2004
4. Write the formulas to show the reactants and the products for any FIVE of the laboratory
situations described below. Answers to more than five choices will not be graded. In all
cases, a reaction occurs.
Assume that solutions are aqueous unless otherwise indicated. Represent
substances in solution as ions if the substances are extensively ionized. Omit
formulas for any ions or molecules that are unchanged by the reaction. You need
not balance the equations.
(a) A solution of copper(II) sulfate is spilled onto a sheet of freshly polished aluminum
metal.
(b) Dimethyl ether is burned in air.
(c) A 0.1 M nitrous acid solution is added to the same volume of a 0.1 M sodium
hydroxide solution.
(d) Hydrogen iodide gas is bubbled into a solution of lithium carbonate.
(e) An acidic solution of potassium dichromate is added to a solution of iron(II) nitrate.
(f) Excess concentrated aqueous ammonia is added to a solution of nickel(II) bromide.
(g) A solution of sodium phosphate is added to a solution of aluminum nitrate. (h)
Concentrated hydrochloric acid is added to a solution of sodium sulfide.
2003 C
4. Write the formulas to show the reactants and the products for any FIVE of the laboratory
situations described below. Answers to more than five choices will not be graded. In all
cases, a reaction occurs.
Assume that solutions are aqueous unless otherwise indicated. Represent substances in
solution as ions if the substances are extensively ionized. Omit formulas for any ions or
molecules that are unchanged by the reaction. You need not balance the equations.
(a) A solution of potassium phosphate is mixed with a solution of calcium acetate.
(b) Solid zinc carbonate is added to 1.0 M sulfuric acid.
(c) A solution of hydrogen peroxide is exposed to strong sunlight
.
(d) A 0.02 M hydrochloric acid solution is mixed with an equal volume of a 0.01 M
calcium hydroxide solution.
(e) Excess concentrated aqueous ammonia is added to solid silver chloride.
(f) Magnesium ribbon is burned in oxygen.
(g) A bar of strontium metal is immersed in a 1.0 M copper(II) nitrate solution.
(h) Solid dinitrogen pentoxide is added to water.
(a) PO43- + Ca2+ -> Ca3(PO4)2
(b) ZnCO3 + H+ -> Zn2+ + H2O + CO2
(c) H2O2 -> H2O + O2
(d) OH- + H+ -> H2O
(e) NH3 + AgCl_-> [Ag(NH3)2]+ + Cl(f) Mg + O2 -> MgO
(g) Sr + Cu2+ -> Cu + Sr2+
(h) N2O5 + H2O -> H+ + NO3-
2002 C
4. Write the formulas to show the reactants and the products for any FIVE of the
laboratory situations described below. Answers to more than five choices will not be
graded. In all cases, a reaction occurs. Assume that solutions are aqueous unless
otherwise indicated. Represent substances in solution as ions if the substances are
extensively ionized. Omit formulas for any ions or molecules that are unchanged by
the reaction. You need not balance the equations.
(a) Hot hydrogen gas is passed over heated copper(II) oxide solid.
(b) Solid sodium hydride is added to water.
(c) Propanone is burned in air.
(d) A solution of lead(II) nitrate is added to a solution of potassium sulfate.
(e) Ammonia gas is mixed with hydrogen chloride gas.
(f) Sulfur trioxide gas is bubbled into water.
(g) Excess concentrated potassium hydroxide solution is added to a solution of nickel(II) chloride.
(h) Solid sodium acetate is added to 1.0 M hydrobromic acid.
(a) I– + Pb2+  PbI2
(b) P4 + O2  P4O10
(c)
(d)
(e)
(f)
(g)
(h)
Cs2O + H2O  Cs+ + OH–
Cl– + Co3+  [CoCl4]2–
NaHCO3  Na2CO3 + H2O + CO2
H+ + ZnS  H2S + Zn2+
H+ + MnO4– + Fe2+  H2O + Mn2+ + Fe3+
OH– + NH4Cl  NH3 + H2O + Cl–
2001 C
4. Write the formulas to show the reactants and the products for any FIVE of the
laboratory situations described below. Answers to more than five choices will not be
graded. In all cases, a reaction occurs. Assume that solutions are aqueous unless
otherwise indicated. Represent substances in solution as ions if the substances are
extensively ionized. Omit formulas for any ions or molecules that are unchanged by
the reaction. You need not balance the equations.
(a) Sulfur dioxide gas is bubbled into distilled water.
SO2 + H2O  H2SO3
(b) A drop of potassium thiocyanate solution is added to a solution of iron(III) nitrate.
SCN– + Fe3+  FeSCN2+
(c) A piece of copper wire is placed in a solution of silver nitrate.
Cu + Ag+  Cu2+ + Ag
(d) Solutions of potassium hydroxide and propanoic acid are mixed.
OH– + C2H5COOH  C2H5COO– + H2O
(e) A solution of iron(II) chloride is added to an acidified solution of sodium dichromate.
Fe2+ + Cr2O72– + H+  Cr3+ + Fe3+ + H2O
(f) Chlorine gas is bubbled through a solution of potassium bromide.
Cl2 + Br–  Cl– + Br2
(g) Solutions of strontium nitrate and sodium sulfate are mixed.
Sr2+ + SO42–  SrSO4
(h) Powdered magnesium carbonate is heated strongly.
MgCO  MgO + CO2
3
2000 C
2000c
4. Write the formulas to show the reactants and the products for any FIVE of the
laboratory situations described below. Answers to more than five choices will not be
graded. In all cases, a reaction occurs. Assume that solutions are aqueous unless
otherwise indicated. Represent substances in solution as ions if the substances are
extensively ionized. Omit formulas for any ions or molecules that are unchanged by
the reaction. You need not balance the equations.
(a) A small piece of calcium metal is added to hot distilled water.
Ca + H2O  H + Ca(OH)2
[Ca2+ + OH–]??
2
(b) Butanol is burned in air.
C4H9OH + O  H2O + CO2
2
(c) Excess concentrated ammonia solution is added to a solution of nickel(II) sulfate.
Ni2+ + NH  Ni[NH ]62+
3
3
(d) A solution of copper(II) chloride is added to a solution of sodium sulfide.
Cu2+ + S2–  CuS
(e) A solution of tin(II) nitrate is added to a solution of silver nitrate.
Sn2+ + Ag+  Ag + Sn4+
(f) Excess hydrobromic acid solution is added to a solution of potassium hydrogen
carbonate.
H+ + HCO -  H2O + CO2
(g) Powdered strontium oxide is added to distilled water.
SrO + H2O  Sr(OH)2
(h) Carbon monoxide gas is passed over hot iron(III) oxide.
CO + Fe2O  Fe + CO2
3
3
1999 C
4.
(a) Calcium oxide powder is added to distilled water.
CaO + H2O  Ca(OH)2 (or Ca2+ + OH–)
(b) Solid ammonium nitrate is heated to temperatures above 300_C.
NH4NO3  N2 + O2 + H2O (or N2O + H2O)
(c) Liquid bromine is shaken with 0.5M sodium iodide solution.
Br2 + I–  I2 (or I3–) + Br–
(d) solid lead(II) carbonate is added to a 0.5M sulfuric acid solution.
PbCO3 + H+ + SO42–  PbSO4 + CO2 + H2O
(e) A mixture of powdered iron(III) oxide and powdered aluminum metal is heat
strongly.
Fe2O3 + Al  Al2O3 + Fe
(f) Methylamine gas is bubbled into distilled water.
CH3NH2 + H2O  CH3NH3+ + OH–
(g) Carbon dioxide gas is passed over hot, solid sodium oxide.
CO2 + Na2O  Na2CO3
(h) A 0.2M barium nitrate solution is added to an alkaline 0.2M potassium chromate
solution.
Ba2+ + CrO42–  BaCrO4
1994 C
a) Excess sodium cyanide solution is added to a solution of silver nitrate.
CN– + Ag+  Ag(CN)2–
b) Solutions of manganese(II) sulfate and ammonium sulfide are mixed.
Mn2+ + S2–  MnS(s)
c) Phosphorus(V) oxide powder is sprinkled over distilled water.
P4O10 (or P2O5) + H2O  H3PO4
d) Solid ammonium carbonate is heated.
(NH4)2CO3  NH3 + CO2 + H2O
e) Carbon dioxide gas is bubbled through a concentrated solution of potassium
hydroxide.
CO2 + OH–  CO32– + H2O
f) A concentrated solution of hydrochloric acid is added to solid potassium
permanganate.
KMnO4 + H+ + Cl–  Cl2 + Mn2+ + H2O + K+
g) A small piece of sodium metal is added to distilled water.
Na + H2O  Na+ + OH– + H2
h) A solution of potassium dichromate is added to an acidified solution of iron(II)
chloride.
Cr2O72– + H+ + Fe2+  Cr3+ + H2O + Fe3+
1995 C
a) Ethanol is burned in oxygen.
C2H5OH + O2  CO2 + H2O
b) Solid barium oxide is added to distilled water.
BaO + H2O  Ba2+ + OH–
c) Chlorine gas is bubbled into a cold, dilute solution of potassium hydroxide.
Cl2 + OH–  Cl– + ClO– (or ClO–/ClO2–/ClO3–) + H2O
d) A solution of iron(II) nitrate is exposed to air for an extended period of time.
Fe2+ + O2 (+ H2O)  Fe2O3 or FeO(OH) or Fe(OH)3
e) Excess concentrated sulfuric acid is added to solid calcium phosphate.
H+ + SO42– + Ca3(PO4)2  CaSO4 (or ions) + H3PO4
f) Hydrogen sulfide gas is bubbled into a solution of mercury(II) chloride.
H2S + Hg2+  HgS + H+ or
H2S + HgCl2  HgS + H+ + Cl–
g) Solid calcium hydride is added to distilled water.
CaH2 + H2O  Ca(OH)2 [or Ca2+ + OH–] + H2
h) A bar of zinc metal is immersed in a solution of cupper(II) sulfate.
Zn + Cu2+  Zn2+ + Cu
1996 C
a) solid calcium carbonate is strongly heated.
CaCO3  CaO + CO2
b) a piece of nickel metal is immersed in a solution of copper(II) sulfate.
Ni + Cu2+  Ni2+ + Cu
c)
equal volumes of equimolar solutions of disodium hydrogen phosphate and
hydrochloric acid are mixed.
HPO42– + H+  H2PO4–
d) chlorine gas is bubbled into a solution of sodium bromide.
Cl2 + Br–  Cl– + Br2
e) ammonia gas is bubbled into a solution of ethanoic (acetic) acid.
NH3 + CH3COOH  NH4+ + CH3COO–
f) solid ammonium carbonate is added to a saturated solution of barium hydroxide.
(NH4)2CO3 + Ba2+ + OH–  NH3 + BaCO3 + H2O
g) drops of liquid dinitrogen trioxide are added to distilled water.
N2O3 + H2O  HNO2
h) solutions of potassium permanganate and sodium oxalate are mixed.
MnO4– + C2O42–  MnO2 + CO2
1997 C
a) excess potassium hydroxide solution is added to a solution of aluminum nitrate.
OH– + Al3+  Al(OH)3 (or Al(OH)4–; Al(OH)4(H2O)2–; Al2O3; Al2O3•x H2O;
AlO2–)
b) a solution of sodium bromide is added to an acidified solution of potassium bromate.
Br– + H+ + BrO3–  Br2 + H2O
c) sulfur dioxide gas is bubbled into distilled water.
SO2 + H2O  H2SO3 (or  H+ + HSO3–; or  H+ + HSO3– + SO32–)
d) phosphine (phosphorus trihydride) gas is bubbled into liquid boron trichloride.
PH3 + BCl3  PH3BCl3
e)
hydrogen gas is passed over hot iron(II) oxide powder.
H2 + FeO  Fe + H2O
f) solid potassium amide is added to distilled water.
KNH2 + H2O  NH3 + OH– + K+ (or  NH4OH + OH– + K+)
g) a strip of magnesium metal is heated strongly in pure nitrogen gas.
Mg + N2  Mg3N2
h) a solution of nickel chloride is added to a solution of sodium sulfide.
Ni2+ + S2–  NiS (or Ni2+ + H2S  NiS + H+; or Ni2+ + HS–  NiS + H+)
1998 C
a) Solutions of tin(II) chloride and iron(III) chloride are mixed.
Sn2+ + Fe3+  Sn4+ + Fe2+
b) Solutions of cobalt(II) nitrate and sodium hydroxide are mixed.
Co2+ + OH–  Co(OH)2
c) Ethene gas is burned in air.
C2H4 + O2  CO2 + H2O
d) Equal volumes of equimolar solutions of phosphoric acid and potassium hydroxide
are mixed.
H3PO4 + OH–  H2PO4– + H2O
e) Solid calcium sulfite is heated in a vacuum.
CaSO3  CaO + SO2
f) Excess hydrochloric acid is added to a solution of diamminesilver(I) nitrate.
H+ + Cl– + Ag(NH3)2+  AgCl + NH4+
g) Solid sodium oxide is added to distilled water.
Na2O + H2O  Na+ + OH–
h) A strip of zinc is added to a solution of 6.0-molar hydrobromic acid.
Zn + H+  Zn2+ + H2