REVIEW QUESTIONS Chapter 15

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1 hemistry 10 ANSWER EY REVIEW QUESTIONS hapter A mixture of 0.10 mol of NO, mol of H and 0.10 mol of HO is plaed in a 1.0-L flask and allowed to reah equilibrium as shown below: NO (g) + H (g) N (g) + HO (g) At equilibrium [NO] = 0.06 M. alulate the equilibrium onstant,, for this reation. NO + H (g) N (g) + HO (g) Initial 0.10 M M M Equilibrium [N ][H O] (0.019)(0.18) = = = 650 [NO] [H ] (0.06) (0.01). At 700, = 0.4 for the reation shown below: (A) SO (g) + ½ O (g) SO (g) alulate and P for the reation shown below: (B) SO (g) + O (g) SO (g) (B) = [ (A)] = (0.4) = 416 P = (RT) n = (416) [(0.081)(97 )] 1 = 5.1. At 100, = for the following reation: SOl (g) SO (g) + l (g) In an equilibrium mixture, [SOl] = 0.16 M and [SO] = 0.07 M. What is the onentration of l in the equilibrium mixture? [SO ][l ] = = [SOl ] [SO l ] (0.078)(0.16) [l ] = = = 0.15 M [SO ]

2 4. At 7, P= for the equilibrium: NOBr (g) NO (g) + Br (g) If the partial pressures of NOBr and NO are equal at equilibrium, what is the partial pressure of Br? P P = = sine P = P P NO Br p NOBr NO PNOBr Br = atm 5. A mixture of mol O, mol H and mol HO are plae in a 1.00-L flask and allowed to ome to equilibrium as shown below. At equilibrium [O] = M. O (g) + H (g) O (g) + HO (g) a) What are the equilibrium onentrations of H, O and HO? O (g) + H (g) O (g) + HO (g) Initial Equilibrium b) alulate and p for this reation at 5.0. [O][H O] (0.0046)(0.1046) = = = 0.11 [O ][H ] (0.0954)(0.0454) n 0 p = (RT) = 0.11 [(0.081)(98)] = 0.11

3 6. When.00 mol eah of hydrogen and iodine are mixed in a 1.00-L flask,.50 mol of HI is produed at equilibrium: H (g) + I (g) HI (g) alulate the equilibrium onstant for this reation. H (g) + I (g) HI (g) Initial.00 M.00 M Equilibrium [HI] (.50) = = = 196 [H ] [I ] (0.5) 7. The equilibrium onstant for the reation SO (g) + NO (g) SO (g) + NO (g) has a numerial value of.00 at a given temperature mol eah of SO and NO are mixed in a 1.00-L flask and allowed to reah equilibrium. What perent of SO is onverted to produt? SO (g) + NO (g) SO (g) + NO (g) Initial 1.50 M 1.50 M 0 0 x x + x + x Equilibrium 1.50 x 1.50 x x x [SO ][NO] x = = =.00 [SO ][NO ] ( x) x = x x x =.595 x = % = x100 = 6.4% 1.50

4 8. The following equilibrium exists at 1000 º with =.00. OF (g) O (g) + F4 (g) If a 5.00-L mixture ontains mol OF, 0.6 mol of O and mol of F4 at 1000 º, in whih diretion will the mixture proeed to reah equilibrium? mol 0.6 mol [OF ] = = M [O ] = = M 5.00 L 5.00 L mol [F 4] = = M 5.00 L [O ][F 4] (0.054)(0.0148) Q = = = 0.9 [OF ] (0.090) Sine Q <, reation will proeed in the forward diretion 9. A 0.81-g sample of SO is plaed in a 1.00-L flask and heated to The SO deomposes to SO and O, as shown below. At equilibrium, the total pressure in the ontainer is 1.00 atm. Find the values of p and for this reation at SO (g) SO (g) + O (g) 1 mol mol SO = 0.81 g x = mol g nrt (0.0108)(0.081)(1100 ) P SO = = = atm V 1.00 L tot SO SO O tot SO (g) SO (g) + O (g) Initial x + x + x Equilibrium x x x P = P + P + P = 1.00 atm P = (0.974-x) + x + x = 1.00 atm x = P = 0.66 atm P = P = 0.75 atm P = x = 0.1 atm O SO O P P (0.75) (0.66) = = = 4. (0.1) SO O p PSO p 4. = = = n 1 (RT) [(0.081)(1100)] 4

5 10. Predit how eah of the following hanges affet the amount of H present in an equilibrium mixture in the reation Fe (s) + 4 HO (g) FeO4 (s) + 4 H (g) H = 150 kj a) Raising the temperature of the mixture. Sine reation is exothermi, raising temperature will shift the equilibrium to the left ( ) and redue amount of hydrogen. b) Adding more HO (g). Adding more water, will shift the equilibrium to the right ( ) and inrease the amount of hydrogen. ) Doubling the volume of the ontainer holding the mixture. Inreasing the volume of the ontainer will redue the pressure but the equilibrium will not be affeted, and the amount of hydrogen will not hange. d) Adding a atalyst. Adding atalyst does not alter the equilibrium and the amount of hydrogen produed. 11. At 000 the equilibrium onstant for the reation below is =.4x10. If the initial onentration of NO is M, what are the equilibrium onentrations of eah substane? NO (g) N (g) + O (g) NO (g) N (g) + O (g) Initial M 0 0 x + x + x Equilibrium x x x [N ][O ] x = = =.4x10 [NO] ( x) x = 49 [N ] = [O ] = x = 0.5 M x x + 98 x = 4.5 [NO] = x = x = [NO] = 6.0 x 10 M 5

6 1. The reation below has an equilibrium onstant = If mol of Brl is plaed in a 500-mL flask and allowed to ome to equilibrium, what are the equilibrium onentrations of eah substane? Br (g) + l (g) [Brl] = mol/0.500 L= 0.00 M Brl (g) Br (g) + l (g) Brl (g) Initial M +x + x x Equilibrium x x 0.00 x [Brl] ( x) = = = 6.90 [Br ][l ] (x) x =.6 [Br ] = [l ] = x = 0.04 M x.6 x + x = 0.00 [Brl] = x = x = 0.04 [Brl] = M 1. An equilibrium mixture of H, I, and HI at 458 ontains.4x10 M H,.4x10 M I and M HI in a 5.00-L flask. What are the equilibrium onentrations when equilibrium is reestablished following the addition of mol of HI? [HI] (0.155) H (g) + I (g) HI (g) = = = [H ] [I ] (.4x10 ) After addition of mol HI: [HI] = M M) = M H (g) + I (g) HI (g) Initial.4x10 -.4x x +x x Equilibrium (.4x10 - )+x (.4x10 - )+x x [HI] (0.175-x) = = = [H ][I ] [(.4x10 )+x] x - (.4x10 )+x = x = x 8.9x = 0.00 x = [H ] = [I ] =.46x10 M [HI] = M 6