Question

一定条件下合成氨反应达到平衡,测得混合气体中氨气的体积分数为20%,与反应前的体积相比,反应后体积缩小的百分率是多少?

Answer 1

设反应后体积为1,则生成NH3 0.2,还剩N2和H20.8,(because 0.2 + 0.8 =1.0)

反应消耗了N2和H2体积0.4,(in the reaction

N2+3H2=2NH3

production of two volumes of NH3 needs 1 volume of N2 和 3 volumes of H20,so for 0.2 NH3,消耗了N2和H2体积= 0.1 + 0.3 =0.4

所以原来总体积为1.2,

消耗了N2和H2体积 + 还剩N2和H20体积 = 0.4 + 0.8 =1.2

缩小了0.2,百分比为：

0.2/1.2=16.7%