① 2NH3 ( g ) +3N2O ( g ) →4N2( g ) + 3H2O ( l ) △rHm1=﹣1010kj/mol
② N2O ( g ) +3H2 ( g ) →N2H4 ( l ) + H20 ( l ) △rHm2=﹣317kj/mol
③ 2NH3 ( g ) + 1/2O2 ( g ) → N2H4 ( l ) +H2O ( l ) △rHm3=-143kj/mol
④ H2 ( g ) + 1/2O2 ( g ) → H2O ( l ) △rHm4=﹣143kj/mol