Activity 5: Graphing Solubility Curves
1. Determine which of the variables should be on the x-axis (independent variable) and which goes on the y-axis (dependent variable). Remember that the independent variable is the one that we manipulate.
2. Plot the graphs for the following two compounds (use graph paper).
3. Title your graph and label the X and Y axis.
4. Add a legend key to identify the two different curves.
5. Answer the discussion questions.
|
Water temperature (celcius) |
mass of solute (grams) |
|
|
Water temperature (celcius) |
mass of solute (grams) |
|
0 |
23.1 |
|
|
0 |
89.5 |
|
10 |
27.5 |
|
|
10 |
68.4 |
|
20 |
32.0 |
|
|
20 |
52.9 |
|
30 |
37.8 |
|
|
30 |
41.0 |
|
40 |
44.6 |
|
|
40 |
31.6 |
|
50 |
53.2 |
|
|
50 |
23.5 |
|
60 |
61.8 |
|
|
60 |
16.8 |
|
70 |
72.8 |
|
|
70 |
11.1 |
|
80 |
83.8 |
|
|
80 |
6.5 |
|
90 |
98.9 |
|
|
90 |
3.0 |
|
100 |
114.0 |
|
|
100 |
0.0 |
The solubility data on the left is for Copper (II) Sulphate; the solubility data on the right is for Ammonia
(Note: data is for the amount of solute per 100 grams of water)
Discussion Questions:
1. What part of the curve represents the composition of a saturated solution? Unsaturated? Supersaturated?
2. Estimate the mass of Ammonia that can be dissolved in 100grams of water at 50C.
3. Which compound’s solubility varies directly with temperature? Which varies indirectly? Explain your choices.
4. In your own words, describe how the solubilities of gases change with temperature of the solvent; and how the solubilities of solids change with the temperature.