Exam 5: Gases and the Kinetic-Molecular Theory

A compound composed of carbon, hydrogen, and chlorine effuses through a pinhole 0.411 times as fast as neon. Select the correct molecular formula for the compound.

Freon-12, CF₂Cl₂, which has been widely used in air conditioning systems, is considered a threat to the ozone layer in the stratosphere. Calculate the root-mean-square velocity of Freon-12 molecules in the lower stratosphere where the temperature is -65°C.

Calculate the pressure of a helium sample at -207.3°C and 768 mL if it exerts a pressure of 175 kPa at 25.0°C and 925 mL.

Calculate the density in g/L of gaseous SF₆ at 50.0°C and 650. torr.

A sample of the inert gas krypton has its pressure tripled while its temperature remained constant. If the original volume is 12 L, what is the final volume?

A 250.0-mL sample of ammonia, NH₃(g), exerts a pressure of 833 torr at 42.4°C. What mass of ammonia is in the container?

"The rate of effusion of a gas is inversely proportional to the square root of its molar mass" is a statement of ______________________ Law.

Use plots of PV/nRT versus P to show the behavior of an ideal gas and of typical real gases. Label the axes and show their scales.

Select the gas with the highest average kinetic energy per mole at 298 K.

The ideal gas law tends to become inaccurate when

"The volume of an ideal gas is directly proportional to the number of moles of the gas at constant temperature and pressure" is a statement of _____________ Law.

Use the van der Waals equation for real gases to calculate the pressure exerted by 1.00 mole of ammonia at 27°C in a 750-mL container. (a = 4.17 L²atm/mol², b = 0.0371 L/mol)

Which of the following changes will NOT affect the total pressure of gas in a container, assuming all other factors remain constant?

A gas mixture consists of equal masses of methane (molecular weight 16.0) and argon (atomic weight 40.0). If the partial pressure of argon is 200. torr, what is the pressure of methane, in torr?

An unknown liquid is vaporized in a 273-mL flask by immersion in a water bath at 99°C. The barometric pressure is 753 torr. If the mass of the vapor retained in the flask is 1.362 g, what is its molar mass?

"The pressure of an ideal gas is inversely proportional to its volume at constant temperature and number of moles" is a statement of __________________ Law.

State Boyle's Law and illustrate it with a graph, using standard x-y coordinate axes. Be sure to label the axes unambiguously with the correct gas variables.

An oxygen sample of 1.62 L is at 92.3 kPa and 30.0°C. a. What is the pressure of oxygen, in torr? b. What volume would the oxygen occupy if the pressure were 120.0 kPa and the temperature were 0.0°C? c. How many moles of oxygen are in the sample?

Select the gas with the largest root-mean-square molecular speed at 25°C.

Dr. I. M. A. Brightguy adds 0.1727 g of an unknown gas to a 125-mL flask. If Dr. B finds the pressure to be 736 torr at 20.0°C, is the gas likely to be methane, CH₄, nitrogen, N₂, oxygen, O₂, neon, Ne, or argon, Ar?