Neco Model Questions Vol1 2019 Chemistry Question 45

Practice objective / multiple choice question 45 from the 2019 Neco Model Questions Vol1 Chemistry examination.

Neco Model Questions Vol1 2019 Chemistry Objective / Multiple Choice Hard Difficulty
Question 45 NECO_MODEL_QUESTIONS_VOL1 • 2019 • CHEMISTRY • objective

A step‑growth polymerisation of adipic acid with hexanol yields poly(hexyl adipate). The repeat unit has a molar mass of 230.3 g mol\(^{-1}\). In a batch, 0.500 mol of each monomer are allowed to react and the extent of reaction reaches 80 %. (a) Determine the number‑average degree of polymerisation \(DP_n\). (b) Calculate the number‑average molecular weight \(M_n\). (c) Using the Mark-Houwink relation \([\eta]=K\,M_n^{\,a}\) with \(K=1.2\times10^{-4}\,\text{dL g}^{-1}\) and \(a=0.75\), estimate the intrinsic viscosity of the polymer solution.

Answer Options

Correct Answer A. DP_n = 5; M_n = 1.15×10³ g mol⁻¹; [η] ≈ 2.4×10⁻² dL g⁻¹
B. DP_n = 5; M_n = 1.15×10³ g mol⁻¹; [η] ≈ 3.5×10⁻² dL g⁻¹
C. DP_n = 6; M_n = 1.38×10³ g mol⁻¹; [η] ≈ 3.0×10⁻² dL g⁻¹
D. DP_n = 4; M_n = 9.2×10² g mol⁻¹; [η] ≈ 1.8×10⁻² dL g⁻¹
Correct Answer
A
Correct Option:
DP_n = 5; M_n = 1.15×10³ g mol⁻¹; [η] ≈ 2.4×10⁻² dL g⁻¹

About This Question

This is Neco Model Questions Vol1 2019 Chemistry Question 45. It is one of the objective questions from the 2019 Neco Model Questions Vol1 Chemistry examination.

Difficulty level: Hard .

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