Name _____________
Write formulas for the reactants and predicted products for the chemical reactions that
follow. Assume that in all cases a reaction occurs. The equation must be balanced. Write
all substances in their proper form –as ions if appropriate – and cancel any spectator ions.
1.
Solutions of tin(II) chloride and iron(III) chloride are mixed.
Sn2+ + 2 Fe3+
2.
Sn4+ + 2 Fe2+
Solutions of cobalt(II) nitrate and sodium hydroxide are mixed.
Co2+ + OH-
3.
Co(OH)2 (s)
Ethene gas is burned in air.
C2H4 + 3 O2
4.
2 CO2 + 2 H2O
Equal volumes of equimolar solutions of phosphoric acid and potassium hydroxide are
mixed.
H3PO4 + OH-
5.
Solid calcium sulfite is heated in a vacuum.
CaSO3
6.
H2PO4- + H2O
CaO + SO2
Excess hydrochloric acid is added to a solution of diamminesilver(I) nitrate.
2 H+ + Cl- + [Ag(NH3)2]+
2NH4+ + AgCl
2 H+ + 2 Cl- + [Ag(NH3)2]+
2 NH4+ + AgCl2-
(AgCl2- as a product is possible if the HCl is concentrated and in excess)
7.
Solid sodium oxide is added to distilled water.
Na2O + H2O
8.
2 Na+ + 2 OH-
A strip of zinc is added to a solution of 6.0-molar hydrobromic acid.
Zn + 2 H+
H2 + Zn2+
9.
Excess potassium hydroxide solution is added to a solution of aluminum nitrate.
Al3+ + 3 OH-
Al(OH)3
Other acceptable products: Al(OH)4-; Al(OH)4(H2O)2-; Al2O3 xH2O; AlO210.
A solution of sodium bromide is added to an acidified solution of potassium bromate.
24 H+ + 10 Br- + 4 BrO3-
11.
Sulfur dioxide gas is bubbled into distilled water.
H2SO3 (or H+ + HSO3- or H+ + HSO3- + SO32-)
SO2 + H2O
12.
Phosphine (phosphorus trihydride) gas is bubbled into liquid boron trichloride.
PH3 + BCl3
13.
H3PBCl3
Hydrogen gas is passed over hot iron(II) oxide powder.
H2 + FeO
14.
H2O + Fe
Solid potassium amide is added to distilled water.
KNH2 + H2O
15.
Mg3N2
A solution of nickel chloride is added to a solution of sodium sulfide.
Ni2+ + S2-
17.
NH3 + OH- + K+ (or NH4OH + OH- + K+)
A strip of magnesium metal is heated strongly in pure nitrogen gas.
3 Mg + N2
16.
7 Br2 + 12 H2O
NiS
Ni2+ + H2S
NiS + 2 H+
Ni2+ + HS-
NiS + H+
Solid calcium carbonate is strongly heated.
CaCO3
CaO + CO2
18.
A piece of nickel metal is immersed in a solution of copper(II) sulfate.
Ni + Cu2+
Ni2+ + Cu
hydrated ions acceptable with correct charge; partial credit for Ni(OH)2 as product
19.
Equal volumes of equimolar solutions of disodium hydrogen phosphate and hydrochloric
acid are mixed.
HPO42- + H+
H2PO4-
incorrect charge on H2PO4- when only one product occurs, partial credit; partial credit for
transfer if H+ from an ionic reactant to product when a phosphate species is incorrectly
but consistently written.
20.
Chlorine gas is bubbled into a solution of sodium bromide.
Cl2 + 2 Br-
2 Cl- + Br2
no credit for monatomic Cl as reactant or Br as product
21.
Ammonia gas is bubbled into a solution of ethanoic (acetic) acid.
NH3 + HC2H3O2
C2H3O2- + NH4+
partial credit for NH4C2H3O2; partial credit for NH3 + H+
22.
NH4
Solid ammonium carbonate is added to a saturated solution of barium hydroxide.
(NH4)2CO3 + Ba2+ + 2 OH-
2 NH3 + BaCO3 + 2 H2O
partial credit for either NH3 or BaCO3; partial credit for all three species correct
23.
Drops of liquid dinitrogen trioxide are added to distilled water.
N2O3 + H2O
2 HNO2
partial credit for H+ + NO224.
Solutions of potassium permanganate and sodium oxalate are mixed.
4 H+ + MnO4- + 3 C2O42-
MnO2 + 6 CO2 + 2 H2O
no penalty for OH- or H2O in equation; no credit earned for Mn2+ as product