A first-order reaction has rate constants of 4.6 x 10^-2 s^-1
and 5.7 x 10^-2 s^-1 at 0°C and 20.°C, respectively. What is the value of the activation energy?
Activation energy = ___ kJ/mol?
2019-03-12 3:02 pm
回答 (1)
2019-03-12 10:15 pm
At T₁ = 0°C = 273 K, k₁ = 4.6 × 10⁻² s⁻¹
At T₂ = 20°C = (273 + 20) K = 293 K, k₂ = 5.7 × 10⁻² s⁻¹
Gas constant, R = 8.314 J mol⁻¹ K⁻¹
Arrhenius equation:
ln(k₁/k₂) = (Eₐ/R) [(1/T₂) - (1/T₂)]
Hence, Eₐ = R ln(k₁/k₂) / [(1/T₂) - (1/T₂)]
Activation energy, Eₐ
= 8.314 × ln[(4.6 × 10⁻²)/(5.7 × 10⁻²)] / [(1/293) - (1/273)]
= 7100 J mol⁻¹ (to 2 sig. fig.)
= 7.1 kJ mol⁻¹
At T₂ = 20°C = (273 + 20) K = 293 K, k₂ = 5.7 × 10⁻² s⁻¹
Gas constant, R = 8.314 J mol⁻¹ K⁻¹
Arrhenius equation:
ln(k₁/k₂) = (Eₐ/R) [(1/T₂) - (1/T₂)]
Hence, Eₐ = R ln(k₁/k₂) / [(1/T₂) - (1/T₂)]
Activation energy, Eₐ
= 8.314 × ln[(4.6 × 10⁻²)/(5.7 × 10⁻²)] / [(1/293) - (1/273)]
= 7100 J mol⁻¹ (to 2 sig. fig.)
= 7.1 kJ mol⁻¹
收錄日期: 2021-05-01 22:26:18
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