CH 115 Fall 2014
Worksheet 21
1. What is a double-replacement reaction? What is a precipitation reaction?
A double replacement reaction is one in which the cations in two compounds
swap places. It can be generally visualized as: AX + BY  BX + AY. A
precipitation reaction is a special type of double-replacement reaction in
which one of the products formed is a solid, insoluble ionic compound.
2. Write and balance the following chemical reactions that will take place.
a). Lead (II) nitrate mixed with sodium chloride
Pb(NO3)2 (aq) + 2 NaCl (aq)  PbCl2 (s) + 2 NaNO3 (aq)
b). Iron (II) sulfate mixed with magnesium nitrate
FeSO4 (aq) + Mg(NO3)2 (aq)  Fe(NO3)2 (aq) + MgSO4 (aq)
c). Potassium hydroxide mixed with magnesium sulfate
2 KOH (aq) + MgSO4 (aq)  Mg(OH)2 (s) + K2SO4 (aq)
d). Calcium chloride mixed with potassium carbonate
CaCl2 (aq) + K2CO3 (aq)  CaCO3 (s) + 2 KCl (aq)
e). Silver nitrate mixed with barium chloride
2 AgNO3 (aq) + BaCl2 (aq)  2 AgCl (s) + Ba(NO3)2 (aq)
f). Copper (II) nitrate mixed with sodium hydroxide
Cu(NO3)2 (aq) + 2 NaOH (aq)  Cu(OH)2 (s) + 2 NaNO3 (aq)
3. What is a total ionic equation? What is a net ionic equation? What is the process for
writing both of these equations?
To write a total ionic equation, break up all of the compounds that are
aqueous into their ionic components. To write a net ionic equation, cross out
all the spectator ions (ions that are present on both the reactants and
products side of the equation). A net ionic equation shows you which ions
actually react. NEVER break apart solids, liquids, gases, or weak acids when
writing a total or net ionic equation.
4. Can you write a total and net ionic equations for each of the chemical reactions
given in question #2?
a). Total – Pb2+ (aq) + 2 NO3- (aq) + 2 Na+ (aq) + 2 Cl- (aq)  PbCl2 (s) + 2 Na+
(aq) + 2 NO3- (aq)
Net – Pb2+ (aq) + 2 Cl- (aq)  PbCl2 (s)
b). Total – Fe2+ (aq) + SO42- (aq) + Mg2+ (aq) + 2 NO3- (aq)  Fe2+ (aq) + 2 NO3(aq) + Mg2+ (aq) + SO42- (aq)
Net – none (all ions cross out)
c). Total – 2 K+ (aq) + 2 OH- (aq) + Mg2+ (aq) + SO42- (aq)  Mg(OH)2 (s) + 2 K+
(aq) + SO42- (aq)
Net – 2 OH- (aq) + Mg2+ (aq)  Mg(OH)2 (s)
d). Total – Ca2+ (aq) + 2 Cl- (aq) + 2 K+ (aq) + CO32- (aq)  CaCO3 (s) + 2 K+ (aq) +
2 Cl- (aq)
CH 115 Fall 2014
Worksheet 21
Net – Ca2+ (aq) + CO32- (aq)  CaCO3 (s)
e). Total – 2 Ag+ (aq) + 2 NO3- (aq) + Ba2+ (aq) + 2 Cl- (aq)  2 AgCl (s) + Ba2+
(aq) + 2 NO3- (aq)
Net – 2 Ag+ (aq) + 2 Cl- (aq)  2 AgCl (s)
f). Total – Cu2+ (aq) + 2 NO3- (aq) + 2 Na+ (aq) + 2 OH- (aq)  Cu(OH)2 (s) + 2
Na+ (aq) + 2 NO3- (aq)
Net – Cu2+ (aq) + 2 OH- (aq)  Cu(OH)2 (s)