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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]
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 7
The chart presented here shows the progress of the reaction A(π)βB(π)+C(π) to equilibrium in a closed vessel at fixed temperature. Which of the following statements about the progress of this system to equilibrium is or are true?
a. The vessel originally contained a mixture of B(g) and C(g).
b. At equilibrium, the vessel contains the same number of moles of B(g) and C(g).
c. The value of πΎπ for this reaction is > 1. [Section 15.3]
Problem 8a
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 than in vessel B.
Problem 8b
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. The solid left at the bottom of each vessel will be a mixture of PbO2(π ) and PbO(π ).
Problem 8c
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? c. The partial pressure of O2(π) will be the same in vessels A and B. [Section 15.4]
Problem 9a
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?
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)
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 20
Which of the following statements about the equilibrium 2NO2(π)β2NO(π)+O2(π) at 300 K are true and which are false?
a. The values of πΎπ and πΎπ are different.
b. If the equilibrium is reached by starting with pure NO2(π), then the equilibrium partial pressures of NO2(π) and NO(g) must be the same.
c. If the equilibrium is reached by starting with pure NO2(π), then the equilibrium partial pressures of NO(g) and O2(π) must be different.
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?
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 at 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 value of πΎπ for H2(π)ββ+ CO2(π) β CO(π) + H2O(π) 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
Problem 33a
The equilibrium 2 NO(π) + Cl2(π) β 2 NOCl(π) is established at 500.0 K. An equilibrium mixture of the three gases has partial pressures of 0.095 atm, 0.171 atm, and 0.28 atm for NO, Cl2, and NOCl, respectively. (a) Calculate πΎπ for this reaction at 500.0 K.
Problem 33b
The equilibrium 2 NO(π) + Cl2(π) β 2 NOCl(π) is established at 500.0 K. An equilibrium mixture of the three gases has partial pressures of 0.095 atm, 0.171 atm, and 0.28 atm for NO, Cl2, and NOCl, respectively. (b) If the vessel has a volume of 5.00 L, calculate Kc at this temperature.
Problem 34a
Phosphorus trichloride gas and chlorine gas react to form phosphorus pentachloride gas: PCl3(π) + Cl2(π) β PCl5(π). A 7.5-L gas vessel is charged with a mixture of PCl3(π) and Cl2(π), which is allowed to equilibrate at 450 K. At equilibrium the partial pressures of the three gases are πPCl3 = 0.124 atm, πCl2 = 0.157 atm, and πPCl5 = 1.30 atm. (a) What is the value of πΎπ at this temperature?
Problem 37d
A mixture of 0.2000 mol of CO2, 0.1000 mol of H2, and 0.1600 mol of H2O is placed in a 2.000-L vessel. The following equilibrium is established at 500 K: CO2(π) + H2(π) β CO(π) + H2O (π) (d) Calculate πΎπ for the reaction.
Problem 41a
Indicate whether each of the following statements about the reaction quotient Q is true or false: (a) The expression for ππ looks the same as the expression for πΎπ.
Problem 41b
Indicate whether each of the following statements about the reaction quotient Q is true or false: (b) If ππ < πΎπ, the reaction needs to proceed to the right to reach equilibrium.
