid solvent (increases,
decreases) with an increase in the temperature of the solvent.
8. Describe what happens to the degree of solubility of a gaseous solute in a liquid:
a) with a decrease in the temperature of the solvent.
b) with an increase in pressure ( ____________ Law).
9. The following statement is false: It is not possible to make a saturated solution
from a substance that is described as only slightly soluble. Explain why this
statement is false.
CHEMISTRY: A Study of Matter
© 2004, GPB
10.14
Lab: Solubility—Datasheet
Name______________
Procedure:
1) Each lab group was assigned a different temperature, calculating the solubility
of KCl in water at that temperature. Each group conducted the lab as seen on
the video, and their data follows. You are to complete columns #5 and #6,
using the provided data from each lab group.
Data:
#1
#2
#3
#4
Assigned
Mass of
Mass of
Mass of
Temperature evaporating evaporating evaporating
dish +
dish +
dish +

C
cover
cover +
cover +
KCl
dry KCl
solution
10
20
30
40
50
60
70
80
90
37.81 g
37.65 g
36.95 g
37.80 g
36.50 g
37.75 g
35.98 g
37.81 g
36.99 g
48.75 g
50.42 g
47.82 g
48.19 g
47.49 g
50.08 g
48.29 g
48.64 g
48.96 g
#5
Mass
of KCl
#6
Mass
of
water
(#4 - #2)
(#3 - #4)
#7
Mass of
KCl per
100 g of
water
40.54 g
40.99 g
39.81 g
40.63 g
39.75 g
41.52 g
39.86 g
41.37 g
40.98 g
2) Column #7 is to be calculated as to express the solubility of KCl in grams per
100 grams of water. Following the equation given, complete column #7 for each
group’
s data.
Mass of KCl
? g KCl = 100 g H2O 
=
Mass of water
CHEMISTRY: A Study of Matter
© 2004, GPB
10.10
3) Construct a graph using the vertical axis for grams of solute per 100 g of
solvent and the horizontal axis for temperature. Staple your graph to this
paper. BE SURE TO USE PROPER SCIENTIFIC GRAPHING TECHNIQUES.
Conclusion Questions:
1. The solubility of a solute is the maximum mass of the solute that will dissolve in
a certain amount of water at a certain ______________. This is the same as
saying that solubility is the concentration of a (unsaturated, saturated) solution
of the solute.
2. From your graph, what mass of KCl can be dissolved in 100 g of water at these
temperatures? Use dotted lines on your graph to show how you used your graph
to determine your answers:
a) 25 
C__________________ b) 55 
C____________________
3. For each of the following, tell whether the solution would be saturated,
unsaturated, or *crystallizing. (Hint: Plot the point and see whether it lies
above, below, or on the best-fit line. Remember that the line represents a
___________ solution.)
a) 40.0 g of KCl in 100 g of water at 75 
C
b) 34.0 g of KCl in 100 g of water at 55 
C
c) 45.0 g of KCl in 100 g of water at 25 
C
___________________
___________________
___________________
*Normally, crystallization (rather than supersaturation) occurs when more solute is
present than what can be dissolved in a given amount of solvent at a given
temperature. Crystallization simply refers to the excess solute “
crystallizing”and
settling out of the solution. Supersaturation is rare.
CHEMISTRY: A Study of Matter
© 2004, GPB
10.11