1. Solubility Rules & Reference Tables

2. Components of a Solution
Solute: substance being dissolved
Ex: Salt, Sugar
Solvent: substance doing the dissolving
Ex: Water, Hexane

3. What Dissolves in What? Solute must form attractions to the solvent.
Polars dissolve polars
Nonpolars dissolve nonpolars
Polar solvents dissolve most ionic crystals

4. Solubility: How much solute can be dissolved in a
volume of solvent under
certain conditions of
temp. and pressure.

5. Using Reference Table G
Shows solubility in grams of solute per 100 grams of water at different temperatures

6. Saturated Solutions: hold max solute
possible at that temp.
Table G:
Solubility curves show saturation levels at
different temps (in 100g of water).

7. Saturated Solutions are at EQUILIBRIUM.
Rate of dissolving = Rate of crystallization

8. Go to 50 °C and up to NaNO3 and over.
Ex: How many grams of NaNO3 are needed to create a sat. solution in 100g of water at 50 °C?
Go to 50 °C and up to NaNO3 and over.
Answer: 116 grams

9. Look at The Water!! Table G is for 100 grams of water.
Amount of water in your problem may be different and you need to adjust you answer.

10. How many grams of NaNO3 are needed to
create a sat. solution in 300g of water at 50 °C?
Answer: 116 grams x 3 (three times as much water!)
Or you can use a proportion:
116 grams = x grams
100 g H g H20

11. Unsaturated Solutions: could still hold
more solute at that temp.
Would fall “below the line” on Table G
Ex: 40 g of NaNO3 in 100g water at 50°

12. Supersaturated Solutions: hold more
solute than they should at that temp.
Would fall “above the line” on Table G
Ex: 140 g of NaNO3 in 100g water at 50°

13. How do Supersaturated Solutions Form?
Created a saturated solution at a high temp. and slowly let solution cool.
Certain solutes can stay in solution (like sodium acetate).

14. solutions are unstable. Add just one more “seed crystal” to the
Supersaturated
solutions are unstable.
Add just one more
“seed crystal” to the
solution, all the excess
solute will precipitate
out quickly.
Supersaturated Sodium Acetate solution after seed crystal added

15. Describe These Solutions
Saturated, Unsaturated or Supersaturated?
100 g NH4Cl at 70° in 100 g water
10 g SO2 at 10° in 100 g water
40 g NaCl at 90° in 100 g water

16. 100 g NH4Cl at 70° in
100 g water
Falls above the line (Supersaturated)

17. 10g SO2 at 10° in 100g
water
Falls below the line (Unsaturated)

18. 40g NaCl at 90° in 100g
water
Falls on the line (Saturated)

19. Concentrated Solutions:
have a lot of solute
dissolved in the solvent
Ex: Saturated solution of KI
at 10°
135 grams in 100 g water = pretty concentrated

20. Dilute Solutions: only
have a little solute
dissolved.
Ex: Sat. solution of SO2 at 50°
4 grams in 100 g water = relatively dilute

21. Factors Affecting Solubility

22. Surface Area
More contact between
solute/solvent particles
the faster it dissolves
Crush substance into fine
powder to dissolve faster.
Use mortar and pestle

23. Stirring or Agitation:
Allows for more solute/solvent
contact, and faster dissolving of
solids and liquids
However, stirring will disturb
dissolved gases and cause
them to come out of solution.

24. Temperature of Solvent
Higher temperature solvents will
dissolve solid solutes faster
Why?
Solvent particles move faster
making contact faster with solute.

25. Gases dissolve better when the temperature of the solvent is colder.
Ex: CO2 gas in hot soda (flat) vs. cold soda (fizzy)

26. Fish in aquariums need
the dissolved oxygen in
the water, if the temp
gets too high they
suffocate

27. Pressure
Effects gas solubility
only
Why?
Increasing pressure on
a gas above a liquid
causes more gas
molecules to be
“pushed” into solution.

28. Amount of Solute already Dissolved
The more particles already in solution the
less solvent molecules available to dissolve
new solute.

29. Miscible:
liquids that dissolve in any proportions (ex: alcohol and water)
Immiscible:
liquids that do not dissolve in any proportion (ex: oil and water)

30. Electrolytes:
Conduct electricity when dissolved in water

31. Why do they Conduct? Create mobile ions in solution.
The more concentrated the solution the more it conducts
Includes:
Soluble Ionic Compounds (ex: NaCl)
Acids (ex: HCl)
Bases (ex: NaOH)

32. Who Will Conduct?
Which of the following compounds will conduct in solution?
C6H12O6
LiBr
KOH
CH4
H2SO4
NO2

33. C6H12O6 Will Not (Covalent)
LiBr Will (Ionic)
KOH Will (Base)
CH4 Will Not (Covalent)
H2SO4 Will (Acid)
NO2 Will Not (Covalent)

34. Reference Table F
Describes which ionic compounds are soluble or insoluble in water.

35. Why are Some Insoluble?
Certain combinations of ions hold together so strongly that water cannot dissolve them into solution

36. Precipitates
Precipitates are insoluble ionic compounds formed in double replacement reactions.
Determine which product is the insoluble precipitate by using Table F.

37. You can separate a precipitate by filtration.
The solid will stay on the paper.

38. Is this soluble or not? CaCO3
Carbonate (CO3-2) is insoluble and Ca+2 as a partner is not an exception

39. Is this soluble or not? NaNO3
Nitrate (NO3-1) is always soluble, there are not exceptions

40. Is this soluble or not? Li3PO4
Phosphate (PO4-3) is insoluble, however, Li+1 is a Group 1 ion so it is an exception and the compound is soluble.

41. Soluble or Not?
Look out for exceptions!
CaSO4
MgSO4
PbCrO4
Li2S
NH4OH

42. Insoluble CaSO4
Soluble MgSO4
Insoluble PbCrO4
Soluble Li2S
Soluble NH4OH