20. Identify the best Lewis structure for hydrogen cyanide.
21. Which oxide of chlorine exhibits the maximum oxidation state that really exists for
22. Which has the largest radius ?
23. What is the molarity of HCl if 450 mL of 2.3 M HCl is diluted to 1250 mL ?
(A) 0.36 M
(B) 0.50 M
(C) 0.83 M
(D) 1.8 M
24. The first five ionization energies in kJ mol¯1, for a particular
element are shown.
The element is likely to form a ionic compounds in which its charge is
25. Which compound, when dissolved in water, conducts electricity and forms a basic
26. Which pair constitutes a buffer ?
(A) HCl and KCl
(B) NaOH and NaCl
(C) HNO2 and NaNO2
(D) HNO3 and NH4NO3
27. Which oxide dissolves in water to give the strongest acid ?
28. Which is the strongest Bronsted base ?
29. In the reaction F¯ + H2O ---> HF + OH¯ an acid-base conjugate pair
(A) F¯ and H2O
(B) F¯ and OH¯
(C) H2O and HF
(D) F¯ and HF
30. Which is the anhydride of nitric acid ?
31. Which forms a basic aqeous solution ?
32. The best acid for preparing a buffer of pH = 3.2 has a Ka near
(A) 2.0 x 10¯5
(B) 6.0 x 10¯4
(C) 3.2 x 10¯2
(D) 4.0 x 10¯6
33. What is the pH of a 2.0 x 10¯3 M HCl solution ?
34. Consider a solution that contains only one ion, Ag+, Pb2+, or
Hg22+. The solution gave a precipitate with HCl that was insoluble
in hot water but was soluble in dilute ammonia solution. Which ion was present ?
(D) The information is insufficient to identify the ion
35. What is the partial pressure of CO2(g) if Kp for the reaction
is 1.04 atm ?
36. The Ksp values for CaSO4,BaSO4, and Ag2SO4
are 2.0 x 10¯4, 1.5 x 10¯9, and 1.5 x 10¯5
respectively. If 0.010 M Na2SO4 is slowly added to a solution that
contains Ca2+, Ba2+, and Ag+ (each 0.10M), which solid
will precipitate last?
(D) More information is required
37. The Ksp of AgCl is 1.8 x 10¯10. If 10.00 mL of 0.0010 M NaCl
is combined with 20.00 mL of 0.0050 M AgNO3
(A) no reaction occurs
(B) a precipitate forms
(C) an initial precipitate forms which dissolves upon stirring.
(D) the silver ion concentration remainsas 0.005 M.
39. Which value for an equilibrium constant, K, could indicate that the reaction
A(g) + B(g) ---> C(g)
goes nearly to completion?
40. Which is most soluble in a polar solvent?
41. When a liquid is placed in a closed container
(A) evaporation stops
(B) evaporation continues for a time then stops
(C) the vapor pressure above the liquid becomes one atmosphere
(D) evaporation and condensation continue to occur, but at equal rates
42. The sublimination of dry ice is an endothermic process. The energy absorbed is
required to overcome
43. Compared to a 1.0 M aqueous solution of a nonelectrolyte, a 1.0 M solution of an
electrolyte will have a
(A) higher melting point and higher boiling point
(B) higher melting point and lower boiling point
(C) lower melting point and lower boiling point
(D) lower melting point and higher boiling point
44. Which is planar?
45. Calculate DH°f for
4 NH3(g) + 3 O2(g) ---> 2 N2(g) + 6
Given that DH°f for NH3(g) and H2O(g)
are -46.0 and -242 kJ mol¯1 respectively.
(A) -1268 kJ
(B) -196 kJ
(C) +1268 kJ
(D) +196 kJ
46. A white, odorless, crystalline solid melts after about ten seconds in a burner
flame. It is soluble in water and insoluble in carbon tetrachloride. Neither the melt nor
its aqueous solution conducts electricity. We conclude that the substance is
(A) an ionic compound
(B) a non-polar covalent compound
(C) a polar covalent compound
(D) a pure element
47. Given the standard reduction potentials,
Cr3+ + 3e¯ ---> Cr
Pb2+ + 2e¯ ---> Pb
what is the standard potential, E°, for the following reaction?
2 Cr + 3 Pb2+ ---> 2 Cr3+ + 3 Pb
(A) 0.61 V
(B) 0.87 V
(C) 1.09 V
(D) 1.87 V
48. A mixture of 0.10 mol H2 and 0.050 mol O2 are placed in a
bomb calorimeter with a heat capacity of 5.1 x 104 J °C¯1. The
initial temperature is 25.00 °C and the temperature after combustion is 25.56 °C. What
is the DH°f for H2O(l)? (Assume 100%
conversion to water.)
(A) 0.0215 M
(B) 0.0387 M
(C) 0.0644 M
(D) 0.0744 M
61. What is the approximate H-O-H bond angle in H3O+?
62. What hybrid orbitals are used by nitrogen in N2F2?
(D) p only
63. The strongest interaction between atoms listed below is
(A) an instantaneous dipole-dipole interaction
(B) a dipole-dipole interaction
(C) a hydrogen bond
(D) a covalent bond
64. When a 5.0 g sample of an unknown compound is dissolved in 250.0 g of benzene, the
freezing point of benzene decreased 1.4 °C. The freezing point depression constant, Kf,
for benzene is 5.12 °C m¯1. What is the approximate molar mass of the
(A) 290 g mol¯1
(B) 73 g mol¯1
(C) 36 g mol¯1
(D) 140 g mol¯1
Standard reduction potential, E°
Cu2+ (aq) + 2e¯ ---> Cu(s)
Ni2+ (aq) + 2e¯ ---> Ni(s)
When two half-cells are connected using a salt bridge,
(A) a galvanic cell will result in which Cu is the cathode
(B) a galvanic cell will result in which Cu is the anode
(C) an electrolytic cell will result in which Ni is the anode
(D) an electrolytic cell will result in which Ni is the anode
66. What is the maximum number of electrons that can occupy the 5d subshell?
67. For the isoelectronic series below, which species requires the least energy to
remove an outer electron?
68. In aqueous solution, iodide ion (in basic solution) is oxidized by hypochlorite
OCl¯(aq) + I¯(aq) ---> OI¯(aq) + Cl¯(aq)
The rate of formation of hypoiodite, OI¯, is given by the rate law
rate = ( k [OCl¯] [I¯] ) / [OH¯]
What is the overall reaction order for the formation of OI¯?
69. The dissociation of HI molecules, as shown below, occurs at a temperature of 629 K.
The rate constant, k = 3.02 x 10¯5 M¯1 s¯1.
2 HI(g) ---> H2(g) + I2(g)
What is the reaction order?
70. A sodium vapor street lamp emits yellow light with a wavelength of 589 nm. What is
the energy of this light per mole of protons?
(A) 3.37 x 10¯16 kJ mol¯1
(B) 2.35 x 10¯13 kJ mol¯1
(C) 0.201 kJ mol¯1
(D) 203 kJ mol¯1