题目

已知：2H2 ( g ) + O2 ( g ) = 2H2O ( l )      △H = －Q1 kJ/mol 2H2 ( g ) + O2 ( g ) = 2H2O ( g )             △H = －Q2 kJ/mol          CH4 ( g ) + 2O2 ( g ) = 2H2O ( l ) + CO2 ( g )   △H = －Q3 kJ/mol 常温下，取体积比为4 ：1的甲烷和氢气的混合气体11.2 L（标准状况下）经完全燃烧后恢复到常温，则放出的热量为             。 — Are you sure you have to ? It’s been very late.— I don’t know __________ I can do it if not now.A. where B. why C. how D. When