Exam 5: Gases and the Kinetic-Molecular Theory

Given that pressure has dimensions of force * area; that force has dimensions of mass * acceleration; and that the S.I. unit of pressure is the pascal, what is 1 pascal in terms of S.I. base units?

What is the density of carbon dioxide gas at -25.2 $\degree$ C and 98.0 kPa?

For a gas obeying Boyle's Law, a plot of V versus 1/P will give a straight line passing through the origin.

For real gases, PV < nRT, always.

Briefly state the conditions corresponding to STP (standard temperature and pressure).

A sample container of carbon monoxide occupies a volume of 435 mL at a pressure of 785 torr and a temperature of 298 K. What would its temperature be if the volume were changed to 265 mL at a pressure of 785 torr?

Calculate the temperature of an argon sample at 55.4 kPa and 18.6 L if it occupies 25.8 L at 75.0 $\degree$ C and 41.1 kPa.

A 3.0-L sample of helium was placed in a container fitted with a porous membrane. Half of the helium effused through the membrane in 24 hours. A 3.0-L sample of oxygen was placed in an identical container. How many hours will it take for half of the oxygen to effuse through the membrane?

A sample of an ideal gas has its volume doubled while its temperature remains constant. If the original pressure was 100 torr, what is the new pressure?

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

When a closed-ended manometer is used for pressure measurements, and the closed end is under vacuum, the level of manometer liquid in the closed arm can never be lower than that in the other arm.

Hydrogen peroxide was catalytically decomposed and 75.3 mL of oxygen gas was collected over water at 25 $\degree$ C and 742 torr. What mass of oxygen was collected? (P_water = 24 torr at 25 $\degree$ C)

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.

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 $\degree$ C.

The volume of a single molecule of water is 2.99 *10¯²³ mL. For a sample of gaseous water at 1.00 atm and 150 $\degree$ C, what fraction of the container's volume is occupied by the molecules themselves?

"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.

A sample of ammonia gas at 65.5 $\degree$ C and 524 torr has a volume of 15.31 L. What is its volume when the temperature is -15.8 $\degree$ C and its pressure is 524 torr?

Assuming ideal behavior, what is the density of argon gas at STP, in g/L?

A weather balloon was initially at a pressure of 0.950 atm, and its volume was 35.0 L. The pressure decreased to 0.750 atm, without loss of gas or change in temperature. What was the change in the volume?

Magnesium metal (0.100 mol) and a volume of aqueous hydrochloric acid that contains 0.500 mol of HCl are combined and react to completion. How many liters of hydrogen gas, measured at STP, are produced? Mg(s) + 2HCl(aq) $\rightarrow$ MgCl₂(aq) + H₂(g)