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SOLUTIONS - CHAPTER 11 Problems
NOTE: The final exam is Thursday, December 8 th, from 2:15pm to 4:45pm. The final
exam is comprehensive (it covers material from Chapters 1-11 of Burdge). For Chapters
10 and 11 you are only responsible for the material covered in the lecture.
1) (Burdge, 11.30) At 46. C a sample of ammonia gas exerts a pressure of 5.3 atm.
What is the pressure when the volume of the gas is reduced to one-fourth of the original
value at the same temperature?
2) (Burdge, 11.32) A sample of air occupies 3.8 L when the pressure is 1.2 atm.
Assuming constant temperature
a) What volume does it occupy for p = 6.6 atm?
b) What pressure is required to compress it to 0.075 L?
3) (Burdge, 11.42) A sample of nitrogen in a 4.5 L container at a temperature of 27. C
exerts a pressure of 4.1 atm. Calculate the number of moles of gas in the sample.
4) 0.451 moles of an ideal gas is confined in a tank of volume V = 2.63 L at a
temperature T = 25.0 C. What is the pressure of the gas in atm and in torr?
5) (Burdge, 11.48) An ideal gas originally at 0.85 atm and 66. C was allowed to expand
until its final volume, pressure, and temperature were 94. mL, 0.60 atm, and 45. C.
What was the initial volume?
6) (Burdge, 11.52) At STP, 0.280 L of a gas weighs 0.400 g. Calculate the molar mass of
the gas.
7) (Burdge, 11.56) A 2.10 L vessel contains 4.65 g of a gas at 1.00 atm and 27.0 C.
a) Calculate the density of the gas in g/L.
b) What is the molar mass of the gas?
8) (Burdge, 11.58) A certain anesthetic contains 64.9 % C, 13.5 % H, and 21.6 % O by
mass. At 120. C and 750. mm Hg, 1.00 L of the gaseous compound weighs 2.30 g.
What is the molecular formula of the compound?
9) (Burdge, 11.70) A mixture of gases contains 0.31 mol CH4, 0.25 mol C2H6, and 0.29
mol C3H8. The total pressure is 1.50 atm. Calculate the partial pressures of each gas.
10) A gas mixture contains helium (He) and argon (Ar). The density of the gas,
measured at T = 20.0 C and p = 766. torr, is D = 0.458 g/L. Based on this information,
and assuming the ideal gas law applies, find the mol fraction helium in the gas mixture.
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11) (Burdge, 11.82) When coal is burned the sulfur present is converted into sulfur
dioxide (SO2), which is partly responsible for acid rain.
S(s) + O2(g)  SO2(g)
If 3.15 kg of S reacts with oxygen, calculate the volume of SO2 gas (in mL) formed at
30.5 C and 1.04 atm.
12) (Burdge, 11.88) Calculate the mass, in grams of hydrogen chloride produced when
5.6 L of molecular hydrogen (H2), measured at STP, reacts with an excess of chlorine gas
(Cl2).
13) (Burdge, 11.8) Compare the root mean square speed of O2 and UF6 at T = 65. C.
14) At what temperature will the rms speed of a nitrogen molecule (N2) be urms = 500.
m/s? Give your answer in both K and C.
15) (Burdge, 11.14) The average distance traveled by a molecule between successive
collision is called the mean free path. For a given amount of gas, how does the mean free
path depend on the following: a) density, b) temperature, at constant volume, c) pressure,
at constant temperature, d) volume, at constant temperature e) size of the gas molecules
16) Use the data in Table 11.5 to calculate the pressure exerted by 2.50 mol of CO2
confined in a volume of 5.00 L at 450. K. Compare the pressure to that calculated by the
ideal gas law. Which pressure is correct?
17) (Burdge, 11.107) Consider the following apparatus. Calculate the partial pressures of
helium and neon after the stopcock is opened. The temperature remains constant at 16.
C.
18) (Burdge, 11.135) Nitrogen forms several gaseous oxides. One of them has a density
of 1.33 g/L when measured at 764. mm Hg and 150. C. What is the formula of the
compound?
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