At a certain temperature, KC = 1.8 X 104 for the reaction  N2(g)   + 3 H2(g)   = 2NH3(g) . If the equilibrium concentrations of N2 and NH3 are 0.015M and 2.00M respectively, What is the equilibrium concentration of H2?

What is the law of mass action? Is it true that the value of K depends on the amounts of reactants and products mixed together initially? Explain. Is it true that reactions with large equilibrium constant values are very fast? Explain. There is only one value of the equilibrium constant for a particular system at a particular temperature, but there is an infinite number of equilibrium positions. Explain.

The value of the equilibrium constant, K, is dependent on which of the following? (There may be more than one answer.) a. the initial concentrations of the reactants b. the initial concentrations of the products c. the temperature of the system d. the nature of the reactants and products Explain.

The decomposition of PCl5(g) to form PCl3(g) and Cl2(g) has Kc = 33.3 at a high temperature. If the initial concentration of PCl5 is 0.1000 M, what are the equilibrium concentrations of the reactants and products?

. Explain what it means that a reaction has reached a state of chemical equilibrium. Explain why equilibrium is a dynamic state: Does a reaction really “stop” when the system reaches a state of equilibrium? Explain why, once a chemical system has reached equilibrium, the concentrations of all reactants remain constant with time. Why does this constancy of concentration not contradict our picture of equilibrium as being dynamic? What happens to the rates of the forward and reverse reactions as a system proceeds to equilibrium from a starting point where only reactants are present?

Because calcium carbonate is a sink for CO32- in a lake, the student in Exercise 12.39 decides to go a step further and examine the equilibrium between carbonate ion and CaCOj. The reaction is Ca2+(aq) + COj2_(aq) ** CaCO,(s) The equilibrium constant for this reaction is 2.1 X 10*. If the initial calcium ion concentration is 0.02 AI and the carbonate concentration is 0.03 AI, what are the equilibrium concentrations of the ions? A student is simulating the carbonic acid—hydrogen carbonate equilibrium in a lake: H2COj(aq) H+(aq) + HCO}‘(aq) K = 4.4 X 10"7 She starts with 0.1000 AI carbonic acid. What are the concentrations of all species at equilibrium?

12.103 Methanol, CH3OH, can be produced by the reaction of CO with H2, with the liberation of heat. All species in the reaction are gaseous. What effect will each of the following have on the equilibrium concentration of CO? (a) Pressure is increased, (b) volume of the reaction container is decreased, (c) heat is added, (d) the concentration of CO is increased, (e) some methanol is removed from the container, and (f) H2 is added.

Consider the system 4NH3(g)+3O2(g)2N2(g)+6H2O(l)H=1530.4kJ (a) How will the concentration of ammonia at equilibrium be affected by (1) removing O2(g)? (2) adding N2(g)? (3) adding water? (4) expanding the container? (5) increasing the temperature? (b) Which of the above factors will increase the value of K? Which will decrease it?

Calculate the value of the equilibrium constant for the reaction N2(g)+2O2(g)2NO2(g) if the concentrations of the species at equilibrium are [N2] = 0.0013, [O2] = 0.0024, and [NO2] = 0.00065.

During an experiment with the Haber process, a researcher put 1 mol N2 and 1 mol H2 into a reaction vessel to observe the equilibrium formation of ammonia, NH3. N2(g)+3H2(g)2NH3(g) When these reactants come to equilibrium, assume that x mol H2 react. How many moles of ammonia form?