A Polydisperse mixture of a polymer can be describe by the following composition-molar mass data: `{:(Mass%),25.0,50.0,25.0),(Mi(kgmol^(-1)),1.00,1.20,1.40):}` Calculate the number -average and the mass-average molar masses.

A Polydisperse mixture of a polymer can be describe by the following c

1.	A Polydisperse mixture of a polymer can be describe by the following composition-molar mass data: `{:(Mass%),25.0,50.0,25.0),(Mi(kgmol^(-1)),1.00,1.20,1.40):}` Calculate the number -average and the mass-average molar masses.
Answer» Each of the mass%values must be converted to values of`Ni`.Assuming`100.0g.m`of the mixture ,the amounts of each polymer are: Moles=(Wt.)/(Mw),` `N_(1)=(25)/(1000)=2.50xx10^(-2)mol` `N_(2)=(50)/(1200)=4.17xx10^(-2)mol` `N_(3)=(25)/(1400)=1.79xx10^(-2)mol` `Substituting the values in (i)and(ii)of Illustration 16.4,we get `Mbar(n)={:[((2.50xx10^(-2))(1.00kgmol^(-1))),(+(4.70xx10^(-2))(1.20kgmol^(-1))),(+(1.79xx10^(-2))(1.40kgmol^(-1)))]:}/(2.50xx10^(-2)mol+4.17xx10^(-2)mol+1.79xx10^(-2))=1.18kgmol^(-1)` `Mbar(w)={:[((2.50xx10^(-2)mol)(1.00)^(2)),(+(4.17xx10^(-2))(1.20)^(2)),(+(1.79xx10^(-2))(1.40)^(2)kg^(2)mol^(-1))]:}/([{:((2.50xx10^(-2)mol)(1.00)),(+(4.17xx10^(-2))(1.20)),(+(1.79xx10^(-2))(1.40)):}]Kg)=1.20kgmol^(-1)`