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10
10
10
10
15
15
15
15
: 100 total possible
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Chemistry 1201 Section 4
Spring 1999
Professor Russo
Exam #8
Type of exam: Take-home. You can work with anyone on this exam, including me! You should know how to
do these problems, though. You will probably see similar problems again.
Due: Tuesday, April 20, at the beginning of class.
100 points. After this exam, you will have had 800 total points. If you have more than 700, you can even
stop taking exams (except the final, of course!).
Show your work neatly. We will not grade papers that just show an answer, nor can we assign partial
credit if we don't see the work.
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Question #1. (BLB 3.44) Determine the empirical formula of a compound that contains (by
mass) 10.4% C, 27.8% S and 61.7% Cl.
Worth 10 points
_________________________
show empirical formula here
Question #2. (BLB 3.48) Determine the molecular formula of nicotine, which contains
74.1% C, 8.6% H and 17.3% N by mass. Nicotine has a molar mass of 160  5 g.
Worth 10 points
_________________________
show molecular formula here
Chem 1201 Sec. 4
Exam #8
Page 1
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Question #3. (BLB 3.62) Many antacids contain aluminum hydroxide as the active
ingredient. How many grams of aluminum hydroxide react fully with 2.50 g of hydrochloric
acid to make water and aluminum chloride?
Worth 10 points
_________________________
grams of aluminum hydroxide
Question #4. (based BLB 3.80b) Al2O3 occurs in nature as the mineral corundum. Noted for
its hardness, corundum has a density of 3.97 g/cm3. How many oxygen atoms are there in 1.00
cubic inch of corundum? Express your answer in moles.
Worth 10 points
____________________________
moles of oxygen atoms
Chem 1201 Sec. 4
Exam #8
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Question #5. (based on BLB 3.83) Pyridine (C5H5N) is a substance that stinks to high
heaven! It is surely among the foulest smelling of commonly used, volatile organic solvents.
Its smell resembles really rotten garbage. To remove pyridine from the air, you might try
adsorbing (adsorbing is like absorbing, except on the surface only) it on the surface of a finely
ground metal oxide, such as ZnO. Suppose that 5.00 g of finely divided zinc oxide is found to
adsorb 0.068 g of pyridine. Further, suppose that the specific surface area (surface area per
gram) of the ZnO powder is 48 m2/g (i.e., just one gram of powder has a surface area
equivalent to the floor of a typical bedroom). Compute the average surface area per adsorbed
pyridine molecule. Express your answer in nm2/pyridine molecule.
Worth 15 points
___________________________
nm2/pyridine molecule
Chem 1201 Sec. 4
Exam #8
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Question #6. (BLB 3.72) Solutions of sulfuric acid and lead(II)acetate react to form solid lead
sulfate and a solution of acetic acid. If 10.0 g of sulfuric acid and 10.0 g of lead acetate are
mixed, calculate the number of grams of sulfuric acid, lead acetate, lead sulfate and acetic acid
present in the mixture after the reaction is complete. (Note: you can find the various ions
listed on the inside back cover of your book; use the index to find sulfuric acid).
Worth 15 points
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g H2SO4
Chem 1201 Sec. 4
____________
g Pb(C2H3O2)2
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g PbSO4
Exam #8
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g HC2H3O2
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Question 7. (BLB 3.70) How many grams of carbon dioxide can form when a mixture of
1.93 g ethylene (C2H4) and 3.75 g of oxygen is ignited, assuming complete combustion to form
carbon dioxide and water?
Worth 15 points
_____________________
grams of carbon dioxide
Chem 1201 Sec. 4
Exam #8
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Question 8. (based on BLB 10.5) Suppose a woman is ocean scuba diving in 24 feet of water
(density = 1 g/mL) on a day when the ambient atmospheric pressure at the surface of the ocean
is 740 mm Hg. What is the total pressure on this diver? Express your answer in atmospheres
and also in pounds per square inch.
Worth 15 points
_________________________
pressure in atm
Chem 1201 Sec. 4
_______________________
pressure in lbs/in2
Exam #8
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