A reaction has a rate constant of 4 x 10 -3 s -1 at 300 K and 1.6 x 10 -2 s -1 at 340 K. Using the Arrhenius equation, the activation energy is closest to which value (R = 8.314 J/K/mol)?

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A reaction has a rate constant of 4 x 10-3 s-1 at 300 K and 1.6 x 10-2 s-1 at 340 K. Using the Arrhenius equation, the activation energy is closest to which value (R = 8.314 J/K/mol)?

Answer: 29.4 kJ/mol.

A 58.8 kJ/mol
B 29.4 kJ/mol
C 117.6 kJ/mol
D 14.7 kJ/mol

Correct answer: B. 29.4 kJ/mol

Explanation: Using log(k2/k1) = Ea/(2.303R) x (1/T1 - 1/T2), with k2/k1 = 4, T1 = 300 K, T2 = 340 K, solving gives Ea approximately 29.4 kJ/mol.

First-order decay curve: concentration halves every t½, and that half-life is constant - a defining test for first-order kinetics.

Concept context

Study the speed of reactions and what affects it: concentration, temperature, and catalysts. Covers rate law, order of reaction, the Arrhenius equation, and reaction mechanisms step by step.

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A reaction has a rate constant of 4 x 10<sup>-3</sup> s<sup>-1</sup> at 300 K and 1.6 x 10<sup>-2</sup> s<sup>-1</sup> at 340 K. Using the Arrhenius equation, the activation energy is closest to which value (R = 8.314 J/K/mol)?

Concept context

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