TakeHome Exam #2
June 10, 2005.
(Due, Monday, June 13)
Please read: Mark the best answer among the given multiple-choices. Then, give your brief explanation next to the question somewhere.
Turn in your answers before class begins on Thursday. Late exam will not be graded. Each answer worth 4 points. You will get 2 points for each
correct answer if you DON’T show your work when is necessary.
1.
A compound that is composed of only carbon and hydrogen contains 85.7%C and 14.3% H
by mass. What is the empirical formula of the compound?
A) C2H4 B) CH4 C) C4H8 D) CH2
2.
A compound contains 40.0%C, 6.71% H, and 53.29% O by mass. The molecular weight of
the compound is 60.05 amu. The molecular formula of this compound is ______.
A)C2H4O2
B)CH2O C)C2H2O4 D)CHO2 E)C2H3O4
3.
How many grams of sodium carbonate contain 1.773x1017 carbon atoms?
A) 9.10x10-5 B) 1.0.x10-5 C) 6.07x10-5 D) 3.02x10-5
4.
When the following equation is balanced, the coefficient of H2S is _____.
H2S + Fe(OH)3  Fe2S3 + H2O
A) 5 B) 4 C) 3 D) 1
5.
A 2.25 g magnesium nitrate, Mg(NO3)2, contains _______ mol of this compound.
A) 38.4 B) 0.0152 C) 0.0261 D) 148.3
6.
The formula weight (molar mass) of potassium dichromate (K2Cr2O7) is ______ amu.
A) 294.18
B) 333.08 C) 107.09 D) 255.08
7.
Lithium and nitrogen react in a combination reaction to produce lithium nitride:
6Li (s) + N2 (g)  2Li3N (s)
In a particular experiment, 3.50 gram samples of each reactant are reacted. The theoretical
yield of lithium nitride is ______ g.
A) 5.85 B) 17.6 C) 8.7 D) 2.93
8.
How many oxygen atoms are contained in 2.74 g of Al2(SO4)3?
A) 7.22x1024 B) 5.79x1022 C) 12 D) 6.02x1023
9.
When the following equation is balanced, the coefficients are________.
A) 2, 3, 2, 3 B) 4, 7, 4, 6
C) 1, 3, 1, 2 D) 1, 1, 1, 1
10.
Which hydrocarbon pair below have identical mass percentage of C?
A) C2H4 and C4H2 B) C3H4 and C3H6 C) C2H4 and C3H6 D) C2H4 and C3H4
11.
The formula of nitrobenzene is C6H5NO2. The molecular weight of this compound is____
amu.
A) 109.10 B) 123.11 C) 107.11 D) 3.06
12.
There are ______ sulfur atoms in 25 molecules of C4H4S2.
A) 1.5x1025
B) 6.02x1023
C) 3.0x1025
D) 50
13.
One mole of _____ contains the largest number of atoms.
A) Al2(SO4)3 B) C10H8 C) S8 D) Na3PO4
14.
The combustion of propane (C3H8) in the presence of excess oxygen yields CO2 and H2O.
C3H8 + 5O2  3CO2 + 4H2O
When 7.3 g of propane burns in the presence of excess oxygen, _____ g of CO2 is
produced.
A) 8.0x102 B) 2.4 C) 22 D) 0.61
15.
How many moles of carbon dioxide are there in 52.06 g of carbon dioxide?
A) 3.13x1023 B) 6.02x1023 C) 1.183
D) 1.183x1023
16.
What is the molarity of a NaOH solution if 28.2 mL of a 0.355 M H2SO4 solution is
required to neutralize a 25.0 mL sample of the NaOH solution?
A) 0.801 B) 0.629 C) 125 D) 0.400
17.
Oxidation cannot occur without______.
A) air B) water C) reduction D) oxygen
18.
Which of the following is an oxidation-reduction reaction?
A) HCl + NaOH  H2O + NaCl
B) Cu + 2AgNO3  2Ag +Cu(NO3)2
C) AgNO3 + HCl  AgCl + HNO3
D) H2CO3 + Ca(NO3)2  2HNO3 +CaCO3
19.
Combining aqueous solutions of BaI2 and K2SO4 affords a precipitate of BaSO4. Which
ion(s) is/are spectator ions in the reaction?
A) Ba2+ only B) K+ and I- C) Ba2+ and SO42- D) SO42- and I-
20.
The net ionic equation for the dissolution of zinc metal in aqueous hydrobromic acid is
______.
A) Zn + 2Br-  ZnBr2 B) Zn +2HBr  ZnBr2 + 2H+ C) 2Zn + H+  2Zn2+ + H2
D) Zn + 2H+  Zn2+ + H2
21.
Which of these metals is the least easily oxidized?
A) Na B) Ag C) Au D) Ca
22.
Which one of the following compounds is insoluble in water?
A) ZnS B) Na2CO3 C) Ag2CO3 D) K2SO4
23.
A tenfold dilution of a sample solution can be obtained by taking ______.
A) 1 part sample and 10 parts solvent B) 99 parts sample and 1 part solvent
parts sample and 1 part solvent D) 1 part sample and 9 parts solvent
C) 10
24.
What is the molarity of a solution prepared by diluting 43.72 mL of 1.005 M aqueous
K2Cr2O7 to 500 mL?
A) 0.870 B) 0.088 C) 0.0115 D) 0.0218
25.
What is the molarity of an aqueous solution containing 75.3 g of glucose (C6H12O6) in 35.5
mL of solution?
A) 11.8 B) 1.85 C) 2.12 D) 3.52
26.
How many grams of CH3OH must be added to water to prepare 150 mL of a solution that is
2.0 M CH3OH?
A) 2.4 B) 4.3 C) 9.6 D) 9.6x103
27.
Mixing 10.0 mL of an aqueous solution with 10.00 mL of water represents a_______.
A) neutralization B) tenfold dilution
C) titration
D) twofold dilution
28.
Which of the following is soluble in water at 25 oC?
A) Fe(OH)2 B) FeCO3 C) Fe(NO3)2 D) FeS