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Problem 89a
At 700 K, the equilibrium constant for the reaction CCl4(𝑔) ⇌ C(𝑠) + 2 Cl2(𝑔) is 𝐾𝑝 = 0.76. A flask is charged with 2.00 atm of CCl4, which then reaches equilibrium at 700 K. (a) What fraction of the CCl4 is converted into C and Cl2?
Problem 89b
At 700 K, the equilibrium constant for the reaction CCl4(𝑔) ⇌ C(𝑠) + 2 Cl2(𝑔) is 𝐾𝑝 = 0.76. A flask is charged with 2.00 atm of CCl4, which then reaches equilibrium at 700 K. (b) What are the partial pressures of CCl4 and Cl2 at equilibrium?
- An equilibrium mixture of H2, I2, and HI at 458 _x001F_C contains 0.112 mol H2, 0.112 mol I2, and 0.775 mol HI in a 5.00-L vessel. What are the equilibrium partial pressures when equilibrium is reestablished following the addition of 0.200 mol of HI?
Problem 91
Problem 92d,e
Consider the hypothetical reaction A(𝑔) + 2 B(𝑔) ⇌ 2 C(𝑔), for which 𝐾𝑐 = 0.25 at a certain temperature. A 1.00-L reaction vessel is loaded with 1.00 mol of compound C, which is allowed to reach equilibrium. Let the variable x represent the number of mol/L of compound A present at equilibrium.
(d) The equation from part (c) is a cubic equation (one that has the form ax3 + bx2 + cx + d = 0). In general, cubic equations cannot be solved in closed form. However, you can estimate the solution by plotting the cubic equation in the allowed range of x that you specified in part (b). The point at which the cubic equation crosses the x-axis is the solution.
(e) From the plot in part (d), estimate the equilibrium concentrations of A, B, and C. (Hint: You can check the accuracy of your answer by substituting these concentrations into the equilibrium expression.)
Problem 94
At a temperature of 700 K, the forward and reverse rate constants for the reaction 2 HI(g) ⇌ H2(g) + I2(g) are kf = 1.8×10−30 M−1s−1 and kr = 0.063 M−1s−1.
(a) What is the value of the equilibrium constant Kc at 700 K?
(b) Is the forward reaction endothermic or exothermic if the rate constants for the same reaction have values of kf = 0.097 M−1s−1 and kr = 2.6 M−1s−1 at 800 K?
- Consider the reaction IO4- (aq) + 2 H2O (l) ⇌ H4IO6- (aq); Kc = 3.5 * 10^-2. If you start with 25.0 mL of a 0.905 M solution of NaIO4 and then dilute it with water to 500.0 mL, what is the concentration of H4IO6- at equilibrium?
Problem 95
- The following equilibria were measured at 823 K: CoO(s) + H2(g) ⇄ Co(s) + H2O(g) Kc = 67; H2(g) + CO2(g) ⇄ CO(g) + H2O(g) Kc = 0.14. (c) If you were to place 5.00 g of CoO(s) in a sealed tube with a volume of 250 mL that contains CO(g) at a pressure of 1.00 atm and a temperature of 298 K, what is the concentration of the CO gas? Assume there is no reaction at this temperature and that the CO behaves as an ideal gas (you can neglect the volume of the solid).
Problem 96
Problem 96a
The following equilibria were measured at 823 K: CoO(s) + H2(g) ⇌ Co(s) + H2O(g) Kc = 67 H2(g) + CO2(g) ⇌ CO(g) + H2O(g) Kc = 0.14 (a) Use these equilibria to calculate the equilibrium constant, Kc, for the reaction CoO(s) + CO(g) ⇌ Co(s) + CO2(g) at 823 K.
Problem 96d
The following equilibria were measured at 823 K: CoO(s) + H2(g) ⇌ Co(s) + H2O(g) Kc = 67 H2(g) + CO2(g) ⇌ CO(g) + H2O(g) Kc = 0.14 (d) If the reaction vessel from part (c) is heated to 823 K and allowed to come to equilibrium, how much CoO(s) remains?
Problem 98d
The phase diagram for SO2 is shown here. (d) At which of the three points marked in red does SO2(g) most closely approach ideal-gas behavior?
Problem 98e
The phase diagram for SO2 is shown here. (e) At which of the three red points does SO2(g) behave least ideally?
- At 800 K, the equilibrium constant for the reaction A2(g) ⇌ 2 A(g) is Kc = 3.1 × 10-4. (d) If the temperature is raised to 1000 K, will the reverse rate constant kr increase or decrease? Will the change in kr be larger or smaller than the change in kf?
Problem 99
Problem 100a
In Section 11.5, we defined the vapor pressure of a liquid in terms of an equilibrium. (a) Write the equation representing the equilibrium between liquid water and water vapor and the corresponding expression for Kp.
Problem 100b
In Section 11.5, we defined the vapor pressure of a liquid in terms of an equilibrium. (b) By using data in Appendix B, give the value of Kp for this reaction at 30 C.
Problem 100c
In Section 11.5, we defined the vapor pressure of a liquid in terms of an equilibrium. (c) What is the value of Kp for any liquid in equilibrium with its vapor at the normal boiling point of the liquid?
- Is water dimer formation endothermic or exothermic, given that the Kp for water dimer formation in the gas phase is 0.050 at 300 K and 0.020 at 350 K?
Problem 101
- The protein hemoglobin (Hb) transports O2 in mammalian blood. Each Hb can bind 4 O2 molecules. The equilibrium constant for the O2 binding reaction is higher in fetal hemoglobin than in adult hemoglobin. In discussing protein oxygen-binding capacity, biochemists use a measure called the P50 value, defined as the partial pressure of oxygen at which 50% of the protein is saturated. Fetal hemoglobin has a P50 value of 19 torr, and adult hemoglobin has a P50 value of 26.8 torr. Use these data to estimate how much larger Kc is for the aqueous reaction 4 O2(aq) + Hb(aq) ⇌ Hb(O2)4(aq) in a fetus, compared to Kc for the same reaction in an adult.
Problem 102