Question

If a polythene sample contains two monodisperse fractions in the ratio 2:3 with degree of polymerisation 100 and 200 respectively, then its weight average molecular weight will be:

a. 4900

b. 4600

c. 4300

d. 5200

Explain briefly

Ans. a

Please explain briefly.

Answer 1

the answer for this is A

Answer 2

Hey dear,

● Answer -
4480

● Explanation -
Molar mass of polymer is calculated by-
Molar mass of polymer = Degree of polymerization × mass of monomer

For 1st polymer,
M1 = 100 × 28
M1 = 2800

For 2nd polymer,
M2 = 200 × 28
M2 = 5600

Average molar mass of polymer -
M = (2×2800 + 3×5600) / (2+3)
M = 4480

Therefore, average molar mass of polymer is 4480.

Hope this helps you...