Chem 106 Final Exam
Name___________________________________
08.06.2007
Student Number:_________________________
A-MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1 ) What is the ground state electron configuration for iron(III)?
A) [Ar]3d5
B) [Ar]4s23d3
C) [Ar]4s13d4
D) [Ar]4p5
E) [Ar]4s24p3
2) Which ground state electronic configuration will most readily produce an ion with a charge of 2+?
A) 1s22s22p63s23p4
B) 1s22s22p63s23p63d104s2
C) 1s2s22p63s23p63d104s24p6
D) 1s22s22p63s23p64s1
E) 1s22s22p63s23p63d104s24p2
3) Which of the following occurs for the representative elements going left to right across the period?
A) atomic size increases
B) forces of attraction between electron and nucleus increase because nuclear charge increase
C) electronegativity decreases
D) the outer electrons are held more weakly
E) none of these
4) The first ionization potential for S is lower than the first ionization potential for P because:
A) P is to the right of S on the periodic table
B) Hund's rule is violated
C) ionization potentials decrease across a representative period
D) P has a p3 configuration
E) P is below S on the periodic table
5) Which process is most exothermic, assuming comparison on the basis of per mol of ion?
A) Li → Li+ + eB) O + 2 e- → O2+
C) Li + e- → LiD) F + e- → FE) F → F+ + e6) All of the following oxides are acidic except
A) Cl2O.
B) SO2.
C) MgO.
D) CO2.
7) List in order of increasing size: K+, Se2-, Cl-, Na+, S2A) Na+ < K+ < Cl- < S2- < Se2B) Cl- < S2- < K+ < Na+ < Se2C) S2- < Na+ < Cl- < Se2- < K+
D) Cl- < Se2- < K+ < Na+ < S2E) K+ < Na+ < Cl- < Se2- < S2-
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8) Which of the following bonds is probably the most polar?
A) OH in H2O
B) NH in NH3
C) SeH in SeH2
D) PH in PH3
E) CH in CH4
9) Choose the INCORRECT statement.
A) In a Lewis structure all valence electrons must appear.
B) In a Lewis structure, usually each atom acquires an outer-shell octet of electrons; H has 2 outer shell
electrons.
C) In a Lewis structure, a terminal atom is bonded to two or more atoms.
D) In Lewis structures, most multiple covalent bonds are formed by C, N, O, P, and S.
E) In a Lewis structure, usually all electrons are paired.
10) After drawing the Lewis dot structure of HOClO2, pick the INCORRECT statement of the following. DRAW
THE LEWIS STRUCTURE.
A) The OCl bonds are double bonds.
B) The HO bond is a single bond.
C) The oxygens not bonded to hydrogen have three lone pairs.
D) The oxygen bonded to the hydrogen has two lone pairs.
E) Chlorine has a share of eight electrons.
11) Based on the Lewis structures, which of the following molecules would you expect to exhibit resonance?
DRAW THE LEWIS STRUCTURE OF YOUR CHOICE..
A) OF2
B) LiH
C) CH4
D) HNO2
E) none of these
12) An expanded octet may occur:
A) in families IA, IIA, and IIIA only
B) in the 3rd and 4th period only
C) in all families except IA
D) anywhere except period I and II
E) in the 1st and 2nd period only
13) Which of the following molecules is nonpolar? DRAW THE LEWIS STRUCTURE OF YOUR CHOICE
AND EXPLAIN YOUR ANSWER BRIEFLY.
A) BCl3
B) CHCl3
C) H2O
D) HClO4
E) HCN
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14) What is the molecular shape of BrF5?
A)
B)
C)
D)
E)
square pyramid
square planar
trigonal bipyramid
octahedral
linear
15) The structure of aspirin is given below.
Which set of hybrid orbitals best describes the O-C bond, labeled "a", "b", in aspirin?
A) sp3-sp2
B) sp2-sp2
C) sp3-sp3
D) sp-sp2
16) Which of the following statements concerning the relative energy levels of molecular orbitals for the O2
molecule is INCORRECT?
A) π2p* < σ2p*
B) σ1s* < σ2s
C) σ2s < σ2p
D) σ1s < σ1s*
E) σ2p < π2p
17) If the HCOO- ion is described by using delocalized electrons, why can the oxygen atoms NOT be sp3
hybrids?
A) There must be an unhybridized p orbital to form the pi bond system.
B) The four lobes repel each other too strongly.
C) Molecular orbital theory does not include hybridization.
D) The s orbital must be unhybridized to form the pi bond system.
E) There is no hybridization in systems with delocalized electrons.
18) Under which of the following conditions will vaporization best occur?
A) weak forces between molecules, high kinetic energy, large surface area
B) low kinetic energy, strong molecular forces, large surface area
C) high mass, large surface area, high kinetic energy
D) small surface area, low kinetic energy, low molecular mass
E) high molecular energy, small surface area
19) The phenomenon of supercooling refers to the existence of a metastable:
A) liquid at a temperature below that of its sublimation point
B) liquid at a temperature below that of its freezing point
C) gas at a temperature below that of its critical point
D) liquid at a temperature below that of its critical point
E) two-phase liquid/solid mixture at the freezing point
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20) Which of the following statements is FALSE?
A) London forces exist only between nonpolar molecules.
B) Dipole-dipole forces are most useful when comparing molecules of similar mass.
C) Permanent dipole-dipole forces exist only between polar molecules.
D) London forces are most useful when comparing molecules of widely different masses.
E) Dispersion (London) forces involve displacement of all of the electrons of a molecule.
21) Which probably has the highest boiling point at 1.00 atm pressure?
A) CH3CH2NHCH3
B) (CH3)3N
C) H2NCH2CH2NH2
D) (CH3)2CHNH2
E) CH3CH2CH2NH2
22) The property thjat causes water to have a concave meniscus but mercury to have a convex meniscus is:
A) surface tension
B) vapor pressure
C) critical point
D) sublimation
E) heat of vaporization
23) Given the data below, determine the normal boiling point of COCl2. SHOW YOUR CALCULATIONS.
P1 = 100 mmHg, t1 = -35.6 °C, ΔHvap = 27.4 kJ/mol
A) 278 °C
B) -65.1 °C
C) 5.0 °C
D) -5.0 °C
E) -36.4 °C
24) An aqueous solution containing 1.0 g ephedrine in 20.0 mL solution is said to be: SHOW YOUR
CALCULATIONS.
A) 5.0% ephedrine (mass/vol)
B) 20.0% ephedrine (mass/vol)
C) 0.050% ephedrine (mass/vol)
D) 1.0% ephedrine (mass/vol)
E) 0.50% ephedrine (mass/vol)
25) A magnesium sulfate heptahydrate solution, which is 18.00% by weight in the anhydrous compound, has a
density at 20 °C of 1.20 g/mL. What is the molality of the anhydrous compound in the solution? (Atomic
weights: H = 1.0, O = 16.0, S = 32.1, Mg = 24.3) SHOW YOUR CALCULATIONS.
A) 1.49 M
B) 1.79 M
C) 1.25 M
D) 5.54 M
E) 1.82 M
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26) Which compound is most likely to be soluble in hexane?
A) ethyl alcohol (CH3CH2OH)
B) water
C) chloroform (CHCl3)
D) acetone (CH3COCH3)
E) benzene (C6H12)
27) Which of the following pairs of liquids would form a nonideal solution?
A) CH3CH2CH2OH and CH3CH(OH)CH3
B) CHCl3 and (CH3)2CO
C) H5C6-C6H5 (diphemyl) and C6H6 (benzene)
D) C6H5-CH3 (toluene) and C6H6 (benzene)
28) A handbook lists the aqueous solubility of carbon monoxide at 0 °C and 1 atm CO pressure at 0.0354 mg CO
per mL of solution. What would be the molarity of CO in water at the normal partial pressure of CO in air of
0.00036 atm. SHOW YOUR CALCULATIONS.
A) 2.9 × 10-4 M
B) 1.6 × 10-3 M
C) 1.3 × 10-5 M
D) 3.2 × 10-3 M
E) 4.5 × 10-7 M
29) The vapor pressures of pure propyl alcohol and isopropyl alcohol are 21. 0 mmHg and 45. 2 mmHg,
respectively, at 25oC. What is the composition of the vapor in equilibrium with a propyl alcohol - isopropyl
alcohol solution in which the mole fraction of propyl alcohol is 0.250? SHOW YOUR CALCULATIONS.
A) xiso = 0.317, xprop = 0.683
B) xiso = 0.750, xprop = 0.250
C) xiso = 0.866, xprop = 0.134
D) xiso = 0.512, xprop = 0.488
30) An unknown compound is composed of 65.44% C, 29.07% O and 5.49% H. A sample weighing 5.34 g, when
dissolved in 60.00 g H2O lowers the freezing point to -0.600 °C. What is the molecular formula of the
compound? (Kf for water = 1.86 °C/m; C = 12.0, O = 16.0, H = 1.0 g/mol). SHOW YOUR CALCULATIONS.
A) CHO
B) C5H5O5
C) C3H3O
D) C15H15O5
E) none of these
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31) What is the value for Kc if [CO] = 0.025, [H2] = 0.013 and [CH3OH] = 0.0028 for the following reaction?
SHOW YOUR CALCULATIONS.
CH3OH(g) ⇌ CO(g) + 2 H2(g)
A) 9.1 × 10-7
B) 0.12
C) 8.6
D) 1.5 × 10-3
E) 6.6 × 102
32) For the reaction: H2(g) + I2(g) ⇔ 2 HI(g), Kc = 92.0 When equilibrium concentrations of HI and I2 are
[HI] = 0.115 M and [I2] = 0.250 M, the equilibrium concentration of [H2] is: SHOW YOUR
CALCULATIONS.
A) 0.135 M
B) 5.00 × 10-3 M
C) 9.56 M
D) 5.75 × 10-4 M
E) 1.74 × 103 M
33) For the following chemical equilibrium, Kp = 4.6 × 10-14 at 25 °C, find the value of Kc for this reaction at
25°C. SHOW YOUR CALCULATIONS.
2 Cl2(g) + 2 H2O(g) ⇔ 4 HCl(g) + O2(g)
A) Kc = 2.2 × 10-14
B) Kc = 4.6 × 10-14
C) Kc = 1.9 × 10-15
D) Kc = 9.4 × 10-14
E) Kc = 1.1 × 10-12
34) For the reaction CO(g) + 3 H2(g) → H2O(g) + CH4(g), Kc = 190 at 1000 K. If a vessel is filled with these gases
such that the initial concentrations are [CO] = 0.036M, [H2] = 0.045, [H2O] = 0.020, and [CH4] = 0.031, in
which direction will a reaction occur and why? SHOW YOUR CALCULATIONS.
A) toward products because Q = 4.1
B) it is at equilibrium
C) toward reactants because Q = 0.24
D) toward products because Q = 0.38
E) toward reactants because Q = 61
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35) Which factor influences the value of the equilibrium constant for a reversible reaction?
A) removing product
B) addition of a catalyst
C) raising the temperature
D) removing reactant
E) all of these
36) For the reaction: CH4(g) + 2 H2O(g) ⇔ CO2(g) + 4 H2(g) ΔH° = +190 kJ when CH4 is added:
A)
B)
C)
D)
E)
the ΔH° increases.
the reaction reacts to the left.
the temperature increases.
the reaction reacts to the right.
there is no change.
37) For the reaction: CH4(g) + 2 H2O(g) ⇔ CO2(g) + 4 H2(g) ΔH° = +190 kJ raise the temperature to 1200 K:
A)
B)
C)
D)
E)
the reaction reacts to the left.
the reaction reacts to the right.
the ΔH° increases.
the temperature increases.
there is no change.
38) Which of the following isoelectronic species has the largest radius?
B) Mg2+
C) Ne
A) F-
D) O2-
E) Na+
39) Consider the following chemical reaction at equilibrium:
2 Cl2(g) + 2 H2O(g) ⇔ 4 HCl(g) + O2(g)
This equilibrium can be shifted to the right by:
A) removing H2O(g) from the mixture.
B) adding Ne(g) to the mixture.
C) adding more O2(g) to the mixture.
D) increasing the volume of the mixture.
E) decreasing the volume of the mixture.
40) Consider the following equation:
N2O4(g) ⇔ 2 NO2(g) Kc = 5.8 × 10-3
If the initial concentration of N2O4(g) = 0.040 M and the initial concentration of NO2(g) is 0 M, what is the
equilibrium concentration of N2O4(g)? SHOW YOUR CALCULATIONS.
A) 1.7 × 10-2 M
B) 2.6 × 10-2 M
C) 1.9 × 10-2 M
D) 2.3 × 10-6 M
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