This preview shows pages 1–3. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: byrne (cmb3744) H05: Equilibrium 2 mccord (51620) 1 This printout should have 15 questions. Multiplechoice questions may continue on the next column or page find all choices before answering. 001 10.0 points A 2.000 liter vessel is filled with 4.000 moles of SO 3 and 6.000 moles of O 2 . When the reaction 2 SO 3 (gas) 2 SO 2 (gas) + O 2 (gas) comes to equilibrium a measurement shows that only 1.000 mole of SO 3 remains. How many moles of O 2 are in the vessel at equilib rium? 1. 7.000 mol 2. 7.500 mol correct 3. None of these is correct. 4. 12.000 mol 5. 3.750 mol Explanation: Initially, [SO 3 ] = 4 mol 2 L = 2 M [O 2 ] = 6 mol 2 L = 3 M 2 SO 3 (g) 2 SO 2 (g) + O 2 (g) ini, M 2 3 , M 2 x 2 x x eq, M 2 2 x 2 x 3 + x At equilibrium, [SO 3 ] eq = 1 mol 2 L = 0 . 5 M, so 2 2 x = 0 . 5 2 x = 1 . 5 x = 0 . 75 Thus [O 2 ] = 3 + x = 3 . 75 M mol O 2 = (3 . 75 mol / L) (2 L) = 7 . 5 mol . 002 10.0 points Suppose the reaction A B has an equilibrium constant of 1.0 and the ini tial concentrations of A and B are 0.5 M and 0.0 M, respectively. Which of the following is the correct value for the final concentration of A? 1. 0.250 M correct 2. None of these is correct. 3. 1.50 M 4. 1.00 M 5. 0.500 M Explanation: K = 1 . [A] ini = 0 . 5 M [B] ini = 0 M A B ini, M 0.5 0.0 , M x x eq, M . 5 x x K = [B] [A] = 1 . x . 5 x = 1 . x = 0 . 25 M [A] = 0 . 5 x = 0 . 25 M 003 10.0 points Suppose the reaction H 2 (g) + I 2 (g) 2 HI(g) has an equilibrium constant K c = 49 and the initial concentration of H 2 and I 2 is 0.5 M and HI is 0.0 M. Which of the following is the correct value for the final concentration of HI(g)? 1. 0.599 M byrne (cmb3744) H05: Equilibrium 2 mccord (51620) 2 2. 0.778 M correct 3. 0.250 M 4. 0.389 M 5. 0.219 M Explanation: K c = 49 [H 2 ] ini = 0 . 5 M [I 2 ] ini = 0 . 5 M [HI] ini = 0 M H 2 (g) + I 2 (g) 2 HI(g) Ini, M 0.5 0.5 , M x x +2 x Equil, M 0 . 5 x . 5 x 2 x K c = [HI] 2 [H 2 ] [I 2 ] 49 = (2 x ) 2 (0 . 5 x ) 2 7 = 2 x . 5 x 7(0 . 5 x ) = 2 x 3 . 5 7 x = 2 x 3 . 5 = 9 x x = 3 . 5 9 = 0 . 389 M Looking back at our equilibrium values, we see that the final concentration of HI is equal to 2 x , so 2(0.389) = 0.778 M. 004 10.0 points At T = 600 C, K c = 1 for the gasphase reaction A + B C + D Starting with 1 . 98 moles each of A and B in a 5.00 liter container, what will be the equilib rium concentration of C at this temperature? Correct answer: 0 . 198 M. Explanation: [A] = 1 . 98 mol 5 L = 0 . 396 M T = 600 C [B] = 1 . 98 mol 5 L = 0 . 396 M K c = 1 A + B C + D ini, M . 396 . 396 , M x x x x eq, M . 396 x . 396 x x x [C][D] [A][B] = 1 x 2 (0 . 396 x ) 2 = 1 x . 396 x = 1 x = 0 . 396 1 x x = [C] = 0 . 198 M 005 10.0 points The system H 2 (g) + I 2 (g) 2 HI(g) is at equilibrium at a fixed temperature with...
View Full
Document
 Spring '10
 McCord
 Equilibrium, Mole

Click to edit the document details