73.When a catalyst is added to a reaction system, (A)the equilibrium position is changed (B)the enthalpyis changed (C)the rate is changed (D)all of the above (E)none of the above

78.Condider the following reaction: 3H2(g) + N2(g) « 2NH3(g). All of the following will lead to the production of more NH3(g) EXCEPT (A)removal of NH3(g) (B)a decrease in the volume of the container (C)an increase in pressure by adding N2(g) (D)an increase in pressure by adding argon (E)addition of H2(g)