If the graphic representation of the energy levels of the reactants and products in a chemical reaction looks like this:
Which of the following statements are true?
I. The activation energy for the forward reaction is represented by the “a” portion.
II. The activation energy for the forward reaction is
雅思托福在线一对一外教课程免费领取：www.acadsoc.com.cn
represented by the “b” portion of the graph.III. The “a” portion is the energy given off in the forward reaction.
(A) I only
(B) II only
(C) I and III only
(D) II and III only
(E) I, II, and III
生词:
reactant 反应物
product 产物
解析:
本图中，a是要能进行正向反应的活化能。a+b是要能进行反向反应的活化能。b是正向反应释放的能量。
因此只有I. The activation energy for the forward reaction is represented by the “a” portion 正确。答案选择(A)。