A:
B:
4NH3(g)+6NO(g)⇌5N2(g)+6H2O(g)△H1
己知:①H2O(l)=H2O(g)△H2
②4NH3(g)+5O2(g)=4NO(g)+6H2O(g)△H3
则NH3(g)的标准燃烧热的热化学方程式____.
如图,AB是⊙O的直径,∠CAB=∠DAB.求证:AC=AD.