Question

A polymer has the following composition: 100 molecules of molecular mass 1000 g/mol, 200 molecules of molecular mass 2000 g/mol and 500 molecules of molecular mass 5000 g/mol. the no. of avarage molecular weight is
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Answer 1

Explanation:

100 molecules of molecular mass 1000 g/mol, 200 molecules of molecular mass 2000 g/mol and 500 molecules of - 20834389.

Answer 2

Answer:

PDI=1.19

Explanation:

no of polymers                   molecular wt^ of polymers

100                                       1000

200                                      2000

500                                      5000

Mn=ΣNiMi/ΣNi

    =(100x1000)+(200x2000)+(500x5000) / 100+200+500

    =3750

    =3.7 x 10^-3

Mw=ΣNiMi^2 (only Mi has the square(^2)) / ΣNiMi

     =(100x1000^2)+(200x2000^2)+(500x5000^2) / (100x1000)+(200x2000)+(500x5000)
     = 4466.7

     = 4.4667 x 10^3

PDI = Mw / Mn
      =4466.7 / 3750
      = 1.19