Question

Three 1.0 liter flasks are filled with H2,O2, and Ne,respectively,at STP(P=1 atm,T=273.15k, V=22.4L/mol)

Answer 1

The question is not complete although i am answering the question according to my sense.

$P=1atm$

$T=273.15K$

$V=1l$

$R=8.314$ $Jmol^{-1}K^{-1}$

Now $PV=nRT$

$n=\dfrac{PV}{RT}=\dfrac{1\times1}{8.314\times273.15}=0.0004moles$