Solubility rules:
Answers to lab
Br –
Ag+
Al3+
Ba2+
Ca2+
Co2+
Cu2+
Fe3+
X
Cl – CO32– NO3 – OH – PO43– SO32– SO42–
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
K+
Na+
Ni2+
NH4+
X
Answers 1 - 8
Alkali metals (IA)
2. NH4+
NO3– 4. Br –, Cl –, SO42–
NO3– 6. Na+ or K+ or NH4+
Ag3PO4
AlPO4
Ba3(PO4)2
Ca3(PO4)2 Co3(PO4)2 Cu3(PO4)2
FePO4
Ni3(PO4)2
8. Ca(NO3)2 Soluble rule 2
FeCl3
Soluble rule 3
Ni(OH)2
Insoluble rule 5
AgNO3
Soluble rule 2
BaSO4
Insoluble rule 4
CuCO3
Insoluble rule 6
1.
3.
5.
7.
Answer 9
You have a mixture of Ba2+, Pb2+, Cu2+, Na+
Which can be precipitated without the others?
Use Cl –, Br –, or I – to precipitate Pb2+ (rule 3)
Filtering leaves Ba2+, Cu2+, Na+
Use SO42– to precipitate Ba2+ (rule 4)
Filtering leaves Cu2+, Na+
Use OH – (rule 5), or any of PO43–, CO32–, SO32–,
S2– (rule 6) to precipitate Cu2+
Since all Na+ compounds are soluble, this will
stay in solution
Determining net ionic reactions
Step 1: Write formula for reactants and products
using valences. Products are
determined by switching +ve and –ve.
Step 2: Determine if any products are insoluble
(use solubility rules). Note: all reactants
must be soluble (i.e. aq) in order to mix.
If all products are aqueous: “no reaction”
Step 3: Balance the equation
Step 4: Write the ionic equation
Step 5: Write the net ionic equation
E.g. sodium phosphate + calcium chloride
Answers: 10 i) and ii)
i)
(NH4)2S(aq) + Pb(NO3)2(aq)  PbS(s) + 2NH4NO3(aq)
2NH4+(aq) + S2–(aq) + Pb2+(aq) + 2NO3–(aq)
 PbS(s) + 2NH4+(aq) + 2NO3–(aq)
Net: S2–(aq) + Pb2+(aq)  PbS(s)
ii)
Co(NO3)2(aq) + Na2SO4(aq)  No reaction
Step 1:
Step 2:
Step 3:
Step 4:
Step 5:
Write correct formulas
Determine if any products are insoluble
Balance the equation
Write the ionic equation
Write the net ionic equation
Answers: 10 iii) - vi)
iii) AgNO3(aq) + NaI(aq)  AgI(s) + NaNO3(aq)
Ag+(aq) + NO3–(aq) + Na+(aq) + I–(aq)
 AgI(s) + Na+(aq) + NO3–(aq)
Net: Ag+(aq) + I–(aq)  AgI(s)
iv)Al(NO3)3(aq) + 3KOH(aq)  Al(OH)3(s) + 3KNO3(aq)
Al3+(aq) + 3NO3–(aq) + 3K+(aq) + 3OH–(aq)
 Al(OH)3(s) + 3K+(aq) + 3NO3–(aq)
Net: Al3+(aq) + 3OH–(aq)  Al(OH)3(s)
v)Zn(NO3)2(aq) + K2CO3(aq)  ZnCO3(s) + 2KNO3(aq)
Zn2+(aq) + 2NO3–(aq) + 2K+(aq) + CO32–(aq)
 ZnCO3(s) + 2K+(aq) + 2NO3–(aq)
Net: Zn2+(aq) + CO32–(aq)  ZnCO3(s)
vi) KCl(aq) + NaNO3(aq)  No reaction
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