Gce Model Questions Vol1 2022 Chemistry Question 42

Practice objective / multiple choice question 42 from the 2022 Gce Model Questions Vol1 Chemistry examination.

Gce Model Questions Vol1 2022 Chemistry Objective / Multiple Choice Hard Difficulty
Question 42 GCE_MODEL_QUESTIONS_VOL1 • 2022 • CHEMISTRY • objective

In a step‑growth polymerisation a diacid (M_r = 146) reacts with a diamine (M_r = 60). The initial molar ratio of acid to amine is 1.02 : 1 and the extent of reaction is p = 0.95. (a) Calculate the number‑average degree of polymerisation X_n using Carothers equation for unequal stoichiometry. (b) Using the repeat‑unit mass (M_r = 170 g mol⁻¹), determine the number‑average molecular weight M_n. Give X_n to the nearest whole number and M_n to three significant figures.

Answer Options

A. X_n = 13, M_n = 2.20×10³ g mol⁻¹
B. X_n = 15, M_n = 2.55×10³ g mol⁻¹
C. X_n = 19, M_n = 3.23×10³ g mol⁻¹
Correct Answer D. X_n = 17, M_n = 2.86×10³ g mol⁻¹
Correct Answer
D
Correct Option:
X_n = 17, M_n = 2.86×10³ g mol⁻¹

About This Question

This is Gce Model Questions Vol1 2022 Chemistry Question 42. It is one of the objective questions from the 2022 Gce Model Questions Vol1 Chemistry examination.

Difficulty level: Hard .

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