Chemistry 10: Equilibrium—General Name __________________________A. The Equilibrium State (15.1 to 15.6)

1. N2O4(g) 2 NO2(g)

a. reversible because reactants and products are confined in same state and Ea ≈ Ea’

b. reaction rates change as [R] and [P] change until ratef = kf[N2O4] = rater = kr[NO2]2

EQUAL REACTION RATES NOT CONCENTRATIONSc. law of mass action:

1. K = kf/kr = [NO2]2/[N2O4]2. K = [Products]/[Reactants]3. liquid and solid are not included in expression

because [ ] can’t change (part of K)4. same as “Q” in Nernst equation

2. equilibrium constant, Ka. unit-less quantityb. independent of original concentrationsc. depends on temperatured. Kc vs. Kp for gaseous systems

1. concentration in mol/L, then Kc

2. concentration in atm, then Kp

3. Kp = Kc x (RT)n(gas)—R = 0.0821e. size of K and the reactant/product balance

1. large K, means [products] > [reactants]2. small K, means [products] < [reactants]

f. if reaction is written backwards, then: K' = K-1

g. if coefficient x factor "n", then K’' = Kn

h. combining reactions to form a new equilibrium 2 NOBr(g) 2 NO(g) + Br2(g) K1

Br 2( g ) + Cl 2( g ) 2 BrCl( g ) K 2

2 NOBr(g) + Cl2(g) 2 NO(g) + 2 BrCl(g) K1 x K2

i. K, Go and Eo

1. equilibrium: G = E = 0, but Go and Eo 02. "o" [ ] = 1 M and P = 1 atm (not always 298 K)3. Go = -RTlnK and Eo = (RT/nF)lnK

(R = 8.31, T in K, n = moles e-, F = 96,500)4. when K > 1, then Go < 0, and Eo > 0

3. equilibrium problemsa. determine direction ( or from [ ]o

substitute [ ]o into equilibrium expression = Q if Q > K, then , if Q < K, then

b. determine K, given [ ]E

write expression from equation substitute [ ]E, solve for K

c. determine K, given [ ]o and one [ ]E set up an "ICE Box" (shaded boxes are given)

o I is initial concentrationo C is change in concentrationo E is equilibrium concentration

[ ] A + 2 B C + 3 DI [A]o [B]o [C]o [D]o

C -x -2x [C]E – [C]o = x 3xE [A]o - x [B]o – 2x [C]E [D]o + 3x

write expression from balanced equation substitute [ ]E , solve for K

d. determine one [ ]E, given other [ ]E and K write expression from equation substitute given [ ]E and K, solve for missing [ ]E

e. determine [ ]E, given [ ]o and K set up an "ICE Box" (shaded boxes are given)

[ ] A + 2 B C + 3 DI [A]o [B]o [C]o [D]o

C -x -2x +x +3xE [A]o – x [B]o – 2x [C]o + x [D]o + 3x

write expression from balanced equation substitute [ ]E and K, solve for x substitute x back into formulas solve for [ ]E

B. Le Chatelier's Principle (15.7)1. when a system at equilibrium is disturbed, the system

shifts ( or ) to minimize the disturbance 2. determine response using Le Chatelier’s principle

a. adding reactant or product: system shifts away from added species (K is unchanged)1. increase [R]: Q < K shifts to the right

a. increase [ ]E of products + added reactantb. decrease [ ]E of other reactants c. example: 3 H2(g) + N2(g) 2 NH3(g)

2. increase [P]: Q > K shifts to the leftb. removing reactant or product: system, shifts toward

removed species (K is unchanged)1. decrease [R]: Q > K shifts to the left2. decrease [P]: Q < K shifts to the right

c. change temperature: system shifts to restore equilibrium temperature (K changes)1. increase T: initial rateendo > initial rateexo

(shifts toward +H or away from –H)2. decrease T: initial rateendo < initial rateexo

(shifts toward –H or away from +H)3. predict change in K

a. shifts to the right K increasedb. shift to the left K decreased

d. change volume of the container: system shifts to restore equilibrium [ ]gases (K is unchanged)1. ngas reactant > ngas product

a. increase V decreases [ ]gases: Q > Kshifts to the left (toward more gas)

b. decrease V increases [ ]gases: Q < K shifts to the right (toward less gas)

2. ngas reactant < ngas producta. increase V decreases [ ]gases: Q < K

shifts to the right (toward more gas)b. decrease V increases [ ]gases: Q > K

shifts to the left (toward less gas)3. ngas reactants = ngas product: Q = K

system is unresponsive e. adding species that are neither reactants or

products has no effect on equilibrium1. catalyst (affect both rates equally)2. inert substances ([ ] and T are unaffected)

Experiments1. Equilibrium Constant Lab—Mix reactants, measure the

color of the equilibrium state to determine the equilibrium concentrations and calculate Kc.Fill each of five cuvette tubes with the number of drops of 0.00200 M Fe(NO3)3 in 1 M HNO3, 0.00200 M KSCN, and

distilled water listed in the table below. Cuvette 1 2 3 4 5

drops H2O 32 24 16 8 0drops

Fe(NO3)340 40 40 40 40

drops KSCN 8 16 24 32 40Mix each solution by placing the rubber dam over the cuvette mouth and turning the tube upside down. Measure the absorbance (Abs) using the spectrophotometer.a. Determine [Fe3+]o, [SCN-]o, and [FeSCN2+]E.

[Fe3+]o x 10-3 [SCN-]o x 10-3 Abs(447 nm)

[FeSCN2+]E x 10-3

2 x (# d/80) 0.11 x Abs

1

1.00

2

3

4

5

b. Complete the "ICE" Boxes to determine [Fe3+]E and [SCN-]E. Calculate Kc for each cuvette.[ ]

Fe3+ + SCN- FeSCN2+

1

IC

EKc

2

IC

EKc

3

IC

E

K

c

4

IC

EKc

5

IC

EKc

c. Determine the % deviation between the five cuvettes by completing the chart.

1 2 3 4 5Kc

mean

absolute average

% 2. Le Chatelier's Principle Lab—Predict how stress will shift the

following equilibrium based on Le Chatelier's Principle and compare the prediction to the observed changes.

Co(H2O)62+(aq) + 4 Cl-(aq) CoCl4-(aq) + 6 H2O(aq)

pink bluea. The equilibrium system is endothermic. Predict how the

system will respond to the following stress in terms of color change.

Color Change

AddCl-

Add H2O

Add Heat

Remove Heat

Pink (shift to the left)

Blue (shift to the right)

b. Perform the procedure step. Indicate the color shift (toward pink = shift to the left or toward blue = shift to the right). Justify your observations using Le Chatelier's Principle.

Procedure(Start with 20 drops) Color Shift Match

Prediction?Add 10 drops of 12 M HCl and note the color shift.Add 10 drops of H2O and note the color shiftPlace the tube in boiling hot water for 30 s and note the color shift.Place the tube in ice cold water for 30 s and note the color shift.

Practice ProblemsA. The Equilibrium State

1. Write equilibrium expressions for the following gas systems.

2 SO2(g) + O2(g) 2 SO3(g)

Ni(s) + 4 CO(g) Ni(CO)4(g)

4 NH3(g) + 7 O2(g) 4 NO2(g) + 6 H2O(g)

2. The following represents the equilibrium: A B. Initially the container (on the left) holds pure A. Each frame represents 1 minute of time.

0 min 1 min 2 min 3 min 4 minA A A A A A A A A A

A A A A B AB A A A

A B A A B A B A A B

A B B A B A B B A B

A B B B A A B A B B

a. At what time does the system reach equilibrium?

b. Calculate the equilibrium constant, K.

3. The following results were collected for the equilibrium: 2 SO2(g) + O2(g) 2 SO3(g) for different initial [ ]o.

Experiment 1 Experiment 2[ ]o [ ] [ ]o [ ]

SO2 2.00 M 1.50 M 0.500 M 0.590 MO2 1.50 M 1.25 M 0 M 0.0450 MSO3 3.00 M 3.50 M 0.350 M 0.260 Ma. Write the equilibrium expression for the reaction

b. Calculate K for experiment 1.

c. Calculate K for experiment 2.

4. For the reaction: N2(g) + 3 F2(g) 2 NF3(g) at equilibrium, PN2 = 0.021 atm, PF2 = 0.063 atm and PNF3 = 0.48 atm.a. Calculate Kp.

b. Determine the equilibrium concentrations of N2, F2 and NF3 in mol/L at 25oC.

c. Calculate Kc.

d. Calculate Kp using the equation, KP = Kc x (RT)ng.

5. The following represents the system reaching equilibrium.A2(g) + B(g) A2B(g)

AA B AA AA B AA B BAA B

AAB AA

AAB B AAB AAB

a. Calculate Kc.

b. Calculate Kp at 25oC.

6. Given the following Kc values, calculate the corresponding values of Kp at 298 K.a. CO2(g) + H2(g) CO(g) + H2(g) Kc = 0.0431

b. 2 SO3(g) 2 SO2(g) + O2(g) Kc = 3.2 x 10-4

7. 2 SO2(g) + O2(g) 2 SO3(g) Kc = 0.120What are the equilibrium constants for the following?a. SO2(g) + ½ O2(g) SO3(g)

b. 2 SO3(g) 2 SO2(g) + O2(g)

8. 2 SO2(g) + O2(g) 2 SO3(g) Kc = 56Calculate Kc fora. SO3(g) SO2(g) + ½ O2(g)

b. 4 SO2(g) + 2 O2(g) 4 SO3(g)

9. Given the following data at 25oC2 NO(g) N2(g) + O2(g) Kc = 1 x 1030

2 NO(g) + Br2(g) 2 NOBr(g) Kc = 2 x 103

Calculate Kc for the reaction: N2(g) + O2(g) + Br2(g) 2 NOBr(g)

10. Given: H2(g) + S(s) H2S(g) Kc = 1.0 x 10-3

S(s) + O2(g) SO2(g) Kc = 5.0 x 106 calculate Kc for the reaction:

H2(g) + SO2(g) H2S(g) + O2(g).

11. Cl2(g) 2 Cl(g) Kpo is 1.0 x 10-37

Calculate Go for the above reaction.

12. 2 SO2(g) + O2(g) 2 SO3(g) Kpo = 2.3

a. What is Go?

b. What is Eo?

13. Given the following data at 25oC2 NO(g) + Br2(g) 2 NOBr(g) Kc = 1002 NO(g) N2(g) + O2(g) Kc = 0.50

a. What is Kc for the following equilibrium?N2(g) + O2(g) + Br2(g) 2 NOBr(g)

b. What is Kp at 25oC?

c. What is Go for the equilibrium at standard conditions?

14. COCl2(g) CO(g) + Cl2(g) Kc = 1.0 x 10-5

What direction will the reaction proceed if 2.0 x 10-3 M COCl2, 3.3 x 10-6 M CO, and 6.6 x 10-6 M Cl2 are mixed?

15. The following represents three initial states for the system: A2 + B2 2 AB (Kc = 1.5). Indicate the direction that the system proceeds from its initial state to reach equilibrium.

ABBB AB AB AB AB AB AA

AA AB AB BB

AAAA AB BB

AABB

BB AB

BB AA AA AB

16. N2(g) + O2(g) 2 NO(g) Kc = 6.2 x 10-4 What is the initial direction of reaction when 0.052 mol N2, 0.0124 mol O2, and 0.0020 mol NO are added to a 5 L flask?

17. H2(g) + CO2(g) H2O(g) + CO(g)[H2] = 0.61 M, [CO2] = 1.6 M, [H2O] = 1.1 M and [CO] = 1.4 M. Calculate Kc.

18. Br2(g) 2 Br(g)Given the equilibrium concentration: [Br2] = 0.97 M and [Br] = 0.034 M, calculate Kc.

19. A(g) B(g) + 2 C(g). Complete the chart, then calculate Kc for the equilibrium.[ ] A B + 2 CI 0.75 0.0 0.0CE 0.30

20. SO2(g) + ½ O2(g) SO3(g)0.012 moles of O2 and 0.027 moles of SO2 are placed in a sealed one-liter container. At equilibrium, the concentration of SO3 is 0.020 M. Calculate Kc.

[ ]ICE

21. 2 NOCl(g) 2 NO(g) + Cl2(g)At 220oC in a sealed flask, initial concentrations are 0.520 M NOCl, 0.010 M NO, and 0.053 M Cl2. At equilibrium is 4.23% of the NOCl is decomposed. Calculate Kc.

[ ]ICE

22. 2 NO(g) + Br2(g) 2 NOBr(g)0.100 mol NO and 0.050 mol Br2 are placed in a 1.0-L flask. At equilibrium [NOBr] = 0.060 M. Calculate Kc.[ ]ICE

23. H2(g) + I2(g) 2 HI(g) 0.200 mol H2 and 0.100 mol I2 are placed in a 2.0-L flask. At equilibrium, 48.0 % of the H2 is consumed. Calculate Kc.[ ]ICE

24. 2 NO(g) + 2 H2(g) N2(g) + 2 H2O(g)The initial concentrations are 0.100 M NO, 0.050 M H2, and 0.100 M H2O. At equilibrium [NO] = 0.070 M.

a. Calculate the [H2]E, [N2]E, and [H2O]E.[ ]ICEb. Calculate Kc.

25. The following represents the system: A2 + B A + AB. AA A AA AB AB AB A ABGiven Kp = 2, how many Bs should be added to the diagram in order to represent equilibrium?

26. 2 BrCl(g) Br2(g) + Cl2(g) Kc = 0.040What is [BrCl] when [Cl2] = [Br2] = 0.0325 M?

27. 2 N2O(g) + O2(g) 4 NO(g) Kc = 2.9 x 10-26

What is [NO] when [N2O] = 0.0035 M and [O2] = 0.0027 M?

28. N2(g) + 3 H2(g) 2 NH3(g) Kp = 1.5 x 10-5

At equilibrium PN2 = 0.40 atm, PH2 = 0.10 atm, what is PNH3?

29. H2(g) + I2(g) 2 HI(g) Kc = 81 What are the equilibrium concentrations of the three gases?[ ] H2 + I2 2 HII 0.50 0.50 0CE

30. 2 HI(g) H2(g) + I2(g) Kc = 0.012[HI]o = 0.050 M, [H2]o = [I2]o = 0.100 M. What are the equilibrium concentrations of all species?[ ]ICE

31. SO2(g) + NO2(g) NO(g) + SO3(g) Kc = 85What will be the equilibrium concentrations of the four gases if the initial concentrations of SO2 and NO2 are 0.075 M?[ ]ICE

32. PCl5(g) PCl3(g) + Cl2(g) Kc = 0.050A sealed 4.0-L vessel initially contains 0.025 mol PCl5. a. What are the equilibrium concentrations of all species?

[ ]ICE

b. What is the equilibrium pressure at 250oC?

B. Le Chatelier's Principle33. Determine the shift in an equilibrium system when it is

stressed using Le Chatelier's principle.Condition Stress Shift (, ) Change K

All

Reactant Reactant Product Product

Exothermic Temperature Temperature

Endothermic Temperature Temperature

2 A(g) B(g) Volume Volume

A(g) 2 B(g) Volume Volume

A(g) B(g) Volume Volume

All Add Inert Gas34. Consider the reaction: 2 SO2(g) + O2(g) 2 SO3(g).

a. What is H? (Hfo

SO2 = -296.8 kJ, Hfo

SO3 = -395.7 kJ)

b. How will each shift the equilibrium and change K?Change Equilibrium shift Change KAdd O2

Remove SO3

Increase VAdd He(g)Increase T

35. The following represents the system: A2 + B A + AB at 300 K (left side) and 500 K (right side). Is this an exothermic or endothermic process? Explain your reasoning.

300 K 500 KB A B AB AA AA AAAB B AB

AB AB AB A A ABA AA AB B

Questions 36-38 Indicate the direction ( or ) that the equilibrium system will shift in response to each disruption.

36. A(g) + 2 B(g) + Heat C(g) + D(g)Disruption Response

Chemical A is addedChemical C is taken awayTemperature is increasedVolume is decreased

37. A(g) + B(g) 2 C(g) + 3 D(g) + HeatDisruption Response

Chemical A is removedChemical C is addedTemperature is decreasedVolume is decreased

38. 3A(g) + Heat 2 C(g) + D(g)Disruption Response

Chemical A is removedChemical C is addedTemperature is decreasedVolume is decreased

Practice Multiple ChoiceBriefly explain why the answer is correct in the space provided.Questions 1-10. Consider the equilibrium: 2 A(g) B(g) + C(g).1. Which is the correct equilibrium expression?

(A) K = [B][C]/[A]2 (B) K = [A]2/[B][C](C) K = [B][C] – [A] (D) K = [A]2 + [B][C]

2. Calculate Kc at 25oC given the equilibrium concentrations: [A] = 0.50 M, [B] = 1.0 M, and [C] = 4.0 M.(A) 8.0 (B) 0.013 (C) 200 (D) 16

3. Calculate Kp for the equilibrium at 25oC.(A) 4.5 (B) 2000 (C) 8.0 (D) 16

4. Calculate Go for the equilibrium at 25oC when all the species are at 1 atm partial pressure.(A) -(0.0821)(298)lnK (B) -(8.31)(298)lnK(C) (8.31)(298)lnK (D) -(8.31)(25)lnK

5. In another experiment 1.0 mol of B and 1.0 mol of C are placed in an evacuated 1.0-L vessel at 25oC. What is the concentration of A after equilibrium is established?(A) 0.050 M (B) 0.11 M (C) 0.22 M (D) 0.35 M

6. 1.0 M A is placed in a vessel at 100oC. At equilibrium, [C]E = 0.40 M. What is the equilibrium concentration of A?(A) 0.20 M (B) 0.55 M (C) 0.40 M (D) 0.90 M

7. What is Kc at 100oC?(A) 0.25 (B) 4.0 (C) 16 (D) 2.0

8. Which of the following is correct concerning this equilibrium?

(A) The forward reaction is exothermic because raising temperature favors the exothermic reaction.

(B) The forward reaction is endothermic because raising temperature favors the exothermic reaction.

(C) The forward reaction is exothermic because raising temperature favors the endothermic reaction.

(D) The forward reaction is endothermic because raising temperature favors the endothermic reaction.

9. Which is correct concerning this equilibrium?(A) Increase [A] shifts the equilibrium to the left.(B) Increase [B] shifts the equilibrium to the right.(C) Decrease [C] shifts the equilibrium to the left.(D) Increasing the volume has no effect on the equilibrium.

10. What is Kc at 25oC for the equilibrium A(g) ½ B(g) + ½ C(g)?

(A) 4.0 (B) 0.063 (C) 8.0 (D) 260

11. Which must be true for an equilibrium initially at standard state that proceeds spontaneously in the forward direction?(A) Go > 0 and Keq > 1 (B) Go > 0 and Keq < 1(C) Go < 0 and Keq > 1 (D) Go < 0 and Keq < 1

12. The equilibrium constant for a reaction is 200. What is K for the reverse reaction at the same temperature? (A) -200 (B) -0.005 (C) 0.002 (D) 0.005

13. 4 HCI(g) + O2(g) 2 Cl2(g) + 2 H2O(g)Equal moles of HCI and O2 are added to an evacuated vessel. Which must be true for the system at equilibrium?(A) [HCI] < [Cl2] (B) [HCI] > [Cl2] (C) [HCl] > [O2]. (D) [Cl2] = [H2O]

14. Cu + 2 Ag+ Cu2+ + 2 AgIf the equilibrium constant is 3.7 x 1015, which of the following correctly describes the standard voltage, Eo, and the standard free energy change, Go, for this reaction?(A) Eo > 0 and Go < 0 (B) Eo < 0 and Go > 0(C) Eo > 0 and Go > 0 (D) Eo < 0 and Go < 0

15. For the reaction A(g) B(g) + C(g), Kp, = 2 x 10-4 at 25oC. A mixture of the three gases at 25oC is placed in a flask and the initial pressures are PA = 2 atm, PB = 0.5 atm, and PC = 1 atm. Which is true at the instant of mixing?(A) G < 0 (B) G > 0 (C) S = 0 (D) Go = 0

16. CuO + H2(g) Cu + H2O H = -2.0 kJThe equilibrium can be shifted to favor the products by (A) increasing the volume at constant temperature.(B) increasing the pressure by adding an inert gas.(C) decreasing the temperature.(D) releasing H2(g) at constant pressure and temperature.

17. 2 SO3(g) 2 SO2(g) + O2(g)

After equilibrium is established, some pure O2(g) is injected into the reaction vessel at constant temperature. After equilibrium is reestablished, which of the following has a lower value compared to its original equilibrium value? (A) Keq for the reaction (B) The amount of SO3(g) in the reaction vessel(C) The amount of O2(g) in the reaction vessel(D) The amount of SO2(g) in the reaction vessel

18. 2 NO(g) + O2(g) 2 NO2(g) H < 0Which of the following changes alone would cause a decrease in the value of Keq for the reaction above? (A) Decreasing the temperature(B) Increasing the temperature (C) Decreasing the volume of the reaction vessel(D) Increasing the volume of the reaction vessel

19. 2 SO2(g) + O2(g) 2 SO3(g) When 0.40 mole of SO2 and 0.60 mole of O2 are placed in an evacuated 1.00 L flask. After reaching equilibrium the flask contains 0.30 mole of SO3. Kc, is (A) (0.30)2/(0.45)(0.10)2 (B) (0.30)2/(0.60)(0.40)2 (C) (0.60)/(0.45)(0.20) (D) (0.30)/(0.45)(0.10)

Practice Free Response1. Given:

2 NO(g) + Br2(g) 2 NOBr(g) Kc = 2.0 2 NO(g) N2(g) + O2(g) Kc = 2.1 x 1030

What is Kc for the following equilibrium?N2(g) + O2(g) + Br2(g) 2 NOBr(g)

2. The equilibrium constant for the reaction is Kc = 2.19 x 10-10.COCl2(g) CO(g) + Cl2(g)

Is a mixture containing 2.0 x 10-3 M COCl2, 3.3 x 10-6 M CO, and 6.6 x 10-6 M Cl2 at equilibrium? If not, what direction will the reaction proceed to achieve equilibrium?

3. Consider the equilibrium at 25oC: A(g) + B(g) 2 C(g).a. Write the equilibrium expression for this equilibrium.

b. Calculate Kc at 25oC given [A]E = 0.025 M, [B]E = 0.100 M, and [C]E = 0.500 M.

c. Calculate Kp for the equilibrium at 25oC.

d. State which direction the equilibrium will shift (, ) to relieve the following stresses on the system.

Increase V Increase P Increase [A]

e. What is Kc at 25oC for C(g) ½ A(g) + ½ B(g)?

f. Calculate Go for the equilibrium at 25oC when all the species are at 1 atm partial pressure.

g. In another experiment 1.00 mol of A and 1.00 mol of B are placed in an evacuated 1.00-L vessel at 25oC.

What are the concentrations of the three gases after equilibrium is established?

[ ]ICE

h. A mixture of 1.00 M A and 0.50 M B are placed in a vessel at 100oC. At equilibrium, [C] = 0.90 M. What are the equilibrium concentrations of A and B?

[ ]ICEi. What is Kc at 100oC?

j. Is the forward reaction endothermic or exothermic. Explain your reasoning.

4. N2(g) + 3 H2(g) 2 NH3(g) Kp = 1.45 x 10-5

What is the partial pressure of NH3 if the partial pressures of N2 and H2 are 0.432 atm and 0.928 atm respectively?

5. H2(g) + CO2(g) H2O(g) + CO(g)When H2 is mixed with CO2 at 2,000 K, equilibrium is achieved according to the equation. In one experiment, the following equilibrium concentrations were measured. [H2] = 0.20 M, [CO2] = 0.30 M, [H2O] = [CO] = 0.55 Ma. Calculate the value of Kc.

b. Determine Kp in terms of Kc for this system.

c. When the system is cooled to a lower temperature, 30.0 percent of the CO is converted back to CO2. (1) Calculate the change in [CO]

(2) Calculate Kc at this lower temperature.[ ]ICE

d. In a different experiment, 0.500 mole of H2 is mixed with 0.500 mole of CO2 in a 3.00-liter vessel at 2,000 K. (1) Calculate the initial concentration of H2 and CO2.

(2) Calculate the equilibrium concentrations.[ ]ICE

6. Answer the following questions regarding the decomposition of arsenic pentafluoride, AsF5(g).

a. A 55.8 g sample of AsF5(g) is introduced into an evacuated 10.5 L container at 105oC. (1) What is the initial molar concentration of AsF5(g)?

(2) What is the initial pressure, in atmospheres, of the AsF5(g) in the container?

At 105oC, AsF5(g) decomposes into AsF3(g) and F2(g) according to the following chemical equation.

AsF5(g) AsF3(g) + F2(g)b. In terms of molar concentrations, write the equilibrium-

constant expression for the decomposition of AsF5(g).

c. When equilibrium is established, 27.7 percent of the original number of moles of AsF5(g) has decomposed.(1) Calculate the molar concentration of AsF5(g) at

equilibrium.

(2) Using molar concentrations, calculate the value of the equilibrium constant, Keq, at 105oC.

d. Calculate the mole fraction of F2(g) in the container at equilibrium.

7. Consider bromine chloride. It is formed by the reaction between red-orange bromine vapor and yellow chlorine gas; BrCl is itself a gas. The reaction is endothermic.a. Write the chemical equation for the formation of BrCl,

using simplest whole-number coefficients.

b. Write the equilibrium expression for Kc.

c. At 400oC, after the reaction reached equilibrium, the mixture contained 0.82 M BrCl, 0.20 M Br2 and 0.48 M Cl2. Calculate Kc for the reaction.

d. What is Kp at 400oC?

e. Initially, a 2.00-L flask contains Cl2 with partial pressure 0.51 atm and Br2 with partial pressure 0.34 atm. After equilibrium is established, the partial pressure of BrCl is 0.46 atm. Calculate the equilibrium pressures of Cl2 and Br2.

f. Initially, a 1.00-L flask contains 0.15 mol of each gas. What are the equilibrium concentrations of each gas at 400oC?

g. In what direction will the system shift if at equilibrium?the volume is increased?helium gas is added?the temperature is increased?