Single & Double Replacement Reactions KEY
AP Directions: For each of the following reactions, in part (i) write a balanced equation for the reaction and in part (ii) answer the
question about the reaction. In part (i), coefficients should be in terms of lowest whole numbers. Assume that solutions are aqueous unless otherwise indictated. Represent substances in solutions as ions if the substances are extensively ionized. Omit formulas for any ions or molecules that are unchanged by the reaction.
Mrs. Weston Directions: Write BALANCED NET IONIC equations & answer the question in part (ii).
(A) A strip of zinc is added to a solution of 6.0-molar hydrobromic acid.
(i) Balanced equation: Zn + 2 H+  Zn2+ + H2
(ii) How many moles of zinc would react completely with 500. mL of 6.0 M hydrobromic acid?
.500 L x 6.0 M = 3.0 moles of HBr x 1 mole Zn / 2 mol HBr = 1.5 mol HBr
(B) Liquid bromine is shaken with a 0.5 M sodium iodide solution.
(i) Balanced equation: Br2 + 2 I-  Br- + I2
(ii) What is the oxidation number of bromine before and after the reaction occurs?
Before = 0; After = -1
(C) A mixture of powdered iron(III) oxide and powdered aluminum metal is heated strongly.
(i) Balanced equation: Fe2O3 + 2 Al  Fe + Al2O3
(ii) Name the element being oxidized and reduced.
Aluminum is oxidized and iron is reduced.
(D) A solution of copper(II) chloride is added to a solution of sodium sulfide.
(i) Balanced equation: Cu2+ + S2–  CuS
(ii) If 2.0 L of 1.0 M solutions of copper (II) chloride and sodium sulfide are mixed together, how many moles of product(s) will
be produced? Assume the reaction goes to completion.
2.0 L x 1.0 M = 2.0 mol reactant = 2.0 mol product
(E) A bar of strontium metal is immersed in 1.0 M copper (II) nitrate solution.
(i) Balanced equation: Sr + Cu2+  Cu + Sr2+
(ii) What type of reaction is this?
Single replacement or redox reaction
(F) A piece of copper wire is placed in a solution of silver nitrate.
(i) Balanced equation: Cu + Ag+  Cu2+ + Ag
(ii) List at least two observations that a chemical reaction has occurred.
Solution turns from clear to blue. Silver is formed on copper metal.
(G) A 0.02 M hydrochloric acid solution is mixed with an equal volume of 0.01 M calcium hydroxide.
(i) Balanced equation: OH– + H+  H2O
(ii) List all spectator ions.
Cl- and Ca2+
(H) A solution of copper(II) sulfate is spilled onto a sheet of freshly polished aluminum metal.
(i) Balanced equation: 2 Al + 3 Cu2+  3 Cu + 2 Al3+
(ii) What is the oxidizing agent in this reaction?
Copper
(I)
A 0.1 M nitrous acid solution is added to the same volume of a 0.1 M sodium hydroxide solution.
HNO2 + OH–  H2O + NO2–
(i) Balanced equation:
(ii) What type of reaction is this?
Acid-base neutralization reaction
(J)
A solution of sodium phosphate is added to a solution of aluminum nitrate.
3–
(i) Balanced equation: PO4 + Al3+  AlPO4
(ii) List any precipitate the forms during the reaction.
AlPO4