Imagine the room it has Height =20 m Temperature =273 k Pressure=5 atm Volume fraction of oxygen in air is 21%. Calculate the mass of oxygen in room.

Answer 1

The room is probably a cube, so the volume of the room is (20m)³=800m³

Convert that to Liters.

800m³ (100cm/1m)³=8 * 10⁸ cm³

1mL=1cm³, so volume is

=8 * 10⁸ mL

convert to L

8 * 10⁸ mL(1L/1000mL)=8 * 10⁵ L

21% of the air is oxygen, apply that:

0.21(8E5)=1.68E5 L O2

use the ideal gas law, solve for n, moles, then convert that to grams with the molar mass

PV=nRT

5(1.68E5)=n(0.08206)273

n=3.75E4 mol

convert that to grams with the molar mass

1mol O2=32g

3.75E4mol(32g/mol)=1.2E6 g O2