Solubility Curves
1. Which substance does not appear to
increase greatly in solubility as the
temperature is increased?
2. Which substance appears to decrease in
solubility as the temperature is
increased?
Reading a solubility chart
1.
2.
3.
4.
3. Which substance is the most soluble at
0C ?
4. Which substance is the least soluble at
0C ?
5.
5. Which two substances have the same
solubility at 71C ?
6.
6. What is the most KNO3 that can be
dissolved in 100 ml of water at 70C ?
7.
The curve shows the # of grams of solute in a saturated
solution containing 100 mL or 100 g of water at a certain
temperature.
Any amount of solute below the line indicates the solution is
unsaturated at a certain temperature.
Any amount of solute above the line in which all of the solute
has dissolved shows the solution is supersaturated.
If the amount of solute is above the line, but has not all
dissolved, the solution is saturated and the # grams of solute
settled on the bottom of the container = total # grams in
solution - # g of a saturated solution at that temperature.
(according to the curve)
Solutes whose curves move upward with increasing
temperatures are typically solids because the solubility of a
solid increases with increased temperature.
Solutes whose curves move downwards with increased
temperature are typically gases because the solubility of
gases decreases with increased temperature.
Use a proportion when the water given is larger or smaller
than 100 mL or 100 g
7. What is the most NH3 that can be dissolved in 100 ml of water at 70C ?
8. At 70C which substance, KNO3 or NH3, can form the more concentrated solution?
9. At what temperature would you need 100 ml of water to dissolve 100g NaNO3 ?
10. If 100ml of a saturated solution of NH4Cl at 100C is cooled to 20C, how much precipitate will form?
11. If 100 ml of a saturated solution of KNO3 at 50C is cooled to 10C, how much precipitate will form?
12. 200 ml of a solution contains 10g of KClO3 at 15C. The solution is then warmed to 100C. How much
additional KClO3 may be dissolved?
13. How many grams of NaNO3 are required to saturate 200ml of water at 10ºC?
14. A 100ml solution contains 35g KClO3 and 40g of NH4Cl at 80C. As the solution is cooled, which will
precipitate first?
15. Classify the following solutions as either: saturated, unsaturated or supersaturated (assume that all three
could form supersaturated solutions)
a) 40. g of KCl in 100 mL of water at 80oC
b) 120. g of KNO3 in 100 mL of water at 60oC
c) 80. g of NaNO3 in 100 mL of water at 10oC
SOLUBILITY CURVES FOR A NUMBER OF WATER
SOLUBLE INORGANIC SUBSTANCES