What is the volume of #2# #mol# of oxygen, #O_2#, at STP?

2 Answers
anor277
Feb 29, 2016

You need to specify (i) a pressure, and (ii) a temperature, before the molar quantity can be calculated.

Explanation:

If we assume standard laboratory conditions, #25# #""^@C# and #1# #atm# (or thereabouts; the standard is slightly different now!), #2L# dioxygen gas represents, #(2L)/(25.4*L*mol^-1)# #""approx 1/12*mol #.

David G.
Feb 29, 2016

Assuming that the gas is at standard temperature and pressure (STP), one mole of any gas occupies #22.4# #L#. This means the number of moles of #O_2# is #2/22.4=0.089# #mol#.

Explanation:

The Ideal Gas Law makes certain assumptions about the gases: that the particles are very tiny and featureless and that there is no force acting between them. If these assumptions are correct, then one mole of any gas will occupy #22.4# #L# at STP.

The assumptions are not quite the case for #O_2#, but the deviations from it are small enough that we can still use this approach and receive an accurate answer.

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