N2(g) + O2(g) + heat ⟷ 2NO(g)
Is this reaction endo or exothermic?
3H2(g)+N2(g)⟷2NH3(g)
If heat is a product in the reaction above, then the reaction is:

N2 + 3 H2 <-> 2 NH3
What impact did adding N2 at t1 have on NH3?
N2 + 3 H2 <-> 2 NH3
If heat was added at t3, which statement is true: