Exam 10: Gases

Suppose a sample of gas is composed of 100 molecules,with speeds given below. Speed (m/s) Number 200 23 400 42 600 26 800 8 1000 1 According to the kinetic molecular theory,if the absolute temperature of the gas is halved,what is a reasonable estimation of the new distribution of speeds of the molecules?

What is the density of Ar(g)at -11°C and 675 mmHg? (R = 0.08206 L • atm/K • mol,1 atm = 760 mmHg)

A sample of carbon dioxide gas at 125°C and 248 torr occupies a volume of 275 L.What will the gas pressure be if the volume is increased to 321 L at 125°C?

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? (R = 0.08206 L • atm/K • mol,1 atm = 760 torr)

What is the Kelvin temperature at 24°C?

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.

A compound composed of carbon,hydrogen,and chlorine effuses through a pinhole 0.411 times as fast as neon.What is the molecular formula of the compound?

___________ is the formula to determine the density of a substance using the ideal gas law.

A 1.325 g sample of an unknown vapor occupies 368 mL at 114°C and 946 mm Hg.The empirical formula of the compound is NO₂.What is the molecular formula of the compound?

What is the formula which describes the relationship between the volume and temperature at constant pressure and constant number of moles?

_______ _______ states that the volume of a fixed amount of gas maintained at constant pressure is directly proportional to the absolute temperature of a gas.

Starting from the ideal gas equation,derive an equation corresponding to Charles's law,stating all important assumptions or conditions.

State Avogadro's law.

According to the postulates of kinetic molecular theory,the molecules of all gases at a given temperature have the same average speed.

A 7.75-L flask contains 0.482 g of hydrogen gas and 4.98 g of oxygen gas at 65°C.What is the partial pressure of oxygen in the flask?

The Kelvin temperature scale is useful when comparing

Which gas has molecules with the greatest average molecular speed at 25°C?

Gases are compressible and have a density that is much higher than liquids and solids.

What are the units of the constant a in the van der Waals equation?

If a fixed amount of a gas is at a pressure of 2.71 atm and has a volume of 85.3 L at a temperature of 173.4 K,what is the final temperature of the gas if the pressure changes to 1.04 atm in a 105.3 L container?