B. Calculate number of moles of hydrogen in 0.448 litre of hydrogen gas at STP

Given : volume of hydrogen at STP =0.448 L

To find : number of moles of hydrogen

Formula : number of moles of a gas =\({Volume\space of \space a \space gas\space at \space STP \over Molar \space volume \space of \space gas}\) 

Solution :

 number of moles of a gas =\({Volume\space of \space a \space gas\space at \space STP \over Molar \space volume \space of \space gas}\) 

=\(0.448 \over 22.4 \)          ---{ volume of gas at stp = 22.4 dm³ mol^-1} 

=0.02 mol 

\(\therefore \) number of moles of hydrogen in  0.448 L at STP is = 0.02 mol