1) H₂(g)+Br₂(g)➝2HBr(g) has a heat of reaction of ___ kJ.

2)CH₄(g)+I₂(g)➝CH₃I(g)+HI(G) has a heat of reaction of ___kj.

3)N₂H₄(I)+O₂(g)➝N₂(g)+ 2 H₂O(g) has a heat of reaction of __kj.