Ch.15 - Chemical Equilibrium

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Tro 4th Edition

Ch.15 - Chemical Equilibrium

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 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

Problem 62

Consider the reaction: A(g) ⇌ 2B(g). Find the equilibrium partial pressures of A and B for each value of Kp. Assume that the initial partial pressure of B in each case is 1.0 atm and that the initial partial pressure of A is 0.0 atm. Make any appropriate simplifying assumptions. a. Kp = 1.0 b. Kp = 1.0 × 10^-4 c. Kp = 1.0 × 10^5.

Problem 63

Consider this reaction at equilibrium: CO(g) + Cl2(g) ⇌ COCl2(g) Predict whether the reaction will shift left, shift right, or remain unchanged after each disturbance. a. COCl2 is added to the reaction mixture. b. Cl2 is added to the reaction mixture. c. COCl2 is removed from the reaction mixture.

Problem 64a

Consider this reaction at equilibrium: 2 BrNO(g) ⇌ 2 NO(g) + Br₂(g) Predict whether the reaction will shift left, shift right, or remain unchanged after each disturbance. a. NO is added to the reaction mixture.

Problem 64b

Consider this reaction at equilibrium: 2 BrNO(g) ⇌ 2 NO(g) + Br₂(g) Predict whether the reaction will shift left, shift right, or remain unchanged after each disturbance. b. BrNO is added to the reaction mixture.

Problem 64c

Consider this reaction at equilibrium: 2 BrNO(g) ⇌ 2 NO(g) + Br₂(g) Predict whether the reaction will shift left, shift right, or remain unchanged after each disturbance. c. Br₂is removed from the reaction mixture.

Problem 65

Consider this reaction at equilibrium: 2KClO3(s) ⇌ 2KCl(s) + 3O2(g). Predict whether the reaction will shift left, shift right, or remain unchanged after each disturbance. a. O2 is removed from the reaction mixture. b. KCl is added to the reaction mixture. c. KClO3 is added to the reaction mixture. d. O2 is added to the reaction mixture.

Problem 66

Consider this reaction at equilibrium: C(s) + H₂O(g) ⇌ CO(g) + H₂(g) Predict whether the reaction will shift left, shift right, or remain unchanged after each disturbance. a. C is added to the reaction mixture. b. H₂O is condensed and removed from the reaction mixture. Predict whether the reaction will shift left, shift right, or remain unchanged after each disturbance. c. CO is added to the reaction mixture. d. H₂ is removed from the reaction mixture.

Problem 67

Each reaction is allowed to come to equilibrium, and then the volume is changed as indicated. Predict the effect (shift right, shift left, or no effect) of the indicated volume change. a. I₂( g) ⇌ 2 I( g) (volume is increased) b. 2 H₂S( g) ⇌ 2 H₂( g) + S₂(g) (volume is decreased) c. I₂(g) + Cl₂(g) ⇌ 2 ICl(g) (volume is decreased)

Problem 68a

Each reaction is allowed to come to equilibrium, and then the volume is changed as indicated. Predict the effect (shift right, shift left, or no effect) of the indicated volume change. a. CO(g) + H₂O( g) ⇌ CO₂(g) + H₂(g) (volume is decreased)

Problem 68b

Problem 69

This reaction is endothermic. C(s) + CO₂(g) ⇌ 2 CO(g) Predict the effect (shift right, shift left, or no effect) of increasing and decreasing the reaction temperature. How does the value of the equilibrium constant depend on temperature?

Problem 71a,b,d,f

Coal, which is primarily carbon, can be converted to natural gas, primarily CH₄, by the exothermic reaction: C(s) + 2 H₂(g) ⇌ CH₄(g) Which disturbance will favor CH₄ at equilibrium?

a. adding more C to the reaction mixture b. adding more H₂ to the reaction mixture d. lowering the volume of the reaction mixture f. adding neon gas to the reaction mixture

Problem 71c

Coal, which is primarily carbon, can be converted to natural gas, primarily CH₄, by the exothermic reaction: C(s) + 2 H₂(g) ⇌ CH₄(g) Which disturbance will favor CH₄ at equilibrium? c. raising the temperature of the reaction mixture

Problem 73

Carbon monoxide replaces oxygen in oxygenated hemoglobin according to the reaction: HbO₂(aq) + CO(aq) ⇌ HbCO(aq) + O₂(aq) a. Use the reactions and associated equilibrium constants at body temperature given here to find the equilibrium constant for the reaction just shown. Hb(aq) + O₂(aq) ⇌ HbO₂(aq) K_c = 1.8 Hb(aq) + CO(aq) ⇌ HbCO(aq) K_c = 306

Problem 75

The reaction CO2(g) + C(s) ⇌ 2 CO(g) has Kp = 5.78 at 1200 K. a. Calculate the total pressure at equilibrium when 4.45 g of CO2 is introduced into a 10.0-L container and heated to 1200 K in the presence of 2.00 g of graphite. b. Repeat the calculation of part a in the presence of 0.50 g of graphite.

Problem 77

At 650 K, the reaction MgCO₃(s) ⇌ MgO(s) + CO₂(g) has K_p = 0.026. A 10.0-L container at 650 K has 1.0 g of MgO(s) and CO₂ at P = 0.0260 atm. The container is then compressed to a volume of 0.100 L. Find the mass of MgCO₃ that is formed.

Problem 78

A system at equilibrium contains I2(g) at a pressure of 0.21 atm and I(g) at a pressure of 0.23 atm. The system is then compressed to half its volume. Find the pressure of each gas when the system returns to equilibrium.