CHEM 115 Test 2

subject Type Homework Help
subject Pages 6
subject Words 822
subject Authors Bruce E. Bursten, H. Eugene LeMay, Theodore E. Brown

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1) A compound decomposes by a first-order process. If 13% of the compound
decomposes in 60 minutes, the half-life of the compound is ________.
A) 299
B) 20
C) 12
D) -18
E) -5
2) Which of the following expressions is the correct equilibrium-constant expression for
the reaction below?
CO2 (s) + H2O (l) H+ (aq) + HCO3
- (aq)
A) [H+][HCO3
-] / [CO2]
B) [CO2] / [H+][HCO3
-]
C) [H+][HCO3
-] / [CO2][H2O]
D) [CO2][H2O] / [H+][HCO3
-]
E) [H+][HCO3
-]
3) The concentration of carbon monoxide in a sample of air is 6.0 ppm. There are
________ molecules of CO in 1.00 L of this air at 755 torr and 23 oC.
A) 2.5 10-7
B) 1.4 1021
C) 1.9 1018
D) 1.1 1020
E) 1.5 1017
4) Of the following transitions in the Bohr hydrogen atom, the ________ transition
results in the emission of the lowest-energy photon.
A) n = 1 → n = 6
B) n = 6 → n = 1
C) n = 6 → n = 3
D) n = 3 → n = 6
E) n = 1 → n = 4
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5) Which produces the greatest number of ions when one mole dissolves in water?
A) Na3PO4
B) KBr
C) NaMnO4
D) NH4Cl
E) glucose
6) The hybridization of the carbon atom labeled x in the molecule below is ________.
A) sp
B) sp2
C) sp3
D) sp3d
E) sp3d2
7) The Ka of hydrazoic acid (HN3) is 1.9 x 10-5 at 25.0 oC. What is the pH of a 0.15 M
aqueous solution of HN3?
A) 0.82
B) 1.95
C) 5.23
D) 2.77
E) -3.46
8) Which one of the following compounds is an isomer of CH3CH2CH2CH2OH?
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A) CH3CH2CH2OH
B)
C)
D)
E) CH3OH
9) What are the spectator ions in the reaction between Mg(OH)2 (aq) and HCl (aq)?
A) Mg+2 and H+
B) H+ and OH-
C) Mg+2 and Cl-
D) H+ and Cl-
E) OH- only
10) For a given arrangement of ions, the lattice energy decreases as ionic radius
________ and as ionic charge ________.
A) decreases, increases
B) increases, decreases
C) increases, increases
D) decreases, decreases
E) This cannot be predicted.
11) Of the three types of radioactivity characterized by Rutherford, which are particles?
A) ²-rays
B) ±-rays, ²-rays, and ³-rays
C) ³-rays
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D) ±-rays and ³-rays
E) ±-rays and ²-rays
12) Of the following molecules, only ________ is polar.
A) BeCl2
B) BF3
C) CBr4
D) SiH2Cl2
E) Cl2
13) How does lime reduce sulfur dioxide emissions from the burning of coal?
A) It reacts with the sulfur dioxide to form calcium sulfite solid that can be precipitated.
B) It reduces the sulfur dioxide to elemental sulfur that is harmless to the environment.
C) It oxidizes the sulfur dioxide to tetrathionate that is highly water soluble so it can be
scrubbed from the emission gases.
D) It catalyzes the conversion of sulfur dioxide to sulfur trioxide which is much less
volatile and can be removed by condensation.
E) It converts SO2 to solid, elemental sulfur.
14) In which of the following aqueous solutions would you expect AgI to have the
highest solubility?
A) pure water
B) 0.050 M BaI2
C) 0.050 M NaI
D) 0.050 M KI
E) 0.010 M AgNO3
15) Pentacarbonyliron (Fe(CO)5) reacts with phosphorous trifluoride (PF3) and
hydrogen, releasing carbon monoxide:
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Fe(CO)5 + PF3 + H2 → Fe(CO)2(PF3)2(H)2 + CO (not balanced)
The reaction of 5.0 mol of Fe(CO)5 , 8.0 mol of PF3 and 6.0 mol of H2 will release
________ mol of CO.
A) 15
B) 5.0
C) 24
D) 6.0
E) 12
16) What is the order of the reaction with respect to ClO2?
A) 1
B) 0
C) 2
D) 3
E) 4
17) What volume (mL) of sulfur dioxide can be produced by the complete reaction of
3.82 g of calcium sulfite with excess HCl (aq), when the final SO2 pressure is 827 torr
at 44.0 °C?
A) 7.60 x 102
B) 1.39 x 10-4
C) 1.00 x 10-3
D) 0.106
E) 5.78 x 102
18) In counting the electron domains around the central atom in VSEPR theory, a
________ is not included.
A) nonbonding pair of electrons
B) single covalent bond
C) core level electron pair
D) double covalent bond
E) triple covalent bond
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19) Calculate the percentage by mass of nitrogen in PtCl2(NH3)2.
A) 4.67
B) 9.34
C) 9.90
D) 4.95
E) 12.67
20) The molarity of urea in a solution prepared by dissolving 16 g of urea (MW = 60.0
g/mol) in 39 g of H2O is ________ M. The density of the solution is 1.3 g/mL.
A) 0.11
B) 3.7
C) 6.8
D) 6.3
E) 0.16

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