(1)N 4(g)=2N 2(g) △H=-882kJ.mol -1(2)2NH 3+6OH --6e -=N 2+6H 2O
(3)2N 2O 4+O 2+2H 2O=4HNO 3(4) NaNO 3;CO 2(5)0.5;50%