Neco 2020 Chemistry Question 48

Practice objective / multiple choice question 48 from the 2020 Neco Chemistry examination.

Neco 2020 Chemistry Objective / Multiple Choice Hard Difficulty
Question 48 NECO • 2020 • CHEMISTRY • objective

A polymer undergoes first‑order thermal degradation. At 300 K the rate constant is \(k_1 = 2.0\times10^{-5}\ \text{s}^{-1}\). The activation energy for the process is \(E_a = 85\ \text{kJ mol}^{-1}\). (i) Calculate the rate constant \(k_2\) at 350 K using the Arrhenius equation. (ii) Determine the half‑life \(t_{1/2}\) of the polymer at 350 K. Express \(k_2\) in scientific notation to two significant figures and \(t_{1/2}\) in seconds to three significant figures.

Answer Options

A. k = 1.3×10^{-3} s^{-1}, t½ = 5.30×10^{2} s
B. k = 3.0×10^{-3} s^{-1}, t½ = 2.0×10^{2} s
C. k = 2.6×10^{-2} s^{-1}, t½ = 2.65×10^{1} s
Correct Answer D. k = 2.6×10^{-3} s^{-1}, t½ = 2.65×10^{2} s
Correct Answer
D
Correct Option:
k = 2.6×10^{-3} s^{-1}, t½ = 2.65×10^{2} s

About This Question

This is Neco 2020 Chemistry Question 48. It is one of the objective questions from the 2020 Neco Chemistry examination.

Difficulty level: Hard .

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