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

Question

Wyatt Atkins · Accepted Answer

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

Thus, in order to determine the number of moles, we take the quotient. #"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"#. What is the number of hydrogen and oxygen atoms?

Owen Ambrose · Answer

undefined To find the number of atoms in 131.97 liters of water vapor at STP, you first need to convert the volume to moles using the molar volume of an ideal gas at STP, which is 22.4 liters/mol. Then, use Avogadro's number (6.022 × 10^23 atoms/mol) to find the number of atoms.

131.97 liters ÷ 22.4 liters/mol = 5.89 moles of water vapor

5.89 moles × 6.022 × 10^23 atoms/mol ≈ 3.54 × 10^24 atoms