EXAM 3 CHEM 1310 WS09 Key
Version #1
1. (p. 87) How many grams of sodium fluoride (used in water fluoridation and manufacture of
insecticides) are needed to form 485 g of sulfur tetrafluoride?
3SCl2(l) + 4NaF(s)  SF4(g) + S2Cl2(l) + 4NaCl(s)
a. 1940 g
b. 1510 g
c. 205 g
d. 51.3 g
E. 754 g
Difficulty: M
Silberberg - 003 Stoichiometry... #40
2. (p. 77) A compound containing chromium and silicon contains 73.52 mass percent chromium.
Determine its empirical formula.
a. Cr3Si
b. CrSi3
c. Cr2S
d. Cr2Si3
E. Cr3Si2
Difficulty: M
Silberberg - 003 Stoichiometry... #25
3. (p. 119) Select the net ionic equation for the reaction between lithium hydroxide and
hydrobromic acid.
LiOH(aq) + HBr(aq)  H2O(l) + LiBr(aq)
a. LiOH(aq)  Li+(aq) + OH-(aq)
b. Li+(aq) + Br-(aq)  LiBr(aq)
C. H+(aq) + OH-(aq)  H2O(l)
d. Li+(aq) + OH-(aq) + H+(aq) + Br-(aq)  H2O(l) + LiBr(aq)
e. HBr(aq)  H+(aq) + Br-(aq)
Difficulty: E
Silberberg - 004 The... #29
4. (p. 125) Calculate the oxidation number of the chlorine in perchloric acid, HClO4, a strong
oxidizing agent.
a. +4
b. None of these is the correct oxidation number.
c. +5
d. -1
E. +7
Difficulty: E
Silberberg - 004 The... #34
5. (p. 112) Which of the following is most soluble in water?
a. hexane, C6H14
b. ethane, C2H4
C. potassium nitrate, KNO3
d. carbon tetrachloride, CCl4
e. benzene, C6H6
Difficulty: E
Silberberg - 004 The... #8
6. (p. 82) Balance the following equation:
Ca3(PO4)2(s) + SiO2(s) + C(s)  CaSiO3(s) + CO(g) + P4(s)
a. 2Ca3(PO4)2(s) + 6SiO2(s) + 10C(s)  6CaSiO3(s) + 10CO(g) + 4P4(s)
B. 2Ca3(PO4)2(s) + 6SiO2(s) + 10C(s)  6CaSiO3(s) + 10CO(g) + P4(s)
c. Ca3(PO4)2(s) + 3SiO2(s) + 8C(s)  3CaSiO3(s) + 8CO(g) + P4(s)
d. Ca3(PO4)2(s) + 3SiO2(s) + 14C(s)  3CaSiO3(s) + 14CO(g) + P4(s)
e. Ca3(PO4)2(s) + 3SiO2(s) + 8C(s)  3CaSiO3(s) + 8CO(g) + 2P4(s)
Difficulty: M
Silberberg - 003 Stoichiometry... #35
7. (p. 116) Select the precipitate that forms when aqueous ammonium sulfide reacts with aqueous
copper(II) nitrate.
a. NH4NO3
b. NH4(NO3)2
C. CuS
d. CuSO4
e. Cu2S
Difficulty: M
Silberberg - 004 The... #18
8. (p. 111) How many sodium ions are present in 325 mL of 0.850 M Na2SO4?
a. 1.57  1024 Na ions
b. 1.66  1023 Na ions
c. 4.99  1023 Na ions
d. 6.20  1023 Na ions
E. 3.33  1023 Na ions
Difficulty: M
Silberberg - 004 The... #7
9. (p. 120) A 0.00100 mol sample of Ca(OH)2 requires 25.00 mL of aqueous HCl for neutralization
according to the reaction below. What is the concentration of the HCl?
Equation: Ca(OH)2(s) + 2HCl(aq)  CaCl2(aq) + H2O(l)
a. None of these choices is correct.
b. 4.00  10-5 M
c. 0.0200 M
d. 0.0400 M
E. 0.0800 M
Difficulty: M
Silberberg - 004 The... #33
10. (p. 94) Tetraphosphorus hexaoxide (
with oxygen gas.
= 219.9 g/mol) is formed by the reaction of phosphorus
P4(s) + 3O2(g)  P4O6(s)
If a mixture of 75.3 g of phosphorus and 38.7 g of oxygen produce 43.3 g of P4O6, what is the
percent yield for the reaction?
a. 38.0%
b. 16.3%
C. 48.8%
d. 57.5%
e. 32.4%
Difficulty: M
Silberberg - 003 Stoichiometry... #51
11. (p. 125) Which one of the following is a redox reaction?
a. Na2CO3(s) + 2HCl(aq)  2NaCl(aq) + CO2(g) + H2O(l)
b. Ba2+(aq) + SO42-(aq)  BaSO4(s)
c. H2O(l)  H+(aq) + OH-(aq)
D. 2Na(g) + Cl2(g)  2NaCl(s)
e. K2Cr2O7(aq) + 2KOH(aq)  2K2CrO4(aq) + H2O(l)
Difficulty: M
Silberberg - 004 The... #43
12. (p. 114) In the following reaction, what ions, if any, are spectator ions?
Pb(NO3)2(aq) + 2NaCl(aq)  PbCl2(s) + 2NaNO3(aq)
A. Na+(aq), NO3-(aq)
b. Pb2+(aq), NO3-(aq)
c. There are no spectator ions
d. Pb2+(aq), Cl-(aq)
e. Na+(aq), Cl-(aq)
Difficulty: E
Silberberg - 004 The... #15
13. (p. 120) Automobile batteries use 3.0 M H2SO4 as an electrolyte. How much 1.20 M NaOH will
be needed to neutralize 225 mL of battery acid?
H2SO4(aq) + 2NaOH(aq)  2H2O(l) + Na2SO4(aq)
a. 0.28 L
b. 0.90 L
c. 0.56 L
D. 1.1 L
e. 0.045 L
Difficulty: M
Silberberg - 004 The... #31
14. (p. 77) Hydroxylamine hydrochloride is a powerful reducing agent which is used as a
polymerization catalyst. It contains 5.80 mass % H, 20.16 mass % N, 23.02 mass % O, and 51.02
mass % Cl. What is its empirical formula?
a. H4NOCl2
B. H4NOCl
c. H2N7O8Cl18
d. HN3O4Cl9
e. H2N2O2Cl
Difficulty: M
Silberberg - 003 Stoichiometry... #29
15. (p. 125) Identify the oxidizing agent in the following redox reaction.
Hg2+(aq) + Cu(s)  Cu2+(aq) + Hg(l)
A. Hg2+(aq)
b. Cu(s)
c. Hg2+(aq) and Cu2+(aq)
d. Hg(l)
e. Cu2+(aq)
Difficulty: E
Silberberg - 004 The... #39
16. (p. 116) Select the precipitate that forms when the following reactants are mixed.
Na2CO3(aq) + BaCl2(aq) 
A. BaCO3
b. NaCl2
c. Ba2CO3
d. NaCl
e. BaO
Difficulty: E
Silberberg - 004 The... #16
17. (p. 111) How many moles of ions are released when 0.27 mol of cobalt(II) chloride, CoCl2, is
dissolved in water?
a. 0.27 mol
b. 0.090 mol
c. 0.54 mol
d. 0.18 mol
E. 0.81 mol
Difficulty: E
Silberberg - 004 The... #3
18. (p. 116) Select the correct name and chemical formula for the precipitate that forms when the
following reactants are mixed.
CuCl2(aq) + Na2CO3(aq) 
a. copper(I) carbonate, Cu2CO3
b. copper(II) carbonate, Cu2CO3
c. copper(I) carbonate, CuCO3
D. copper(II) carbonate, CuCO3
e. sodium chloride, NaCl
Difficulty: M
Silberberg - 004 The... #20
19. (p. 111) How many moles of H+(aq) ions are present in 750 mL of 0.65 M hydrochloric acid?
a. 0.98 mol
b. 1.2 mol
C. 0.49 mol
d. 0.87 mol
e. 0.65 mol
Difficulty: E
Silberberg - 004 The... #5
20. (p. 111) Potassium carbonate, K2CO3, sodium iodide, NaI, magnesium oxide, MgO, methanol,
CH3OH, and ammonium chloride, NH4Cl, are soluble in water. Which produces the largest
number of dissolved particles per mole of dissolved solute?
a. NH4Cl
b. MgO
c. NaI
D. K2CO3
e. CH3OH