Mar 20 8:48 AM. The equilibrium constant is dependent on temperature.

Transcription

1 certain reaction that has the equilibrium equation (g) + (g) 2(g) has an equilibrium constant value of.455 at 293 K. If 2.00 moles of, 2.00 moles of and 3.00 moles of are placed in a 1.00 L vessel at 293, what will the equilibrium concentration of be? Mar 20 8:48 M 1 Which of the following statements about chemical equilibrium are not true? The equilibrium constant is dependent on temperature. The equilibrium constant is independent of the concentrations of reactants or products at certain reaction conditions. The initial concentrations of reactants and products will affect the equilibrium position. When starting with only reactants, only the forward reaction will take place until equilibrium is reached. When starting with only the products, the reverse reaction rate will exceed the forward reaction rate until equilibrium is reached. 1

2 2 Which of the following is the correct chemical reaction for the following law of mass action? (s) + (g) 2 (g) + (g) 2(s) + (g) 2 (s) + (g) 2(g) + (s) (s) + (g) K = [] 2 [] (s) + (g) 2(g) + (s) (g) + 2(g) 2 (g) + (g) 3 certain reaction that has the equation (g) + 2(g) 3(g) has a K value of X. What is the value of Kp at the same reaction conditions? X 2X X 2 square root of X 2X 2 2

3 4 Which of the following statements are true for a reaction with a very small equilibrium constant? The equilibrium position lies far to the right. The equilibrium position lies far to the left. The reaction will proceed rapidly to the equilibrium position upon the combination of reactants. The reaction will proceed slowly to the equilibrium position upon the combination of reactants. Two of the above. 5 When 0.40 mole of SO 2 and 0.60 mole of O 2 are placed in an evacuated 1.00 liter flask, the reaction represented below occurs. fter the reactants and the product reach equilibrium and the initial temperature is restored, the flask is found to contain 0.30 mole of SO 3. ased on these results, the expression for the equilibrium constant, Kc, of the reaction is (0.30) 2 (0.45)(0.10) 2 2 SO 2(g) + O 2(g) 2SO 3(g) (0.30) 2 (0.60)(0.40) 2 (2 x 0.30) (0.45)(2 x 0.10) (0.30) (0.45)(0.10) (0.30) (0.60)(0.40) 3

4 6 The reaction (g) (g) has a K value of 3.2 x t equilibrium, which of the following would be true? [] = [] [] < [] [] > [] 7 The reaction 2(g) (g) has a K value of 4. What is the value of K for the reaction ½(g) (g)

5 8 The reaction 2(g) (g) has a K value of 4.0 when 2.00 mol of and 4.00 mol of are added to a 2.0 L vessel. What is the value of K when 2.00 mol of and 4.00 mol of are added to a 1.0 L vessel at the same temperature? The reaction H 2 (g) + I 2 (g) 2 HI(g) has a K value of 244 at a certain temperature. If the concentration of H 2 is M and I 2 is M at equilibrium, what is the concentration of HI at equilibrium? 0.95 M 0.55 M 0.12 M M M 5

6 10 t a 127 º the reaction 3H 2 (g) + N 2 (g) 2NH 3 (g) has a K of 3.8 x What is the value of K P at this temperature? When the substances in the equation below are at equilibrium at pressure P and temperature T, the equilibrium can be shifted to favor the products by uo(s) + H 2 (g) u(s) + H 2 O(g); ΔH = 2.0 kj increasing the pressure by means of a moving piston at constant T increasing the pressure by adding an inert gas such as nitrogen decreasing the temperature allowing some gases to escape at constant P and T adding a catalyst 6

7 12 onsider the equilibrium below. Which of the following changes will increase the concentration of HgI 4 2? Increasing the concentration of OH dding 6 M HNO 3 HgO(s) + 4 I + H 2 O HgI OH ; ΔH < 0 Increasing the mass of HgO present Increasing the temperature dding a catalyst 13 In which of the following systems would the number of moles of the substances present at equilibrium NOT be shifted by a change in the volume of the system at constant temperature? O(g) + NO(g) O 2 (g) + 1/2 N 2 (g) N 2 (g) + 3 H 2 (g) 2 NH 3 (g) N 2 (g) + 2 O 2 (g) 2 NO 2 (g) N 2 O 4 (g) 2 NO 2 (g) NO(g) + O 3 (g) NO 2 (g) + O 2 (g) 7

8 14 Some Pl 3 and l 2 are mixed in a container at 200 and the system reaches equilibrium according to the equation below. Which of the following causes an increase in the number of moles of Pl 5 present at equilibrium? I only II only I and III only Pl3(g) + l2(g) Pl5(g) + energy I. ecreasing the volume of the container II. Raising the temperature III. dding a mole of He gas at constant volume II and III only I, II, and III 15 Which of the following changes alone would cause a decrease in the value of Kc for the reaction represented below? ecreasing the temperature Increasing the temperature 2 NO(g) + O 2 (g) 2 NO 2 (g) ; ΔH < 0 ecreasing the volume of the reaction vessel Increasing the volume of the reaction vessel dding a catalyst 8

9 16 For the following reaction K P = 1.25 atm at 700. º. How many moles of will remain if 5.00 moles of (s) are placed into a 5.00 L vessel and heated to 700. º? nswers: =1.77M Mar 13 9:54 PM 9