CHEMISTRY 102
PRACTICE FINAL EXAM
Spring 2005
Some equations that may be helpful:
E = E0 -
0.0592
log Q
n
ΔG 0 = -RTlnK
(R = 8.314 J/mol • K)
ΔG = -nFE
You will also be given a table of standard reduction half-reaction potentials.
1.
Calculate the molar solubility of magnesium hydroxide in a solution that is buffered at pH = 9.0.
Ksp for Mg(OH)2 is 1.5 x 10-11.
(a) 1.5 x 107 (b) 1.5 x 10-1 (c) 1.5 x 10-3 (d) 3.9 x 10-1 (e) 1.5 x 10-7
2.
When equal volumes of the solutions are mixed, precipitation should occur for:
(a) 2 x 10-6 M Ag+ + 2 x 10-5 M Cl(b) 2 x 10-5 M Sr2+ + 2 x 10-6 M CO32(c) 2 x 10-5 M Mg2+ + 2 x 10-4 M CO32-
3.
4.
5.
(d) 2 x 10-7 M Ag+ + 2 x 10-7 M I(e) 2 x 10-4 M Pb2+ + 2 x 10-4 M ICalculate the pH of 0.040 M NH4Cl.
(a) 4.63 (b) 3.44
(c) 5.04
(d) 5.16
(e) 5.33
What is the molecular formula for heptane?
(a) C7H14
(b) C7H12
(c) C9H18
(d) C7H16
(e) C9H20
Solid Na2SO4 is added to a solution that is 0.25 M in both Sr2+ and Pb2+. Assuming no
volume change, what will be the [Pb2+] at the point at which SrSO4 just begins to
precipitate at 25°C? Ksp for SrSO4 = 2.8 x 10–7 and for PbSO4 = 1.8 x 10–8.
(a) 0.24 M (b) 0.16 M (c) 0.30 M (d) 0.016 M (e) 0.04 M
6. If 100. mL of 0.060 M NaOH is added to 100. mL of solution which is 0.10 M in CH3COOH
and 0.10 M in NaCH3COO, what will be the pH of the new solution?
(a) 5.7 (b) 5.3 (c) 4.7 (d) 4.1 (e) 2.8
7.
The molar solubility of a metal carbonate, MCO3, is 9.0 x 10–5 M at 25°C. What is the
solubility product constant for the metal carbonate?
(a) 1.2 x 10–8
(b) 8.1 x 10–9
(c) 5.3 x 10–12
(d) 4.0 x 10–15
(e) 6.7 x 10–11
8. If 100 mL of 0.40 M NaOH solution is added to 100 mL of solution which is 0.15 M in CH3COOH
and 0.10 M in NaCH3COO, what will the pH of the new solution be?
(a) 13.10
(b) 13.60
(c) 9.47
(d) 12.88
(e) 14.00
9.
What mass of CaF2 is contained in 1.0 liter of saturated solution? Ksp = 3.9 x 10–11.
(a) 0.017 g
(b) 0.00033 g
(c) 0.00021 g
(d) 0.013 g
(e) 0.051 g
10. Calculate the pH of a saturated aqueous solution of Co(OH)2. Ksp is 2.5 x 10–16.
(a) 8.15 (b) 8.90
(c) 9.10
(d) 9.20
(e) 9.40
11. If enough base is added to a solution to cause the pH to increase from 7.5 to 8.5, the ____.
© 2004 PECK Fin. Rev. page 2
(a) [OH–] increases by a factor of 10
(c) [OH–] increases by 1 M
12.
13.
14.
15.
(b) [H3O+] increases by a factor of 10
(d) [H3O+] increases by 1 M
(e) [OH–] increases by a factor of 8.5/7.5
PbBr2 would be least soluble at 25°C in _____.
(a) pure water
(b) 0.01 M CaBr2
(c) 0.1 M HBr
(d) 0.01 M Pb(NO3)2
(e) 0.1 M Pb(NO3)2
Which one of the following statements about the oxidizing strength of the group IB metals
(Cu, Ag, and Au) is true?
(a) Cu is easier to oxidize than Au.
(b) Au is easier to oxidize than Ag.
(c) Ag is easier to oxidize than Cu.
(d) Au is easier to oxidize than Cu.
(e) Nothing can be decided about this from a table of electrode potentials.
Calculate the amount of time (in hours) it would take to electroplate 25.0 g of Pt from a
solution of Pt4+ at a current of 25.0 amperes if the efficiency of the production of Pt is
95.0% (that is, 5.0% of the current is used up in undesirable side-reactions).
(a) 2.32
(b) 2.20
(c) 0.522
(d) 1.74
(e) 1.65
Given the following standard electrode potentials:
Half Reactions
Eo
O2(g) + 4H+ + 4e2H2O
+ 1.23 V
2CO2(g) + 2H+ + 2e(COOH)2 -0.49 V
Which response contains all the true statements and no others? (Assume all species are
present under standard electrochemical conditions)
(1) H2O will spontaneously oxidize (COOH)2 to form CO2.
(2) O2(g) will spontaneously oxidize (COOH)2 to form CO2.
(3) (COOH)2 will spontaneously reduce O2(g) to form H2O.
(4) H+ will spontaneously reduce (COOH)2 to form CO2.
16.
17.
18.
19.
(5) CO2 will spontaneously oxidize H2O to form O2(g).
(a) 2,4,5 (b) 1,3,4 (c) 2,3 (d) 1,4 (e) 3
What is ∆G0 at 25°C for the reaction below? (F = 96,500 J/V•mol e–)
Cu2+ + Cd → Cu + Cd2+
(a) –71.1 kJ
(b) –143 kJ (c) 597 kJ
(d) 193 kJ
(e) +71.1 kJ
The geometric arrangement of sp3d2 orbitals is:
(a) linear (b) trigonal planar (c) tetrahedral (d) trigonal bipyramidal (e) octahedral
The number of donor atoms to which an acceptor metal ion is bonded in a complex
species is called the _____ number of the metal ion.
(a) oxidation
(b) ligand
(c) coordination
(d) donor
(e) chelating
Which of the following compounds could exist as cis /trans-isomers?
(b) CH 3CH CH2
(c) (CH3) 2C CH2
(a) H2C CH2
(d) CH3CH CHCH 3
(e) CH2 C
CH2 CH3
CH3
20.
Four of the names correctly name the formula to its left. One name
does not?
Formula
Name
does not. Which one
© 2004 PECK Fin. Rev. page 3
(a) [SnCl6]2–
hexachlorostannate(V) ion
(b) K[Cr(NH3)2Cl4]
potassium diamminetetrachlorochromate(III)
(c) [Co(NH3)4(OH2)I]SO4
tetraammineaquaiodocobalt(III) sulfate
(d) [Ni(NH3)4]
tetraamminenickel(0)
(e) Ca[PtCl4]
calcium tetrachloroplatinate(II)
21. The equilibrium constant, at 25°C, for the balanced reaction shown below is
1.34 x 1057. What is E0 for this reaction?
4Tl + 3XO2– + 12H+ → 4Tl3+ + 3 X– + 6H2O
(a) 0.76 V
(b) 0.90 V
(c) 0.28 V
(d) 0.22 V
(e) 1.03 V
22.
What is the correct name for the compound below?
Br
23.
24.
25.
26.
27.
28.
Br H
H
C
C
C
H
H
H
H
(a) 1,1-dibromoethane
(b) 1,2-dibromopentane
(c) 1,2-dibromopropane
(d) 1,1-dibromopropane
(e) None of these answers is correct.
NO reacts with chlorine in a gas phase reaction to form nitrosyl chloride, NOCl. From
the following experimental data, determine the form of the equation that describes the
relationship of reaction rate to initial concentrations of reactants.
2NO + Cl2 →2NOCl
Run
Initial [NO]
Initial [Cl2]
Initial Rate of
Formation of NOCl
1
0.50 M
0.50 M
1.14 M/hr
2
1.00 M
1.00 M
9.12 M/hr
3
1.00 M
0.50 M
4.56 M/hr
(a) Rate = k[NO]
(b) Rate = k[NO][Cl2]
(c) Rate = k[NO]2
(d) Rate = k[NO]2[Cl2]
(e) Rate = k[NO]2[Cl2]2
The pH of a solution of hydrochloric acid is 2.80. What is the molarity of the acid?
(a) 6.3 x 10–3 M
(b) 4.2 x 10–3 M
(c) 1.6 x 10–3 M
(d) 6.3 x 10–2 M
(e) 4.2 x 10–2 M
If 100 mL of 0.040 M NaOH solution is added to 100 mL of solution which is 0.10 M in
CH3COOH and 0.10 M in NaCH3COO, what will the pH of the new solution be?
(a) 4.74
(b) 4.81
(c) 4.89
(d) 5.00
(e) 5.11
Evaluate the hydrolysis constant for sodium cyanate, NaOCN.
(a) 3.7 x 10–12
(b) 6.4 x 10–9
(c) 2.9 x 10–11
(d) 4.0 x 10–10
(e) 6.8 x 10–10
If 50.00 mL of 0.1000 M NaOH is titrated with 0.1000 M HCl, what is the pH of the
solution after 30.00 mL of HCl solution has been added?
(a) 13.00
(b) 12.40
(c) 12.60
(d) 12.00
(e) none of these
–5
At 25°C, 1.4 x 10 mole of M(OH)2 dissolves to give 1.0 liter of saturated aqueous
solution. What is the solubility product for M(OH)2?
(a) 1.7 x 10–5
(b) 2.9 x 10–10
(c) 1.1 x 10–14
(d) 5.8 x 10–15
(e) 4.1 x 10–12
© 2004 PECK Fin. Rev. page 4
29.
30.
What is the cell potential for a cell constructed by immersing a strip of copper in a 1.0 M
CuSO4 solution and a strip of tin in a 1.0 M SnSO4 solution and completing the circuit
by a wire and a salt bridge?
(a) –0.19 V
(b) +0.19 V
(c) –0.48 V
(d) +0.48 V
Given the following standard electrode potentials:
Half-Reaction___________
E0___
O2(g) + 4H+ + 4e– → 2H2O
+1.23 V
2 CO2(g) + 2H+ + 2e– → (COOH)2
–0.49 V
Which response contains all the true statements and no others? (Assume all species are
present under standard electrochemical conditions.)
I.
H2O will spontaneously oxidize (COOH)2 to form CO2.
II.
O2(g) will spontaneously oxidize (COOH)2 to form CO2.
III.
(COOH)2 will spontaneously reduce O2(g) to form H2O.
IV.
H+ will spontaneously reduce (COOH)2 to form CO2.
V.
CO2 will spontaneously oxidize H2O to form O2(g).
(a) II, IV, and V
(b) I, III, and IV (c) II and III (d) I and IV (e) III and V
ANSERS: (1) b, (2) d, (3) e, (4) d, (5) d, (6) b, (7) b, (8) a, (9) a, (10) b, (11) a, (12) c, (13) a,
(14) c, (15) c, (16) b, (17) e, (18) c, (19) d, (20) a, (21) c, (22) d, (23) d, (24) c, (25) e, (26) c,
(27) b, (28) c, (29) d, (30) c.