If the oxygen being fed into the system
4NH3(g) + 5O2(g) <--> 4NO(g) + 6H20(g) + 950kJmol-1
is heated, how will the equilibrium shift?
The reaction is exothermic, that is gives off heat, or raising the temperature. If heat is added, then the reaction will shift to undo what the change was, so it will shift left.