Neco Model Questions Vol1 2022 Chemistry Question 38

Practice objective / multiple choice question 38 from the 2022 Neco Model Questions Vol1 Chemistry examination.

Neco Model Questions Vol1 2022 Chemistry Objective / Multiple Choice Hard Difficulty
Question 38 NECO_MODEL_QUESTIONS_VOL1 • 2022 • CHEMISTRY • objective

A polymer sample consists of four types of chains with the following degree of polymerisation (DP) and number fractions: DP = 1000 (10 %), DP = 500 (30 %), DP = 200 (40 %), DP = 50 (20 %). The monomer molar mass is \(100\ \text{g mol}^{-1}\). Calculate the number‑average molecular weight \(M_n\), the weight‑average molecular weight \(M_w\), and the polydispersity index \(\text{PDI}=M_w/M_n\) for the sample.

Answer Options

A. M_n = 3.4×10^4 g mol⁻¹; M_w ≈ 5.20×10^4 g mol⁻¹; PDI ≈ 1.53
Correct Answer B. M_n = 3.4×10^4 g mol⁻¹; M_w ≈ 5.63×10^4 g mol⁻¹; PDI ≈ 1.66
C. M_n = 3.6×10^4 g mol⁻¹; M_w ≈ 6.00×10^4 g mol⁻¹; PDI ≈ 1.67
D. M_n = 3.2×10^4 g mol⁻¹; M_w ≈ 5.10×10^4 g mol⁻¹; PDI ≈ 1.59
Correct Answer
B
Correct Option:
M_n = 3.4×10^4 g mol⁻¹; M_w ≈ 5.63×10^4 g mol⁻¹; PDI ≈ 1.66

About This Question

This is Neco Model Questions Vol1 2022 Chemistry Question 38. It is one of the objective questions from the 2022 Neco Model Questions Vol1 Chemistry examination.

Difficulty level: Hard .

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