The local news in an urban area reports an ozone concentration of 110 ppb on a hot summer day. What is the concentration of ozone in units of ppm and volume percent? How many ozone molecules are inhaled in one breath that contains 3.3 X 10$^{-2}$ moles of air?

Which gas in each of the following pairs diffuses more rapidly, and what are the relative rates of diffusion?

(a) Kr and O$_2$

(b) N$_2$ and acetylene (C$_2$H$_2$)

A special gas mixture used in bacterial growth chambers contains 1.00% by weight CO$_2$ and 99.0% O$_2$. What is the partial pressure in atmospheres of each gas at a total pressure of 0.977 atm?

At an underwater depth of 250 ft, the pressure is 8.38 atm. What should the mole fraction of oxygen in the diving gas be for the partial pressure of oxygen in the gas to be 0.21 atm, the same as in air at 1.0 atm?

Nitrox is a gas mixture used by scuba divers to prevent nitrogen narcosis, a loss of mental and physical function, caused by increased levels of dissolved nitrogen in the blood. The mole fraction of O$_2$ is 0.36, and the mole fraction of N$_2$ is 0.64 in a 10.0 L tank with a pressure of 50 atm at 25 degree celcius.

(a) Calculate the partial pressure of O$_2$ and N$_2$.

(b) Calculate the number of moles of O$_2$ and N$_2$.

Propane gas (C$_3$H$_8$) is often used as a fuel in rural areas. How many liters of CO$_2$ are formed at STP by the complete combustion of the propane in a container with a volume of 15.0 L and a pressure of 4.5 atm at 25 degree celcius? The unbalanced equation is

C$_3$H$_8$(g) + O$_2$(g) $\rarr$ CO$_2$(g) + H$_2$O(l)

Approximately 83% of all ammonia produced is used as fertilizer for crops. Ammonia is synthesized from hydrogen and nitrogen gas according to the equation

3 H$_2$(g) + N$_2$(g) $\rarr$ 2 NH$_3$(g)

What volume of hydrogen and nitrogen gas is needed to synthesize 500.0 L of ammonia at STP?

Carbonate-bearing rocks like limestone (CaCO$_3$) react with dilute acids such as HCl to produce carbon dioxide, according to the equation

CaCO$_3$(s) + 2 HCl(aq) $\rarr$ CaCl$_2$(aq) + CO$_2$(g) + H$_2$O(l)

How many grams of CO$_2$ are formed by complete reaction of 33.7 g of limestone? What is the volume in liters of this CO$_2$ at STP?

Many laboratory gases are sold in steel cylinders with a volume of 43.8 L. What mass in grams of argon is inside a cylinder whose pressure is $17,180 \mathrm{k} . \mathrm{Pa}$ at $20^{\circ} \mathrm{C}$ ?

Methane gas, CH$_4$, is sold in a 43.8 L cylinder containing 5.54 kg. What is the pressure inside the cylinder in kilopascals at 20 degree celcius?

Methane gas, $\mathrm{CH}_4$, is sold in a 43.8 L cylinder containing $5.54 \mathrm{~kg}$. What is the pressure inside the cylinder in kilopascals at $20^{\circ} \mathrm{C}$ ?

A weather balloon has a volume of 45.0 L when released under conditions of 745 mm Hg and 25.0 degree celcius. What is the volume of the balloon at an altitude of 10,000 m where the pressure is 178 mm Hg and the temperature is 225 K?

What final temperature (degree celcius) is required for the pressure inside an automobile tire to increase from 2.15 atm at 0 degree celcius to 2.37 atm, assuming the volume remains constant?

If 2.00 g of N$_2$ gas has a volume of 0.40 L and a pressure of 6.0 atm, what is its Kelvin temperature?