Tro - Chemistry: A Molecular Approach 4th Edition - Chapter 15

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Ch.15 - Chemical Equilibrium

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Tro 4th Edition

Ch.15 - Chemical Equilibrium

Problem 31b,c
Calculate K_c for each reaction.
b. CH₄(g) + H₂O(g) ⇌ CO(g) + 3 H₂(g) K_p = 7.7x10²⁴ (at 298 K)
c. I₂(g) + Cl₂(g) ⇌ 2 ICl(g) K_p = 81.9 (at 298 K)
Problem 32a
Calculate K_p for each reaction. a. N₂O₄(g) ⇌ 2 NO₂(g) K_c = 5.9⨉10^-3 (at 298 K)
Problem 32b,c
Calculate K_p for each reaction.
b. N₂(g) + 3 H₂(g) ⇌ 2 NH₃(g) K_c = 3.7⨉10⁸ (at 298 K)
c. N₂(g) + O₂(g) ⇌ 2 NO(g) K_c = 4.10⨉10^-31 (at 298 K)
Problem 33
Write an equilibrium expression for each chemical equation involving one or more solid or liquid reactants or products: a. CO32-(aq) + H2O(l) ⇌ HCO3-(aq) + OH-(aq) b. 2 KClO3(s) ⇌ 2 KCl(s) + 3 O2(g) c. HF(aq) + H2O(l) ⇌ H3O+(aq) + F-(aq) d. NH3(aq) + H2O(l) ⇌ NH4+(aq) + OH-(aq)
Problem 34
Find and fix the mistake in the equilibrium expression. PCl5(g) ⇌ PCl3(l) + Cl2(g) Kc = [Cl2]/[PCl5]
Problem 35
Consider the reaction: CO(g) + 2 H2(g) ⇌ CH3OH(g). An equilibrium mixture of this reaction at a certain temperature has [CO] = 0.105 M, [H2] = 0.114 M, and [CH3OH] = 0.185 M. What is the value of the equilibrium constant (Kc) at this temperature?
Problem 36
Consider the reaction: NH4HS(s) ⇌ NH3(g) + H2S(g). An equilibrium mixture of this reaction at a certain temperature has [NH3] = 0.278 M and [H2S] = 0.355 M. What is the value of the equilibrium constant (Kc) at this temperature?
Problem 37
Consider the reaction: N₂(g) + 3 H₂(g) ⇌ 2 NH₃(g) Complete the table. Assume that all concentrations are equilibrium concentrations in M.
T (K) [N₂] [H₂] [NH₃] K_c
500 0.115 0.105 0.439 _
575 0.110 _ 0.128 9.6
775 0.120 0.140 _ 0.0584
Problem 38
Consider the following reaction: H₂(g) + I₂(g) ⇌ 2 HI(g) Complete the table. Assume that all concentrations are equilibrium concentrations in M.
T (°C) [H₂] [I₂] [HI] Kc
25 0.0355 0.0388 0.922 _
340 _ 0.0455 0.387 9.6
445 0.0485 0.0468 _ 50.2
Problem 39
Consider the reaction: 2 NO(g) + Br₂(g) ⇌ 2 NOBr(g) K_p = 28.4 at 298K In a reaction mixture at equilibrium, the partial pressure of NO is 108 torr and that of Br₂ is 126 torr. What is the partial pressure of NOBr in this mixture?
Problem 40
Consider the reaction: SO₂Cl₂(g) ⇌ SO₂(g) + Cl₂(g) K_p = 2.91⨉10³ at 298 K In a reaction at equilibrium, the partial pressure of SO₂ is 137 torr and that of Cl₂ is 285 torr. What is the partial pressure of SO₂Cl₂in this mixture?
Problem 41
For the reaction A(g) ⇌ 2 B(g), a reaction vessel initially contains only A at a pressure of PA = 1.32 atm. At equilibrium, PA = 0.25 atm. Calculate the value of Kp. (Assume no changes in volume or temperature.)
Problem 42
For the reaction 2 A(g) ⇌ B(g) + 2 C(g), a reaction vessel initially contains only A at a pressure of PA = 255 mmHg. At equilibrium, PA = 55 mmHg. Calculate the value of Kp. (Assume no changes in volume or temperature.)
Problem 43
Consider the reaction: Fe3+ (aq) + SCN- (aq) ⇌ FeSCN2+ (aq). A solution is made containing an initial [Fe3+] of 1.0*10^-3 M and an initial [SCN-] of 8.0*10^-4 M. At equilibrium, [FeSCN2+] = 1.7*10^-4 M. Calculate the value of the equilibrium constant (Kc).
Problem 44
Consider the reaction: SO2Cl2(g) ⇌ SO2(g) + Cl2(g). A reaction mixture is made containing an initial [SO2Cl2] of 0.020 M. At equilibrium, [Cl2] = 1.2*10^-2 M. Calculate the value of the equilibrium constant (Kc).
Problem 45
Consider the reaction: H2(g) + I2(g) ⇌ 2 HI(g). A reaction mixture in a 3.67-L flask at a certain temperature initially contains 0.763 g H2 and 96.9 g I2. At equilibrium, the flask contains 90.4 g HI. Calculate the equilibrium constant (Kc) for the reaction at this temperature.
Problem 46
Consider the reaction: CO(g) + 2 H2(g) ⇌ CH3OH(g). A reaction mixture in a 5.19-L flask at a certain temperature contains 26.9 g CO and 2.34 g H2. At equilibrium, the flask contains 8.65 g CH3OH. Calculate the equilibrium constant (Kc) for the reaction at this temperature.
Problem 47
Consider the reaction: NH₄HS(s) ⇌ NH₃(g) + H₂S(g) At a certain temperature, K_c = 8.5⨉10^-3. A reaction mixture at this temperature containing solid NH₄HS has [NH₃] = 0.166 M and [H₂S] = 0.166 M. Will more of the solid form or will some of the existing solid decompose as equilibrium is reached?
Problem 48
Consider the reaction: 2H2S(g) ⇌ 2H2(g) + S2(g). Kp = 2.4 * 10^-4 at 1073K. A reaction mixture contains 0.112 atm of H2, 0.055 atm of S2, and 0.445 atm of H2S. Is the reaction mixture at equilibrium? If not, in what direction will the reaction proceed?
Problem 49
Silver sulfate dissolves in water according to the reaction: Ag₂SO₄(s) ⇌ 2 Ag⁺(aq) + SO₄^2-(aq) K_c = 1.1⨉10^-5 at 298 K. A 1.5-L solution contains 6.55 g of dissolved silver sulfate. If additional solid silver sulfate is added to the solution, will it dissolve?
Problem 51
Consider the reaction and the associated equilibrium constant: aA(g) ⇌ bB(g) Kc = 4.0 Find the equilibrium concentrations of A and B for each value of a and b. Assume that the initial concentration of A in each case is 1.0 M and that no B is present at the beginning of the reaction. c. a=1;b=2
Problem 52
Consider the reaction and the associated equilibrium constant: aA(g) + bB(g) ⇌ cC(g) with Kc = 5.0. Find the equilibrium concentrations of A, B, and C for the given values of a, b, and c. Assume that the initial concentrations of A and B are each 1.0 M and that no product is present at the beginning of the reaction. Calculate the equations for x without solving them for the following cases: a) a=1, b=1, c=2; b) a=1, b=1, c=1; c) a=2, b=1, c=1.
Problem 53
For the reaction shown here, K_c = 0.513 at 500 K. N₂O₄(g) ⇌ 2 NO₂(g) If a reaction vessel initially contains an N₂O₄concentration of 0.0500 M at 500 K, what are the equilibrium concentrations of N₂O₄and NO₂ at 500 K?
Problem 54
For the reaction shown here, K_c = 255 at 1000 K. CO(g) + Cl₂(g) ⇌ COCl₂(g) If a reaction mixture initially contains a CO concentration of 0.1500 M and a Cl₂ concentration of 0.175 M at 1000 K, what are the equilibrium concentrations of CO, Cl₂, and COCl₂ at 1000 K?
Problem 55
Consider the reaction: NiO(s) + CO(g) ⇌ Ni(s) + CO2(g) Kc = 4.0 * 10^3 at 1500 K. If a mixture of solid nickel(II) oxide and 0.20 M carbon monoxide comes to equilibrium at 1500 K, what is the equilibrium concentration of CO2?
Problem 56
Consider the reaction: CO(g) + H2O(g) ⇌ CO2(g) + H2(g) Kc = 102 at 500 K. If a reaction mixture initially contains 0.110 M CO and 0.110 M H2O, what will the equilibrium concentration of each of the reactants and products be?
Problem 57
Consider the reaction: HC₂H₃O₂(aq) + H₂O(l) ⇌ H₃O⁺(aq) + C₂H₃O₂^-(aq) K_c = 1.8⨉10^-5 at 25°C If a solution initially contains 0.210 M HC₂H₃O₂, what is the equilibrium concentration of H₃O⁺ at 25 °C?
Problem 58
Consider the reaction: SO₂Cl₂(g) ⇌ SO₂(g) + Cl₂(g) K_c = 2.99⨉10^-7 at 227 °C If a reaction mixture initially contains 0.175 M SO₂Cl₂, what is the equilibrium concentration of Cl₂ at 227 °C?
Problem 59
Consider the reaction: Br2(g) + Cl2(g) ⇌ 2BrCl(g) with Kp = 1.11 * 10^-4 at 150 K. A reaction mixture initially contains a Br2 partial pressure of 755 torr and a Cl2 partial pressure of 735 torr at 150 K. Calculate the equilibrium partial pressure of BrCl.
Problem 61
Consider the reaction: A(g) ⇌ B(g) + C(g) Find the equilibrium concentrations of A, B, and C for each value of K_c. Assume that the initial concentration of A in each case is 1.0 M and that the reaction mixture initially contains no products. Make any appropriate simplifying assumptions. b. K_c = 0.010