An oxygen cylinder having volumn `30` litre shows a initial gauge pressure `15` atm and temperature `27^(@)C`. Some oxygen is taken out from the cylinder, so that the gauge pressure comes down to `11` atm and temperature comes down to `17^(@)C`. What amount of gas was taken out from the cylinder ?

Answer

`0.139` kg

Explanation

No. of moles withdrawn = `n_(1) -n_(2) = (Deltam)/(M)`
`implies Deltam = M(n_(1) - n_(2)) = M((P_(1)V_(1))/(RT_(1)) - (P_(2)V_(2))/(RT_(2)))`
= `32[(15 xx 10^(5) xx 30 xx 10^(-3))/(300 xx 8.314) - (11 xx 10^(5) xx 30 xx 10^(-3))/(290xx 8.314)]`
=`0.139` kg