Question

【题目】已知反应：H2(g)＋O2(g)===H2O(g) ΔH1 ； N2(g)＋O2(g)===2NO(g) ΔH2 ；N2(g)＋3H2(g)===2NH3(g) ΔH3 ，则反应2NH3(g)＋O2(g)===2NO(g)＋3H2O(g)的ΔH为( )

A．3ΔH1＋2ΔH2－ΔH3 B．ΔH1＋ΔH2－ΔH3

C．3ΔH1＋ΔH2＋ΔH3 D．3ΔH1＋ΔH2－ΔH3

Answer 1

【答案】D

【解析】

试题分析：已知反应：①H2(g)＋O2(g)===H2O(g) ΔH1 ；②N2(g)＋O2(g)===2NO(g) ΔH2 ；③N2(g)＋3H2(g)===2NH3(g) ΔH3 ，根据盖斯定律：①×3+②-③得反应2NH3(g)＋O2(g)===2NO(g)＋3H2O(g)的ΔH=3ΔH1＋ΔH2－ΔH3，选D。