Solubility
“The solubility of a substance is the amount of a substance that is required to form a saturated
solution in a given amount of solvent at a specific temperature.” ~Source CK-12 text
Remember:
Solute – the substance being dissolved
Solvent – substance doing the dissolving
If a solute is insoluble in water, then no amount of it will dissolve
If a solute is slightly soluble in water, then 1 gram of it requires 100-1000 ml of solvent to
dissolve
If a solute is insoluble in water, then no amount of it will dissolve (or 1 gram requires more
than 10,000 ml of solvent)
The rules of solubility are below. Complete the practice problems that follow
Solubility Rules
Predict if each compound would be soluble in water or not:
NaOH ___________
CaCO3 ___________
NH4NO3 __________
AgI ___________
BaSO4 ___________
AgNO3 ___________
Mg(OH)2 _________
CuS ___________
Reactions and Solubility
Chemistry cannot be seen directly, instead we infer what is happening from observations.
Often times we know a reaction occurred because a precipitate formed. A precipitate means
that one of the products of a chemical reaction was insoluble and therefore you visually see
the solid it creates.
One common reaction is the reaction of lead (II) nitrate and potassium iodide. Watch the
quick video of the reaction and use the solubility rules to determine what you are seeing…
Pb(NO3)2 (aq) + KI(aq)  _________(
)
+ _________(
)
What does the (aq) after each reactant mean?
What symbol do you use if a substance is NOT soluble?
For each reaction below predict the products of the reaction and then balance the equation.
Determine (using the chart) if the products would be soluble (aq) or insoluble (s).
1.
LiNO3 (aq) + KCl(aq)  ______________(
+ _______________
2.
AgNO3 (aq) + KCl(aq)  ______________(
3.
Na2S (aq) + HCl(aq)  ______________(
4.
NaOH (aq) + CaBr2(aq)  ______________(
5.
HCl (aq) + NaOH(aq)  ______________(
6.
Mg(OH)2 (aq) + HCl(aq)  ______________(
)
+ _______________
(
)
7.
Na2SO4 (aq) + SrCl2(aq)  ______________(
)
+ _______________
(
)
)
)
)
+ _______________
+ _______________
)
(
(
)
)
+ _______________
)
)
(
+ _______________
(
(
)
)
Which of the above reactions could you do in an experiment and actually “see” product being
created?
Pick 1 of the reactions your identified above. How many grams of each reactant will you need
to create 10 grams of the solid formed?