Waec Model Questions Vol1 2018 Chemistry Question 20

Practice objective / multiple choice question 20 from the 2018 Waec Model Questions Vol1 Chemistry examination.

Waec Model Questions Vol1 2018 Chemistry Objective / Multiple Choice Hard Difficulty
Question 20 WAEC_MODEL_QUESTIONS_VOL1 • 2018 • CHEMISTRY • objective

In a batch polymerisation, 1500 g of ethylene glycol (M = 62 g mol⁻¹) reacts with 2000 g of terephthalic acid (M = 166 g mol⁻¹) to form poly(ethylene terephthalate) (PET). The repeat unit of PET has a molar mass of 192 g mol⁻¹ (loss of one water molecule per ester link).\n(a) Determine the degree of polymerisation (DP).\n(b) Calculate the number‑average molecular weight (Mₙ).\n(c) Using the Mark-Houwink equation η = K·Mₙ^{a} with K = 1.2×10⁻⁴ Pa·s·(g mol⁻¹)^{‑a} and a = 0.7, compute the viscosity η of the polymer melt.

Answer Options

A. 0.020 Pa·s
B. 0.054 Pa·s
Correct Answer C. 0.027 Pa·s
D. 0.013 Pa·s
Correct Answer
C
Correct Option:
0.027 Pa·s

About This Question

This is Waec Model Questions Vol1 2018 Chemistry Question 20. It is one of the objective questions from the 2018 Waec Model Questions Vol1 Chemistry examination.

Difficulty level: Hard .

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