For the data given below, (12 marks) a. Calculate the number-average molecular weight of polypropylene (CH₂CHCH3) (8 marks) b. What is the average number of repeat units in the polymer chains? Atomic weights of hydrogen and carbon are 1.008 and 12.011 g/mol, respectively. (4 marks) Molecular weight range (g/mol) Number fraction. 8,000-16,000 16,000-24,000 24,000-32,000 32,000-40,000 40,000-48,000 48,000-56.000 0.05 0.16 0.24 0.28 0.20 0.07​