according to le chateliers principle, what is the effect on the products when N2 is added to the equilibrium mixture of each of the following reactions? a)2NH3(g)<>3H2(g)+N2(g). b)N2(g)+O2(g)<>2NO(g). c)2NO2(g)<>N2(g)+2O2(g). d)4NH3(g)+3O2(g)<>2N2(g)+6H2O(g)