How many atoms are in 131.97 liters of water vapor at STP?

1 Answer
Jun 3, 2017

Answer:

Well the molar volume at #"STP"#, is #22.4*L*mol^-1#. (Check this value out with your syllabus...........)

Explanation:

And so we take the quotient to get the number of moles.............

#"Number of moles"=(131.97*L)/(22.4*L*mol^-1)=5.8921*mol#,

Note that this is dimensionally consistent as the #L# cancels out, and #1/(mol^-1)=1/(1/(mol))=mol# as required.

Now we know that in ONE MOLE, there are #"Avogadro's Number"# of particles, i.e. #6.0221xx10^23*mol^-1#

And thus.......................#"number of particles" = 6.0221xx10^23*mol^-1xx5.8921*mol=#

#3.5479xx10^24# #"individual gas particles........"#

And since an individual gas particles CONTAINS THREE ATOMS, i.e. #H_2O(g)#, there are................

#3.5479xx10^24*"molecules"xx3*"atoms"*"molecule"^-1#

#=1.0644xx10^25*"atoms"#.

How many oxygen atoms, and how many hydrogen atoms?