The chemisorption of hydrogen on manganese is activated, but only weakly so. Careful measurements have shown that it proceeds 20 times faster at 1000 K than at 600 K. The activation energy for chemiso

Question

The chemisorption of hydrogen on manganese is activated, but only weakly so. Careful measurements have shown that it proceeds 20 times faster at 1000 K than at 600 K. The activation energy for chemisorption (in kcal/mol) is (e³ = 20)

Prashant Kotian · Accepted Answer

Correct answer: 9. Applying the Arrhenius equation: ln(k₂/k₁) = (Eₐ/R) [1/T₁ - 1/T₂]. Given k₂/k₁ = 20 and e³ = 20, we have ln(20) = 3. So, 3 = (Eₐ / R) [1/600 - 1/1000]. Using R = 2 cal/(mol·K): 3 = (Eₐ / 2) × (400 / 600000) = (Eₐ / 2) × (1 / 1500). Eₐ = 3 × 2 × 1500 = 9000 cal/mol = 9 kcal/mol. Therefore, correct answer is 9.

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