Question

【题目】在298K、100kPa时，己知：

2H2O(g)＝O2(g)＋2H2(g)△H1

Cl2(g)＋H2(g)＝2HCl(g)△H2

2Cl2(g)＋2H2O(g)＝4HCl(g)＋O2(g)△H3

则下列关系式正确的是

A.△H3＝△H1－△H2B.△H3＝△H1－2△H2

C.△H3＝△H1＋△H2D.△H3＝△H1＋2△H2

Answer 1

【答案】D

【解析】

令2H2O(g)＝O2(g)＋2H2(g)△H1①

Cl2(g)＋H2(g)＝2HCl(g)△H2②

2Cl2(g)＋2H2O(g)＝4HCl(g)＋O2(g)△H3③

根据盖斯定律可知，③=①+②×2，故△H3＝△H1＋2△H2，故答案为：D。