CHEM 826 Test 1

subject Type Homework Help
subject Pages 6
subject Words 869
subject Authors Bruce E. Bursten, H. Eugene LeMay, Theodore E. Brown

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1) All atoms of a given element have the same ________.
A) mass number
B) number of nucleons
C) atomic mass
D) number of neutrons
E) atomic number
2) Thermodynamic Quantities for Selected Substances at 298.15 K (25 oC)
The value of S o for the decomposition of phosphorous trichloride into its constituent
elements,
2PCl3 (g) --> P2 (g) + 3Cl2( g)
is ________ J/K mol.
A) -311.7
B) +311.7
C) +263.6
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D) +129.4
E) -129.4
3) In a Torricelli barometer, a pressure of one atmosphere supports a 760 mm column of
mercury. If the original tube containing the mercury is replaced with a tube having
twice the diameter of the original, the height of the mercury column at one atmosphere
pressure is ________ mm.
A) 380
B) 760
C) 1.52 x 103
D) 4.78 x 103
E) 121
4) The element lithium is in a group known as the _______.
A) transition metals
B) alkaline earth metals
C) noble gases
D) halogens
E) alkali metals
5) Carbon dioxide contributes to atmospheric warming by ________.
A) absorbing incoming radiation from the sun and converting it to heat
B) absorbing radiation emitted from the surface of the earth preventing its loss to space
C) undergoing exothermic reactions extensively in the atmosphere
D) increasing the index of refraction of the atmosphere so that infrared radiation from
the sun is refracted to the surface of the earth where it is converted to heat
E) reducing the concentration of CO in the atmosphere
6) Of the following elements, ________ is the least easily oxidized.
zinc
iron
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hydrogen
aluminum
lead
A) zinc
B) iron
C) hydrogen
D) aluminum
E) lead
7) When the following equation is balanced, the coefficient of HCl is ________.
CaCO3 (s) + HCl (aq) → CaCl2 (aq) + CO2 (g) + H2O (l)
A) 1
B) 2
C) 3
D) 4
E) 0
8) ΔH for the reaction:
IF5 (g) → IF3 (g) + F2 (g)
is ________ kJ, give the data below.
IF (g) + F2 (g) → IF3 (g) ΔH = -390 kJ
IF (g) + 2F2 (g) → IF5 (g) ΔH = -745 kJ
A) +355
B) -1135
C) +1135
D) +35
E) -35
9) Which of the following substances is more likely to dissolve in CH3OH?
A) CCl4
B) Kr
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C) N2
D) CH3CH2OH
E) H2
10) ________ significant figures should be retained in the result of the following
calculation.
A) 1
B) 2
C) 3
D) 4
E) 5
11) Which one of the following forms of radiation can penetrate the deepest into body
tissue?
A) alpha
B) beta
C) gamma
D) positron
E) proton
12) For the reaction
C2H6 (g) --> C2H4 (g) + H2 (g)
H o is +137 kJ/mol and S o is +120 J/K mol. This reaction is ________.
A) spontaneous at all temperatures
B) spontaneous only at high temperature
C) spontaneous only at low temperature
D) nonspontaneous at all temperatures
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13) The Ka of hypochlorous acid (HClO) is 3.0 x 10-8 at 25 oC. What is the percent
ionization of hypochlorous acid in a 0.015 M aqueous solution of HClO at 25 oC?
A) 4.5 x 10-8
B) 14
C) 2.1 x 10-5
D) 0.14
E) 1.4 x 10-3
14) The ________ quantum number defines the shape of an orbital.
A) spin
B) magnetic
C) principal
D) angular momentum
E) psi
15) The 4d subshell in the ground state of atomic xenon contains ________ electrons.
A) 2
B) 6
C) 8
D) 10
E) 36
16) Given the following reaction:
CO (g) + 2 H2(g) CH3OH (g)
In an experiment, 0.42 mol of CO and 0.42 mol of H2 were placed in a 1.00-L reaction
vessel. At equilibrium, there were 0.29 mol of CO remaining. Keq at the temperature of
the experiment is ________.
A) 2.80
B) 0.357
C) 14.5
D) 17.5
E) none of the above
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17) According to valence bond theory, which orbitals overlap in the formation of the
bond in HCl?
A) 1s on H and 2p on Cl
B) 2s on H and 3p on Cl
C) 1s on H and 3s on Cl
D) 1s on H and 3p on Cl
E) 1s on H and 4p on Cl
18) The Ka of acetic acid is 1.76 x 10-5. The pH of a buffer prepared by combining 15.0
mL of 1.00 M potassium acetate and 50.0 mL of 1.00 M acetic acid is ________.
A) 1.705
B) 0.851
C) 3.406
D) 4.232
E) 2.383
19) Of the following, a 0.1 M aqueous solution of ________ will have the highest
freezing point.
A) NaCl
B) Al(NO3)3
C) K2CrO4
D) Na2SO4
E) sucrose
20) One significant difference between gases and liquids is that ________.
A) a gas is made up of molecules
B) a gas expands to fill its container
C) a gas may consist of both elements and compounds
D) gases are always mixtures
E) All of the above answers are correct.

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