已知C2H4(g)和C2H5OH(1)的燃烧热分别是-1411.0kJ·mol-1和-1366.8kJ mol-1，则由C2H4(g)和H2O(l)反应生成C2H5OH(l)的△H为A.-44.2 kJ·mol-1B.+44.2 kJ·mol-1编号起始状态(mol)平衡时HBr(g)物质的量(mol)C.-330 kJ·mol-1D.+330 kJ·mol-1
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A解析由题意，得：
C2H4(g)+3O2(g)=2CO2(g)+2H20(l) △H1 =-1411.0kJ·mol-1 ①
C2H5OH(1)+3O2(g)=2CO2(g)+3H20(l) △H2 =-1366.8kJ mol-1 ②
C2H4(g)+H2O(l)=C2H5OH(l) ③
①-②=③，所以：△H3 =△H1-△H2，故A正确；