a. How might you use a precipitation reaction to prepare a sample of Ca 3 (PO 4
ID: 789803 • Letter: A
Question
a. How might you use a precipitation reaction to prepare a sample of Ca3(PO4)2? Write a molecular equation and then the net ionic equation.
b. Assume that you have an aqueous mixture of NaNO3 and AgNO3. How could you use a precipitation reaction to separate the two metal ions? (What third compound would you add?) Write the molecular and net ionic equation for this reaction.
c. What precipitate forms when aqueous solutions of potassium chloride, sodium perchlorate, and lead(II) nitrate are simultaneously mixed? Show the molecular and net ionic equation for this reaction.
Explanation / Answer
a) How might you use a precipitation reaction to prepare a sample of Ca3(PO4)2? Write a molecular equation and then the net ionic equation.
We need Ca2+ and PO4-3 ions...
Add Ca(NO3)2(aq) so there is Ca2+(aq), this is soluble
Add H3PO4(aq), which is phosphoric acid
Now, both will be present
3Ca(NO3)2(aq) + 2H3PO4(aq) = 6HNO3(aq) + Ca3(PO4)2(s)
3Ca2+(aq) + 6NO3-(aq) + 3H+(aq) + PO4-3(aq) = 6H+(aq) + 6NO3-(aq) + Ca3(PO4)2(s)
Now, write net ionicr equation
3Ca2+(aq) + 6NO3-(aq) = Ca3(PO4)2(s)
b. Assume that you have an aqueous mixture of NaNO3 and AgNO3. How could you use a precipitation reaction to separate the two metal ions? (What third compound would you add?) Write the molecular and net ionic equation for this reaction.
Ag+ ions are not soluble when we add Cl-; then add HCl(aq)
molecular
Ag+(aq) + HCl(aq) = AgCl(s) + H+(Aq)
net ionic:
Ag+(aq) + Cl-(aq) = AgCl(s)
filter AgCl crystals, only Na+ will be in solution
c. What precipitate forms when aqueous solutions of potassium chloride, sodium perchlorate, and lead(II) nitrate are simultaneously mixed? Show the molecular and net ionic equation for this reaction.
KCl(aq) + NaClO4(aq) + Pb(NO3)2(aq) mix:
Note that perchlorates are most soluble; some chlorides are NOT soluble,
therefore
molecular
2KCl(aq) + NaClO4(aq) + Pb(NO3)2(aq) = PbCl2(s) + NaClO4(aq) + 2KNO3(aq)
Pb2+(aq) + 2Cl-(aq) = PbCl2(s) will form
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.