1. No category

Chemistry 131
Clark College
Exam 2 Review Sheet
The answers to this sample exam are on the last page of this handout. This review is not complete!
Please note that the exam will be a combination of multiple choice and problem solving. For practice
solving problems, please refer to the lecture notes, suggested problems, homework assignments and
the stoichiometry practice problems. Exam two will cover Chapter 4, 5 and 7.
1. Fumaric acid, which occurs in many plants, contains, by mass, 41.4% carbon, 3.47% hydrogen, and
55.1% oxygen. A 0.050-mol sample of this compound weighs 5.80 g. The molecular formula of this
compound is
a.CHO.
b. C3H3O.
c. C3H3O3.
d. C4H4O4.
e. C6H6O6.
2. The analysis of an organic compound showed that it contained 0.175 mol of C, 0.140 mol of H, and
0.0350 mol of N. Its molecular mass is about 160. How many atoms of carbon are there in the
empirical formula for the compound and how many in the molecular formula?
a.empirical = 2, molecular = 3
b.empirical = 3, molecular = 6
c.empirical = 3, molecular = 9
d.empirical = 5, molecular = 10
e.empirical = 5, molecular = 12
3. All the following equations are balanced EXCEPT
a.(NH4)2Cr2O7  N2O + Cr2O3 + 4H2O.
b. 2NH4SCN + Ba(OH)2 • 8H2O  2NH3 + 10H2O + Ba(SCN)2.
c.C12H22O11  12C + 11H2O.
d.NH4NO3  N2O + 2H2O.
e. 2Mg + CO2  2MgO + C.
4. All the following reactions can be described as displacement reactions EXCEPT
a.Zn(s) + FeCl2(aq)  ZnCl2(aq) + Fe(s).
b.CuSO4(aq) + Fe(s)  Cu(s) + FeSO4(aq).
c. 2Na(s) + 2H2O(l)  2NaOH(aq) + H2(g).
d. C6H6(l) + Cl2(g)  C6H5Cl(l) + HCl(g).
e.Cu(s) + 2AgNO3(aq)  Cu(NO3)2(aq) + 2Ag(s).
5. All the following reactions are called combination reactions EXCEPT
a.Br2(l) + H2O(l)  HOBr(aq) + HBr(aq).
b.BaO(s) + SO2(g)  BaSO3(s).
c. C6H10(l) + Br2(l)  C6H10Br2(l).
d.CaCl2(s) + 6H2O(l)  CaCl2 • 6H2O(s).
e. 3H2(g) + N2(g)  2NH3(g).
6. All the following reactions are described as decomposition reactions EXCEPT
a.(NH4)2Cr2O7(s)  N2(g) + 4H2O(g) + Cr2O3(s).
b.NH4HS(s)  NH3(g) + H2S(g).
c. 2CH3OH(l) + 3O2(g)  2CO2(g) + 4H2O(g).
d.PCl5(l)  PCl3(g) + Cl2(g).
e. 2CO2(g)  2CO(g) + O2(g).
Exam 2 Review
Ch. 4, 5 and 7
Page 1 of 4
Chemistry 131
Clark College
7. All the following reactions can be described as displacement reactions EXCEPT
a.Fe(s) + 2HCl(aq)  FeCl2(g) + H2(g).
b.CH4(g) + Br2(g)  CH3Br(g) + HBr(g).
c.Mg(s) + Hg(NO3)2(aq)  Mg(NO3)2(aq) + Hg(l).
d. 3CuCl2(aq) + 2Al(s)  3Cu(s) + 2AlCl3(aq).
8. Each of the following pairs contains a strong acid and a weak acid, respectively, EXCEPT
a.HNO3 and HNO2.
b.HCl and HBr.
c. H2SO4 and H2SO3.
d.HI and HC2H3O2.
e.HClO4 and HClO.
9.All the following are strong electrolytes in aqueous solution EXCEPT
a.Na3PO4.
b.NH4H2PO4.
c.NH3.
d.Na2HPO4.
e.NaH2PO4.
10. Which of the following ionic compounds is INSOLUBLE in water?
a.(NH4)2CO3
b.AgBr
c.CuSO4
d. KI
e.LiNO3
11. A precipitate is expected when an aqueous solution of potassium iodide is added to an aqueous
solution of
a.sodium sulfate.
b.iron(II) chloride.
c.calcium perchlorate.
d.barium hydroxide.
e.lead nitrate.
12. A compound dissolves in water to form an aqueous solution that is a poor conductor of electricity.
The compound may be composed of
a.covalent molecules.
b.a strong acid.
c.a strong base.
d.a soluble salt.
e.ions.
13. What products result from the addition of aqueous solutions of Cu(NO3)2 and (NH4)2S?
a.CuS(aq) and NH4NO3(s)
b.CuS(s) and NH4NO3(s)
c.CuS(s) and NH4NO3(aq)
d.Cu2S(s) and NH4NO3(aq)
e.CuS(s), NH3(g), and H2S(g)
Exam 2 Review
Ch. 4, 5 and 7
Page 2 of 4
Chemistry 131
Clark College
14. All the following equations are double-displacement reactions EXCEPT
a.Na2CO3(aq) + H2SO4(aq)  Na2SO4(aq) + H2O(l) + CO2(g).
b. 2NaOH(aq) + H2SO4(aq)  Na2SO4(aq) + 2H2O(l).
c. 2NaOH(aq) + (NH4)2SO4(aq)  Na2SO4(aq) + 2NH3(g) + H2O(l).
d.Na2CO3(aq) + CuSO4(aq)  Na2SO4(aq) + CuCO3(s).
e.Cl2(g) + Na2SO3(s) + H2O(l)  Na2SO4(aq) + 2HCl(aq).
15. Which of the following reactions could be classified both as a precipitation reaction and an acid
base reaction?
a.Cu + 2H2SO4  CuSO4 + SO2 + 2H2O
b.Ba(OH)2 + H2SO4  BaSO4 + 2H2O
c. 2Li + 2H2O  2LiOH + H2
d.CaCO3 + 2HNO3  Ca(NO3)2 + CO2 + H2O
e.POBr3 + 3H2O  H3PO4 + 3HBr
16. The net ionic equation for the reaction of the weak acid phosphoric acid with a dilute solution of
calcium hydroxide to form a precipitate is
a. 6H+(aq) + 2PO43-(aq) + 3Ca2+(aq) + 6OH-(aq)  Ca3(PO4)2(s) + 6H2O(l).
b. 2H+(aq) + 4H2PO4-(aq) + 3Ca2+(aq) + 6OH-(aq)  Ca3(PO4)2(s) + 6H2O(l).
c. 2H3PO4(aq) + 3Ca(OH)2(aq)  Ca3(PO4)2(s) + 6H2O(l).
d. 2H3PO4(aq) + 3Ca2+(aq) + 6OH-(aq)  3Ca2+(aq) + 2PO43-(aq) + 6H2O(l).
e. 2H3PO4(aq) + 3Ca2+(aq) + 6OH-(aq)  Ca3(PO4)2(s) + 6H2O(l).
17. The net ionic equation for the reaction of nitric acid with lithium hydroxide is
a.HNO3(aq) + LiOH(aq)  LiNO3(aq) + H2O(l).
b.HNO3(aq) + LiOH(aq)  Li+(aq) + NO3-(aq) + H2O(l).
c.HNO2(aq) + Li+(aq) + OH-(aq)  Li+(aq) + NO2-(aq) + H2O(l).
d.H+(aq) + NO2-(aq) + Li+(aq) + OH-(aq)  Li+(aq) + NO2-(aq) + H2O(l).
e.H+(aq) + OH-(aq)  H2O(l).
18. How many moles of sulfate ions are there in a 0.20-L solution of 0.030 molar Al2(SO4)3?
a. 0.0030
b. 0.0060
c. 0.012
d. 0.018
e. 0.024
19. What volume of 0.200-molar Na2CO3 (FW = 106) solution contains 53.0 g of Na2CO3?
a. 0.200 L
b. 0.400 L
c. 0.500 L
d. 1.60 L
e. 2.50 L
20. How much 0.54 M NaCl, “physiologic saline,” can be prepared via the dilution of 100 mL of a 6.0 M
NaCl solution?
a. 1.1 L
b.910 mL
c. 90 mL
d.540 mL
e. 1.9 L
Exam 2 Review
Ch. 4, 5 and 7
Page 3 of 4
Chemistry 131
Clark College
21. A student needs to prepare 2.00 L of 0.100 M Na2CO3 (molecular mass = 106). The best procedure
is to weigh out
a. 21.2 g Na2CO3 and add H2O until the final homogeneous solution has a volume of 2.00 L.
b. 10.6 g Na2CO3 and add H2O until the final homogeneous solution has a volume of 2.00 L.
c. 21.2 g Na2CO3 and add 2.00 kg of H2O.
d. 10.6 g Na2CO3 and add 2.00 kg of H2O.
e. 21.2 g Na2CO3 and add 2.00 L of H2O.
Answers
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
d
d
a
d
c
d
b
b
c
b
e
a
c
e
b
e
d
e
e
a
a
Exam 2 Review
Ch. 4, 5 and 7
Page 4 of 4