Question

【題目】氯原子對O3的分解有催化作用：

O3(g)＋Cl(g)===ClO(g)＋O2(g) ΔH1 ①

ClO(g)＋O(g)===Cl(g)＋O2(g) ΔH2 ②

該反應(yīng)的能量變化如圖所示，下列敘述中正確的是( )

A．反應(yīng)O3(g)＋O(g)===2O2(g)的ΔH＝E1－E2

B．反應(yīng)O3(g)＋O(g)===2O2(g)的ΔH＝E2－E3

C．反應(yīng)O3(g)＋O(g)===2O2(g)是吸熱反應(yīng)

D．反應(yīng)O3(g)＋O(g)===2O2(g)的ΔH＝ΔH1＋ΔH2

Answer 1

【答案】D

【解析】將①式O3(g)＋Cl(g)===ClO(g)＋O2(g) ΔH1與②式ClO(g)＋O(g)===Cl(g)＋O2(g) ΔH2相加，整理可得：反應(yīng)O3(g)＋O(g)===2O2(g)的 ΔH＝ΔH1＋ΔH2。由于反應(yīng)物的總能量高于生成物的總能量，所以反應(yīng)O3(g)＋O(g)===2O2(g)為放熱反應(yīng)。因此正確選項為D。