有關反應平衡常數的問題

[匿名]

2013-05-28 8:08 pm

ammonia is prepareed industrially by the reaction
N2+3H2 = 2NH3

for the reaction. H=-92.2KJ and K (at 298K) =4.0*10^8.
when the temperautre of the reaction is increased to 773K,which of the following is true

a) k for the reaction will be larger at 773K than at 298K
b) at equilibrium, more NH3 is present at 773K than at 298K
c) product formation (at equilibrium) is not favored as the temperature is raised
d) the reaction of N2 with H2 to from ammonia is endothermic
e) none of the above is true

答案是C
但是我不明白
溫度升高反應不是吸熱方向(即往左)嗎
且溫度升高K值亦會有變化,為甚麼答案是C呢

我的概念還沒很清晰
尋求高人指點

回答 (1)

andrew

2013-05-29 9:19 am

✔ 最佳答案

C) product formation (at equilibrium) is not favored as the temperatureis raised
意思是：「當溫度上升時，（平衡時）不利於產品的生成。」

產品（product）是指 NH3，位於反應式（equation）的右方。
正向反應是放熱的（forward reaction is exothermic），而逆向反應是吸熱的（backward reaction isendothermic）。當溫度上升時，有利於吸熱反應，故平衡位置（equilibrium position）向左移，故不利位於反應式右方的 NH3 的生成。因此，(C) 正確。

2013-05-29 01:20:16 補充：
「產品」應是「產物」之誤。

參考: andrew, andrew

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