CEM 768 Test

subject Type Homework Help
subject Pages 6
subject Words 772
subject Authors Bruce E. Bursten, H. Eugene LeMay, Theodore E. Brown

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1) The rate constant for a second-order reaction is 0.13 M-1s-1. If the initial
concentration of reactant is 0.26 mol/L, it takes ________ s for the concentration to
decrease to 0.07 mol/L.
A) 0.017
B) 1.4
C) 14
D) 80.
E) 10.
2) Calcium hydride (CaH2) reacts with water to form hydrogen gas:
CaH2 (s) + 2H2O (l) → Ca(OH)2 (aq) + 2H2 (g)
How many grams of CaH2 are needed to generate 48.0 L of H2 gas at a pressure of
0.995 atm and a temperature of 32 °C?
A) 56.8
B) 0.954
C) 161
D) 40.1
E) 80.3
3) The amount of gas that occupies 36.52 L at 68.0 °C and 672 mm Hg is ________
mol.
A) 127
B) 1.15
C) 878
D) 24.4
E) 12.7
4) The dissociation energy of N2 is 941 kJ/mol. The maximum wavelength of light that
has enough energy per photon to dissociate the N2 molecule is ________ nm.
A) 3137
B) 1.27 10-4
C) 1.27 10-7
D) 1.27 105
E) 127
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5) Which ion shown has empty 5s orbitals?
A) Mo2+
B) Y3+
C) Zr4+
D) Nb2+
E) All choices have empty 5s orbitals.
6) Which one of the following vitamins is water soluble?
A) A
B) B
C) K
D) D
E) E
7) Which quantum numbers must be the same for the orbitals that they designate to be
degenerate in a many-electron system?
A) n, l, and ml
B) n only
C) n, l, ml, and ms
D) ms only
E) n and l only
8) Under appropriate conditions, nitrogen and hydrogen undergo a combination reaction
to yield ammonia:
N2 (g) + 3H2 (g) → 2NH3 (g)
If the reaction yield is 87.5%, how many moles of N2 are needed to produce 3.00 mol
of NH3?
A) 0.166
B) 1.00
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C) 1.5
D) 1.71
E) 2.32
9) When a hydrocarbon burns in air, what component of air reacts?
A) oxygen
B) nitrogen
C) carbon dioxide
D) water
E) argon
10) Calculate the pH of a 0.0727 M aqueous sodium cyanide solution at 25.0 oC. Kb for
CN- is 4.9 x 10-10.
A) 9.33
B) 10.00
C) 5.22
D) 1.14
E) 8.78
11) Which of these metals will be oxidized by the ions of cobalt?
A) nickel
B) tin
C) iron
D) copper
E) silver
12) An element in the upper right corner of the periodic table ________.
A) is either a metal or metalloid
B) is definitely a metal
C) is either a metalloid or a nonmetal
D) is definitely a nonmetal
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E) is definitely a metalloid
13) For which one of the following reactions is the value of ΔH°rxn equal to ΔH°f for
the product?
A) H2 (g) + 1/2 O2 (g) → H2O (l)
B) H2 (g) + O2 (g) → H2O2 (l)
C) 2C (s, graphite) + 2H2 (g) → C2H4 (g)
D) 1/2 N2 (g) + O2 (g) → NO2 (g)
E) all of the above
14) The net ionic equation for the reaction between aqueous sulfuric acid and aqueous
sodium hydroxide is ________.
A) H+ (aq) + HSO4
- (aq) + 2OH- (aq) → 2H2O (l) + SO4
2- (aq)
B) H+ (aq) + HSO4
- (aq) + 2Na+ (aq) + 2OH- (aq) → 2H2O (l) + 2Na+ (aq) + SO4
2-(aq)
C) SO4
2- (aq) + 2Na+ (aq) → 2Na+ (aq) + SO4
2-(aq)
D) H+ (aq) + OH- (aq) → H2O( l)
E) 2H+ (aq) + SO4
2- (aq) + 2Na+ (aq) + 2OH- (aq) → 2H2O (l) + 2Na+ (aq) + SO4
2-
(aq)
15) Thermodynamic Quantities for Selected Substances at 298.15 K (25 oC)
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The combustion of hydrogen in the presence of excess oxygen yields water:
2H2(g) + O2(g) --> 2H2O (l)
The value of S o for this reaction is ________ J/K mol.
A) +405.5
B) -405.5
C) -326.3
D) -265.7
E) +265.7
16) Which of the following aqueous solutions will have the highest boiling point?
A) 0.10 m Na2SO4
B) 0.20 m glucose
C) 0.25 m sucrose
D) 0.10 m NaCl
E) 0.10 m SrSO4
17) In the compound, CaNa[Fe(CN)6], what ligands are in the coordination sphere?
A) Ca2+
B) Na+
C) CN-
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D) H2O
E) none of the above
18) The concentration of ozone in a sample of air that has a partial pressure of O3 of
0.53 torr and a total pressure of air of 695 torr is ________ ppm.
A) 7.6 102
B) 0.76
C) 0.076
D) 1.3 10-3
E) 1.3

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