Question

1. A weather balloon contains 222 L of He gas at 20. °C and 760. mmHg. What is the volume of the balloon when it ascends to an altitude where the temperature is -40. °C and 540. mmHg?

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6. What volume does 12.5 g of Ar gas at a pressure of 1.05 atm and a temperature of 322 K occupy? Would the volume be different if the sample were 12.5 g of He gas under the same conditions?

7. How many moles of gas are contained in a typical human breath that takes in 0.50 L of air at 1.0 atm pressure and 37 °C?

8. A scale model of a blimp rises when it is filled with helium to a volume of 55.0 dm3. When 1.10 mol of He is added to the blimp, the volume is 26.2 dm3. How many more grams of He must be added to make it rise? Assume constant T and P.

9. A sample of gas has a mass of 827 mg. Its volume is 0.270 L at a temperature of 88 oC and a pressure of 975 mmHg. What is the molar mass of the gas?

10.A gas cylinder of 53.7 L volume contains N2 gas at a pressure of 28.2 torr and 26 °C. How many grams of Ne gas must be added to the same cylinder to raise the total pressure to 75.0 torr?

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11.A gaseous mixture made from 6.00 g O2 and 9.00 g CH4 is placed in a 15.0 L vessel at 0°C. What is the partial pressure of each gas, and what is the total pressure in the vessel?

12.Acetylene (C2H2), an important fuel in welding, is produced in the laboratory when calcium carbide (CaC2) reacts with water:

CaC2(s) + 2H2O(l) C2H2(g) + Ca(OH)2(aq)

For a sample of acetylene collected over water, total gas pressure (adjusted to barometric pressure) is 738 torr and the volume is 523 mL. At the temperature of the gas (238 C), the vapor pressure of water is 21 torr. How many grams of acetylene are collected?

13.The safety air bags in automobiles are inflated by nitrogen gas generated by the rapid decomposition of sodium azide, NaN3:

If an air bag has a volume of 36 L and is to be filled with nitrogen gas at a pressure of 1.15 atm at a temperature of 26.0°C, how many grams of NaN3 must be\

decomposed?

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14.One method used in the eighteenth century to generate hydrogen was to pass steam through red-hot steel tubes. The following reaction takes place.

3Fe(s) + 4H2O(g) Fe3O4(s) + 4H2(g)
a. WhatvolumeofhydrogenatSTPcanbeproducedbythereactionof1.00kgof

iron?

b. If 285 g of Fe3O4 are formed, what volume of hydrogen, measured at 20 °C and 1.06 atm, is produced?

15.A mixture of helium (He) and methane (CH4) gases are placed in an effusion apparatus. Calculate the ratio of their effusion rates.

16.Molecular H2 effuses 4 times as fast as gas X at the same temperature. What is the molar mass of gas X?

17.A sample of Xe takes 75 seconds to effuse out of a container. An unknown gas takes 37 seconds to effuse out of the identical container under identical conditions. What is the identity of the diatomic gas?

18.Rank the gases SO2, CO2, and NO2

a) In order of increasing rms speed at 0 oC.
b) In order of increasing density at STP.
c) In order of increasing kinetic energy at STP.

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Answer 1