1. Chapter 12 Solutions 12.3 Solubility
Learning Goal Define solubility; distinguish between an unsaturated and a saturated solution. Identify a salt as soluble or insoluble.
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2. Solubility Solubility
is the maximum amount of solute that dissolves in a specific amount of solvent
can be expressed as grams of solute per 100 grams of solvent, usually water
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3. Saturated Solutions
Saturated Solutions
contain the maximum amount of solute that can dissolve
have undissolved solute at the bottom of the container
have equal rates at which the solute dissolves and crystallizes

4. Saturated, Unsaturated Solutions

5. Solubility and Temperature
depends on temperature
increases as temperature increases for most solids
decreases as temperature increases for gases
In water, most common solids are more soluble as the temperature increases.

6. Learning Check
At 40 C, the solubility of KBr is 80. g/100 g H2O. Identify the following solutions as either (S) saturated or (Un) unsaturated.
A g of KBr added to 100. g of water at 40 C
B g of KBr added to 200. g of water at 40 C
C. 25 g of KBr added to 50. g of water at 40 C

7. Solution
At 40 C, the solubility of KBr is 80. g/100 g H2O.
60. g of KBr added to 100. g of water at 40 C
Un, the amount of 60. g of KBr in 100. g of water, is less than the solubility of 80. g of KBr in 100. g of water.

8. Solution
At 40 C, the solubility of KBr is 80. g/100 g H2O.
200. g of KBr added to 200. g of water at 40 C
S, in 100. g of water, 100. g of KBr exceeds the solubility of 80. g of KBr water at 40 C.

9. Solution
At 40 C, the solubility of KBr is 80. g/100 g H2O.
C. 25 g of KBr added to 50. g of water at 40 C
Un, this is the same as 50. g of KBr in 100. g of water, which is less than the solubility of 80. g of KBr in 100 g of water at 40 C.

10. Solubility and Pressure
Henry’s law states that
the solubility of a gas in a liquid is directly related to the pressure of that gas above the liquid
at higher pressures, more gas molecules dissolve in the liquid

11. Solubility and Pressure, Henry’s Law
When the pressure of a gas above the solution decreases, the solubility of that gas in the solution also decreases.

12. Learning Check
Why could a bottle of carbonated drink possibly burst (explode) when it is left out in the hot sun?
Why do fish die in water that is too warm?

13. Solution
Why could a bottle of carbonated drink possibly burst (explode) when it is left out in the hot sun?
The pressure in a bottle increases as the gas leaves solution, because it becomes less soluble at high temperatures. As pressure increases, the bottle could burst.

14. Solution
B. Why do fish die in water that is too warm?
Because O2 gas is less soluble in warm water, fish cannot obtain the amount of O2 required for their survival.

15. Soluble, Insoluble
Ionic compounds that
dissolve in water are soluble salts
do not dissolve in water are insoluble salts

16. Solubility Rules
Soluble salts typically contain at least one ion from Groups 1A (1), NO3−, or C2H3O2− (acetate).

17. Using Solubility Rules
A barium sulfate-enhanced
X-ray of the abdomen
shows the large intestine.

18. Learning Check
Predict if the following compounds are soluble in water.
A. Li3PO4
B. PbSO4
C. Ca(NO3)2
D. AgCl

19. Solution
Predict if the following compounds are soluble in water.
A. Li3PO4 Soluble in water (Li+)
PbSO4 Not soluble in water
Ca(NO3)2 Soluble in water (NO3−)
D. AgCl Not soluble in water

20. Guide to Writing Equations for Insoluble Salt
A chemical equation shows the complete formulas of all the compounds in a reaction.
Pb(NO3)2(aq) + 2NaCl(aq)
PbCl2(s) + 2NaNO3(aq)

21. An ionic equation shows all the ionic compounds as separate ions.
Guide to Writing Equations for Insoluble Salt
An ionic equation shows all the ionic compounds as separate ions.
Pb2+(aq) + 2NO3−(aq) + 2Na+(aq) + 2Cl−(aq)
PbCl2(s) + 2Na+(aq) + 2NO3−(aq)
A net ionic equation shows only the ions that react to form a solid.
Pb2+(aq) + 2Cl−(aq) PbCl2(s)

22. Guide to Writing Equations for Insoluble Salt

23. Learning Check
When solutions of AgNO3 and NaCl are mixed, a white solid forms. Write the ionic and net ionic equations for the reaction.

24. Solution
When solutions of AgNO3 and NaCl are mixed, a white solid forms. Write the ionic and net ionic equations for the reaction.
Step 1 Write the ions of the reactants.
Ag+(aq) + NO3−(aq) + Na+(aq) + Cl−(aq)

25. Solution
When solutions of AgNO3 and NaCl are mixed, a white solid forms. Write the ionic and net ionic equations for the reaction.
Step 2 Write the combinations of ions and determine if any are insoluble.

26. Step 3 Write the ionic equation including any solid.
Solution
When solutions of AgNO3 and NaCl are mixed, a white solid forms. Write the ionic and net ionic equations for the reaction.
Step 3 Write the ionic equation including any solid.
Ag+(aq) + NO3−(aq) + Na+(aq) + Cl−(aq)
AgCl(s) + Na+(aq) + NO3−(aq)
Ionic equation

27. Solution
When solutions of AgNO3 and NaCl are mixed, a white solid forms. Write the ionic and net ionic equations for the reaction.
Step 4 Write the net ionic equation.

28. Ag+(aq) + Cl−(aq) AgCl(s)
Solution
Ag+(aq) + Cl−(aq) AgCl(s)
Net ionic equation