Unit 2 | Topics: Solubility, Complex Ions | 17-18

Question 1

solubility

Answer 1

the amount of solid that must dissolve to produce a saturated solution

Question 2

precipitation

Answer 2

when and how much solid will precipitate out of solution

Question 3

solubility product Ksp

Answer 3

equilibrium constant for equilibrium established b/w a solid solute and its ions in a solution

Question 4

saturated solution

Answer 4

a solution with the maximum conc of dissolved ions with the solution in contact with extra..

Question 5

determining Ksp from solubility

Answer 5

1. calculate molar solubility (mol/L) - use molar mass to get mol
2. ICE table
3. Ksp = [products]^corresponding stoich coff

Question 6

determining solubility from Ksp

Answer 6

1. make ice table
2. solve for s

Question 7

comparing solubilities

Answer 7

if salts being compared dissolve into SAME number of ions, then their Ks values can be directly compared to predict their relative solubilities
if compared DIFFERENT number of ions, solubilities must be calculated explicitly, then compared

Question 8

Precipitation: If
Q> Ksp
Q<Ksp
Q=Ksp

Answer 8

Q> Ksp - rxn proceeds, left (rev) precipitation occurs
Q<Ksp - right (fwd), no percipitation
Q=Ksp - saturated (at equilibrium) no change

Question 9

Soluble salts

Answer 9

1. nitrates (NO3-) salts
2. Alkali Metals (K+, Na+) and ammonium salt NH4+
3. Chloride, Bromide, Iodide except with: Ag+, Pd2+, Hg22+
   4.Sulfate (SO42-) except with Sr2+, Ba2+, Pb2+, Hg22+

Question 10

Insoluble (or very weakly soluble)

Answer 10

1. OH, Hydroxide, except Group 1 and NH4+ salts
2. Sulfide (S2-) except Group 1 and NH4+ salts
3. Carbonate (CO32-) except Group 1 and NH4+ salts
4. Phosphate (PO43-) except Group 1 and NH4+ salts

Question 11

example: KCl and BaSO4

Answer 11

soluble, sparingly soluble (respectively)

Question 12

Predicting Precipitation formation

Answer 12

1. Write a balance equation and determine the solubility of all species
2. Calculate Q, determine initial concentrations of the insoluble species
   3.if Q>Ksp = precipitate will form

Question 13

Selective Precipitation

Answer 13

mixtures of 2 or more ions can be separated by using a reagent that will form a precipitate with only one of the ones