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【答案】應(yīng)助回帖
★ ★ ★ ★ ★ ★ ★ 感謝參與,應(yīng)助指數(shù) +1 fds329: 金幣+2, 感謝應(yīng)助。辛苦了O(∩_∩)O 2012-04-15 02:25:42 lyp627: 金幣+5, 感覺有點(diǎn)沒得到滿意答復(fù) 2012-04-16 15:41:30
化學(xué)反應(yīng)的活化能對(duì)反應(yīng)速率的影響是很顯著的。在相同的溫度下,一個(gè)反應(yīng)的活化能愈大,它的反應(yīng)速率就愈小。多數(shù)化學(xué)反應(yīng)的活化能在15一60千卡·克分子一‘之間,很少有超過80千卡·克分子一‘的,否則它在常溫下的反應(yīng)速率常會(huì)小得不易察覺。可是,有些反應(yīng)的活化能可大到100千卡·克分子一‘以上,但在常溫下,它的反應(yīng)速率還是很大。有些反應(yīng),它們的活化能差別很大,但在相同條件下,它們的反應(yīng)速率卻很相近。此外,還有其他一些問題,這些在經(jīng)典的反應(yīng)速率碰撞理論是很不容易得到滿意的解釋的
對(duì)于理想氣體的反應(yīng),兩種類型的活化焓相等,活化熵不等,但兩種活化熵之間存在定量關(guān)系式:△_r~≠S_m~φ(P~φ)=△_r~≠S_m~φ(c~φ)+(n-1)R1n(P~φ)/RTc~φ。
By two distinct standard states,different expressions calculating rate coefficient of reaction can be deduced from Eyring equation in transition state theory with thermodynamic method.In such conditions,the meanings and numbers of Gibbs free energy,entropy and enthalpy of activation are disparate.However for two kinds of enthalpy of activation,numeriacal value is equal.And it can be linked with the relation of △_r~≠S_m~φ(P~φ)=△_r~≠S_m~φ(c~φ)+(n-1)R1n(P~φ)/RTc~φ. |
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