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问:升高温度会减小活化能吗? 答:升高温度,反应物分子平均能量增加,活化分子最低能量不变,所以活化分子最低能量与分子平均能量之差,即活化能会随温度升高而减小。但是,温度改变时,活化能改变的幅度很小,这是因为活化分子最低能量比分子平均能量大得多。例如:N_2O_5分解时活化分子最低能量是24.7千卡/摩,而50℃时分子平均能量仅有0.963千卡,摩。可见活化能大小,主要取决于活化分子最低能量。N_2O_5分解反应,温度由50℃升到100℃,由于分子平均能量的增加,使活化能仅减小0.168千卡/摩。所以可以忽略温度变化对活化能的影响。升高温度,活化能变化很小,反应速度为什么会加快呢? 改变温度时,分子的能量普遍增加,分子能量重新分配,使分子能量分布曲线向右移动,代表活化分
Q: Does raising the temperature decrease the activation energy? A: When the temperature is raised, the average energy of the reactant molecules increases, and the lowest energy of the activated molecules remains unchanged, so the difference between the lowest energy of the activated molecules and the average energy of the molecules, that is, the activation energy will vary with temperature. Increase and decrease. However, when the temperature changes, the magnitude of the change in activation energy is small, because the lowest energy of the activation molecule is much greater than the average energy of the molecule. For example, the lowest energy of activated molecules at the decomposition of N_2O_5 is 24.7 kcal/mole, while the average energy at 50°C is only 0.963 kcal. It can be seen that the size of the activation energy mainly depends on the lowest energy of the activation molecule. N 2 O 5 decomposition reaction, the temperature rose from 50 ° C to 100 ° C, due to the increase in the average molecular energy, the activation energy is reduced by only 0.168 kcal / M. Therefore, the effect of temperature change on activation energy can be ignored. When the temperature is raised, the activation energy changes very little. Why does the reaction rate accelerate? When the temperature is changed, the energy of the molecule generally increases, the molecular energy is redistributed, and the molecular energy distribution curve shifts to the right, representing the activation score.