posted by Fiona .
for the reaction
4NH3(g) + 5O2(g) <--> 4NO(g) + 6H2O(g)
if H = -950kJmol-1, does that mean it's an exothermic reaction?
Ooops pressed Post too quickly.
Yes it is exothermic. Delta H is negative so heat is lost from the system. If delta H is positive a reaction is endothermic as it is gaining heat.