The molar mass of mixture of CO and CO2 can be obtained in two ways .The comparison of two moles gives values of each
(I) Let n1 mole of CO and (100−n1) mole of CO2 are presented in 100 mole
avg molar mass=n1∗28+(100−n1)∗44100
(II) Also for mixture P=(730/760)atm T=303K ,d=1.50glitre−1
PV=WmRT
P=WVmRT
730760 =1.50M*0.821*303
M=38.85gmol−1
A comparison of equation (1) and (ii) yields n1=32.19
mole % of CO=32.190
and Mole % of CO2=67.81
so nearest integer is 68.