How many atoms of Hydrogen are in 67.2 L of H2 at STP?

67.2 L / 22.414 L/mol = moles of H2 gas

Then:

Moles of H2 gas times 6.022 x 10^23 mol^-1 = molecules of H2

Finally, since there are two atoms of H per molecule:

molecules of H2 times 2 = the answer you seek.

• Sir waqar