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Problem 1a
(a) Based on the following energy profile, predict whether kf > kr or kf < kr. [Section 15.1]
Problem 2
The following diagrams represent a hypothetical reaction A Β‘ B, with A represented by red spheres and B represented by blue spheres. The sequence from left to right represents the system as time passes. Does the system reach equilibrium? If so, in which diagram(s) is the system in equilibrium? [Sections 15.1 and 15.2]
- Consider the equilibrium Na2O(s) + SO2(g) β Na2SO3(s). (a) Write the equilibrium-constant expression for this reaction in terms of partial pressures. (b) All the compounds in this reaction are soluble in water. Rewrite the equilibrium-constant expression in terms of molarities for the aqueous reaction.
Problem 3
Problem 4d
The following diagram represents a reaction shown going to completion. Each molecule in the diagram represents 0.1 mol, and the volume of the box is 1.0 L. (d) Assuming that all of the molecules are in the gas phase, calculate n, the change in the number of gas molecules that accompanies the reaction. [Section 15.2]
Problem 6
Ethene (C2H4) reacts with halogens (X2) by the following reaction:
C2H4(π) + X2(π) β C2H4X2(π)
The following figures represent the concentrations at equilibrium at the same temperature when X2 is Cl2 (green), Br2 (brown), and I2 (purple). List the equilibria from smallest to largest equilibrium constant. [Section 15.3]
Problem 7a
When lead(IV) oxide is heated above 300Β°C, it decomposes according to the reaction, 2 PbO2(π ) β 2PbO(π ) + O2(π). Consider the two sealed vessels of PbO2 shown here. If both vessels are heated to 400Β°C and allowed to come to equilibrium, which of the following statements is or are true? a. There will be less PbO2 remaining in vessel A,
Problem 7b
When lead(IV) oxide is heated above 300Β°C, it decomposes according to the reaction, 2 PbO2(π )β2PbO(π )+O2(π). Consider the two sealed vessels of PbO2 shown here. If both vessels are heated to 400Β°C and allowed to come to equilibrium, which of the following statements is or are true?
b. There will be less PbO2 remaining in vessel B,
Problem 7c
When lead(IV) oxide is heated above 300Β°C, it decomposes according to the reaction, 2 PbO2(π ) β 2PbO(π ) + O2(π). Consider the two sealed vessels of PbO2 shown here. If both vessels are heated to 400Β°C and allowed to come to equilibrium, which of the following statements is or are true? (c) The amount of PbO2 remaining in each vessel will be the same. [Find more in Section 15.4]
Problem 8a
The reaction A2 + B2 β 2 AB has an equilibrium constant Kc = 1.5. The following diagrams represent reaction mixtures containing A2 molecules (red), B2 molecules (blue), and AB molecules. (a) Which reaction mixture is at equilibrium?
- The reaction PClβ(g) + Clβ(g) β PClβ (g) has Kp = 0.0870 at 300 _x001F_C. A flask is charged with 0.50 atm PClβ, 0.50 atm Clβ, and 0.20 atm PClβ at this temperature. (d) The reaction is exothermic. What effect will increasing the temperature of the system have on the mole fraction of Clβ in the equilibrium mixture?
Problem 9
Problem 10a
The diagram shown here represents the equilibrium state for the reaction A2(π) + 2B(π) β 2AB(π). (a) Assuming the volume is 2 L, calculate the equilibrium constant πΎπ for the reaction.
Problem 13b
Suppose that the gas-phase reactions A β B and B β A are both elementary reactions with rate constants of 4.7Γ10β3β sβ1 and 5.8Γ10β1 sβ1, respectively. (b) Which is greater at equilibrium, the partial pressure of A or the partial pressure of B?
Problem 14b
The equilibrium constant for the dissociation of molecular iodine, I2(π) β 2 I(π), at 800 K is πΎπ = 3.1Γ10β5. (b) Assuming both forward and reverse reactions are elementary reactions, which reaction has the larger rate constant, the forward or the reverse reaction?
Problem 15e
Write the expression for πΎπ for the following reactions. In each case indicate whether the reaction is homogeneous or heterogeneous.
(e) 2Ag(π ) + Zn2+(ππ) β 2 Ag+(ππ) + Zn(π )
Problem 16b
Write the expressions for πΎπ for the following reactions. In each case indicate whether the reaction is homogeneous or heterogeneous.
(b) Ti(π ) + 2Cl2(π) β TiCl4(π)
Problem 16g
Write the expressions for πΎπ for the following reactions. In each case indicate whether the reaction is homogeneous or heterogeneous. (g) 2 C8H18(π) + 25 O2(π) β 16 CO2(π) + 18 H2O(π)
- When the following reactions come to equilibrium, does the equilibrium mixture contain mostly reactants or mostly products? (a) N2(g) + O2(g) β 2 NO(g), Kc = 1.5 Γ 10^-10 (b) 2 SO2(g) + O2(g) β 2 SO3(g), Kp = 2.5 Γ 10^9
Problem 17
Problem 18b
Which of the following reactions lies to the right, favoring the formation of products, and which lies to the left, favoring the formation of reactants? (b) 2 HBr(π) β H2(π) + Br2(π) πΎπ = 5.8Γ10β18
Problem 19c
Which of the following statements are true and which are false? (c) As the value of the equilibrium constant increases, the speed at which a reaction reaches equilibrium must increase.
Problem 21
If πΎπ = 0.042 for PCl3(π) + Cl2(π) β PCl5(π) at 500 K, what is the value of πΎπ for this reaction at this temperature?
- Calculate Kc at 303 K for SO2(g) + Cl2(g) β SO2Cl2(g) if Kp = 34.5 at this temperature.
Problem 22
- The equilibrium constant for the reaction 2 NO(g) + Br2(g) β 2 NOBr(g) is Kc = 1.3 * 10^-2 at 1000 K. (b) Calculate Kc for 2 NOBr(g) β 2 NO(g) + Br2(g). (c) Calculate Kc for NOBr(g) β NO(g) + 1/2 Br2(g).
Problem 23
Problem 24c
Consider the following equilibrium: 2 H2(π) + S2(βπ) β 2 H2S(π) πΎπ = 1.08Γ107 at 700Β°C (c) Calculate the value of πΎπ if you rewrote the equation H2(π) + 1/2 S2(βπ) β H2S(π)
Problem 25c
At 1000 K, πΎπ = 1.85 for the reaction SO2(π) + 12 O2(π) β SO3(π) (c) What is the value of πΎπ for the reaction in part (b)?
Problem 26a
Consider the following equilibrium, for which πΎπ = 0.0752 at 480Β°C: 2 Cl2(π) + 2 H2O(π) β 4 HCl(π) + O2(π) (a) What is the value of πΎπ for the reaction 4 HCl(π) + O2(π) β 2 Cl2(π) + 2 H2O(π)?
Problem 27
The following equilibria were attained at 823 K:
CoO(s) + H2(g) β Co(s) + H2O(g) Kc = 67
CoO(s) + CO(g) β Co(s) + CO2(g) Kc = 490
Based on these equilibria, calculate the equilibrium constant for H2(g) + CO2(g) β CO(g) + H2O(g) at 823 K.
Problem 28
Consider the equilibrium N2(π) + O2(π) + Br2(π) β 2 NOBr(π) Calculate the equilibrium constant πΎπ for this reaction, given the following information at 298 K:
2 NO(π) + Br2(π) β 2 NOBr(π) πΎπ = 2.02
NO(π) β N2(π) + O2(π) πΎπ = 2.1Γ1030
- Mercury(I) oxide decomposes into elemental mercury and elemental oxygen: 2 Hg2O(s) β 4 Hg(l) + O2(g). (a) Write the equilibrium-constant expression for this reaction in terms of partial pressures. (b) Suppose you run this reaction in a solvent that dissolves elemental mercury and elemental oxygen. Rewrite the equilibrium-constant expression in terms of molarities for the reaction, using (solv) to indicate solvation.
Problem 29
- Methanol (CH3OH) is produced commercially by the catalyzed reaction of carbon monoxide and hydrogen: CO(g) + 2 H2(g) β CH3OH(g). An equilibrium mixture in a 2.00-L vessel is found to contain 0.0406 mol CH3OH, 0.170 mol CO, and 0.302 mol H2 at 500 K. Calculate Kc at this temperature.
Problem 31
- Gaseous hydrogen iodide is placed in a closed container at 425 Β°C, where it partially decomposes to hydrogen and iodine: 2 HI(g) β H2(g) + I2(g). At equilibrium, it is found that [HI] = 3.53 Γ 10β»Β³ M, [H2] = 4.79 Γ 10β»β΄ M, and [I2] = 4.79 Γ 10β»β΄ M. What is the value of Kc at this temperature?
Problem 32
