At what pressure and 127oC, the density of O2 gas becomes 1.6 g/L? [a=4.0 atm L2 mol−2, 0.4L mol−1, R=0.08L-atm /K-mol]
Density P=1.5g/L (P=M/V)⇒V=(M/P)
Temp.T=1270c=400k
a=4atmL2mol−2 b=0.4L/mol
By vander waal's gas equation,
[P+n2V2a](V−nb)=nRT (assume 1 mole ⇒n=1)
⇒[P+1(32/1.6)2(4)](321.6−(1)(0.4)) Mass of O2=32
=1×0.08×400
⇒[P+0.01](19.6)=32
⇒P+0.01=1.6326⇒P=1.6227atm