An oxygen gas container has a volume of 20.0 L. How many grams of oxygen are in the container if the gas has a pressure of 876 mmHg at 23 C?

1 Answer
Jan 8, 2018

Answer:

There are #30.4# grams of oxygen in the sample.

Explanation:

Use the ideal gas law. We are given the pressure, the temperature and the volume. The gas constant will be #62.36#

#PV = nRT#

We're looking for #n#, the number of moles in the sample. Note that #23˚C= 23 + 273 = 296K#

#(20.0 L)(876 mmHg) = n(62.36 mmHg L k^-1 mol^-1)296K#

If we cancel all units we're left with

#n = 0.949 # mol

Knowing that

#"molar mass" = ("number of grams per sample")/("number of moles")#

And that the molar mass of oxygen is #32.00 g/(mol)#, we can solve for number of grams in sample.

#32.00 g/(mol) * 0.949 mol = g#

#g = 30.4 " grams"#

Notice I rounded to #3# sig figs.

Hopefully this helps!