题目内容
【题目】已知反应:H2(g)+ O2(g)=H2O(g)△H1
N2(g)+O2(g)=NO2(g)△H2
N2(g)+ H2(g)=NH3(g)△H3
则反应2NH3(g)+ O2(g)=2NO2(g)+3H2O(g)的△H为( )
A.2△H1+2△H2﹣2△H3
B.△H1+△H2﹣△H3
C.3△H1+2△H2+2△H3
D.3△H1+2△H2﹣2△H3
【答案】D
【解析】H2(g)+ O2(g)=H2O(g)△H1 ①
N2(g)+O2(g)=NO2(g)△H2②
N2(g)+ H2(g)=NH3(g)△H3③
将方程式③×2+②×2﹣2×③得2NH3(g)+ O2(g)=2NO2(g)+3H2O(g)△H=3△H1+2△H2﹣2△H3 , 所以选D.
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