Chemistry help??

Question

I have been going over some homework and have a question:
An empty classroom contains 240kl of air at SATP( 25C, 100kPa).
(a) Calculate the amount of moles of nitrogen, oxygen, argon, and carbon dioxide in the room.
(b)Calculate the mass of each gas.
(c)How will mass of each gas change after class is in it for 1h.
(d)At SATP, respirationg in a classroom converts about about 400L of oxygen per student par school day to carbon dioxide. 30 studetns per period of time and air is stagnant, what % of oxygen is consumed?

You help would be much apreciated,
Stuck person

Answer 1

Base on the conditions supplied determine the percentages of each gas in the atmosphere (using ref 1, for example) "It contains roughly 78% nitrogen, 21% oxygen, 0.97% argon, 0.04% carbon dioxide, and trace amounts of other gases, in addition to water vapor."

Also we know that at these conditions At sea level (100kPa) and at 25 °C dry air has a density of approximately 1.184 kg/m^3

Computing for nitrogen N2 1 mole = 2(14.0067)=28.0124gm/mole
N2 kg/m^3=1.184(.78)=0.92352kg/m^3
Number of moles =0.92352kg/m^3/28.0124gm/mole=32.968 moles per cubic meter.
We have 1000 liters in 1 m^3 and the room is 240kl or 240 m^3.
then total moles of N2=
=240x32.968 =
7912.4 moles of N2

Similarly solve for the rest.
However,
Be careful with Argon it's molecule is mono atomic, so we have Ar1=1x 39.948=39.948g/mole.