化学反应N 2 +3H 2 =2NH 3 的能量变化如下图所示,该反应的热化学方程式是( )
A.
N 2 (g)+3H 2 (g) ='==' 2NH 3 (1)△ H =2(a-b-c)kJ·mol -1
B.
N 2 (g)+3H 2 (g) ='==' 2NH 3 (g)△ H =2(b-a)kJ·mol -1
C.
N 2 (g)+ H 2 (g) ===NH 3 (1)△ H =(b+c-a)kJ·mol -1
D.
N 2 (g)+ H 2 (g) ===NH 3 (g)△ H =(a+b)kJ·mol -1