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Problem 14a
The equilibrium constant for the dissociation of molecular iodine, I2(g) ⇌ 2 I(g), at 800 K is Kc = 3.1 × 10–5. (a) Which species predominates at equilibrium I2 or I?
Problem 14b
The equilibrium constant for the dissociation of molecular iodine, I2(g) ⇌ 2 I(g), at 800 K is Kc = 3.1×10−5. (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 Kc for the following reactions. In each case indicate whether the reaction is homogeneous or heterogeneous.
(a) 3 NO(g) ⇌ N2O(g) + NO2(g)
(b) CH4(g) + 2 H2S(g) ⇌ CS2(g) + 4 H2(g)
(c) Ni(CO)4(g) ⇌ Ni(s) + 4 CO(g)
(d) HF(aq) ⇌ H+(aq) + F-(aq)
(e) 2Ag(s) + Zn2+(aq) ⇌ 2 Ag+(aq) + Zn(s)
(f) H2O(l) ⇌ H+(aq) + OH-(aq)
(g) 2 H2O(l) ⇌ 2 H+(aq) + 2 OH-(aq)
Problem 16a,c,d,e,f,g
Write the expressions for Kc for the following reactions. In each case indicate whether the reaction is homogeneous or heterogeneous.
(a) 2 O3(g) ⇌ 3 O2(g)
(c) 2 C2H4(g) + 2 H2O(g) ⇌ 2 C2H6(g) + O2(g)
(d) C(s) + 2 H2(g) ⇌ CH4(g)
(e) 4 HCl(aq) + O2(g) ⇌ 2 H2O(l) + 2 Cl2(g)
(f) 2 C8H18(l) + 25 O2(g) ⇌ 16 CO2(g) + 18 H2O(g)
(g) 2 C8H18(l) + 25 O2(g) ⇌ 16 CO2(g) + 18 H2O(l)
Problem 16b
Write the expressions for 𝐾𝑐 for the following reactions. In each case indicate whether the reaction is homogeneous or heterogeneous.
(b) Ti(𝑠) + 2Cl2(𝑔) ⇌ TiCl4(𝑙)
- When the following reactions come to equilibrium, does the equilibrium mixture contain mostly reactants or mostly products? (a) N2(g) + O2(g) ⇌ 2 NO(g), Kc = 1.5 × 10^-10 (b) 2 SO2(g) + O2(g) ⇌ 2 SO3(g), Kp = 2.5 × 10^9
Problem 17
Problem 18
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?
(a) 2 NO(g) + O2(g) ⇌ 2 NO2(g) Kp = 5.0 × 1012
(b) 2 HBr(g) ⇌ H2(g) + Br2(g) Kc = 5.8×10−18
Problem 19a,b
Which of the following statements are true and which are false? (a) The equilibrium constant can never be a negative number. (b) In reactions that we draw with a single-headed arrow, the equilibrium constant has a value that is very close to zero.
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 𝐾𝑐 = 0.042 for PCl3(𝑔) + Cl2(𝑔) ⇌ PCl5(𝑔) at 500 K, what is the value of 𝐾𝑝 for this reaction at this temperature?
- Calculate Kc at 303 K for SO2(g) + Cl2(g) ⇌ SO2Cl2(g) if Kp = 34.5 at this temperature.
Problem 22
- The equilibrium constant for the reaction 2 NO(g) + Br2(g) ⇌ 2 NOBr(g) is Kc = 1.3 * 10^-2 at 1000 K. (b) Calculate Kc for 2 NOBr(g) ⇌ 2 NO(g) + Br2(g). (c) Calculate Kc for NOBr(g) ⇌ NO(g) + 1/2 Br2(g).
Problem 23
Problem 24b
Consider the following equilibrium: 2 H2(g) + S2(g) ⇌ 2 H2S(g) Kc = 1.08 × 107 at 700°C (b) Does the equilibrium mixture contain mostly H2 and S2 or mostly H2S?
Problem 24c
Consider the following equilibrium: 2 H2(g) + S2(g) ⇌ 2 H2S(g) Kc = 1.08 × 107 at 700°C (c) Calculate the value of 𝐾𝑐 if you rewrote the equation H2(g) + 1/2 S2(g) ⇌ H2S(g)
Problem 25a,b
At 1000 K, 𝐾𝑝 = 1.85 for the reaction SO2(𝑔) + 1/2 O2(𝑔) ⇌ SO3(𝑔) (a) What is the value of Kp for the reaction SO3(𝑔) ⇌ SO2(𝑔) + 1/2 O2(𝑔)? (b) What is the value of Kp for the reaction 2 SO2(𝑔) + O2(𝑔) ⇌ 2 SO3(𝑔)?
Problem 25c
At 1000 K, 𝐾𝑝 = 1.85 for the reaction SO2(𝑔) + 12 O2(𝑔) ⇌ SO3(𝑔) (c) What is the value of 𝐾𝑐 for the reaction in part (b)?
Problem 26a
Consider the following equilibrium, for which at 𝐾𝑝 = 0.0752 at 480°C: 2 Cl2(𝑔) + 2 H2O(𝑔) ⇌ 4 HCl(𝑔) + O2(𝑔) (a) What is the value of 𝐾𝑝 for the reaction 4 HCl(𝑔) + O2(𝑔) ⇌ 2 Cl2(𝑔) + 2 H2O(𝑔)?
Problem 27
The following equilibria were attained at 823 K:
CoO(s) + H2(g) → Co(s) + H2O(g) Kc = 67
CoO(s) + CO(g) → Co(s) + CO2(g) Kc = 490
Based on these equilibria, calculate the value of 𝐾𝑐 for H2(𝑔) + CO2(𝑔) ⇌ CO(𝑔) + H2O(𝑔) at 823 K.
Problem 28
Consider the equilibrium N2(𝑔) + O2(𝑔) + Br2(𝑔) ⇌ 2 NOBr(𝑔) Calculate the equilibrium constant 𝐾𝑝 for this reaction, given the following information at 298 K:
2 NO(𝑔) + Br2(𝑔) ⇌ 2 NOBr(𝑔) 𝐾𝑐 = 2.02
NO(𝑔) ⇌ N2(𝑔) + O2(𝑔) 𝐾𝑐 = 2.1×1030
- Mercury(I) oxide decomposes into elemental mercury and elemental oxygen: 2 Hg2O(s) ⇌ 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) ⇌ 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 °C, where it partially decomposes to hydrogen and iodine: 2 HI(g) ⇌ H2(g) + I2(g). At equilibrium, it is found that [HI] = 3.53 × 10⁻³ M, [H2] = 4.79 × 10⁻⁴ M, and [I2] = 4.79 × 10⁻⁴ M. What is the value of Kc at this temperature?
Problem 32
Problem 33a
The equilibrium 2 NO(𝑔) + Cl2(𝑔) ⇌ 2 NOCl(𝑔) 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 𝐾𝑝 for this reaction at 500.0 K.
Problem 33b
The equilibrium 2 NO(𝑔) + Cl2(𝑔) ⇌ 2 NOCl(𝑔) 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(𝑔) + Cl2(𝑔) ⇌ PCl5(𝑔). A 7.5-L gas vessel is charged with a mixture of PCl3(𝑔) and Cl2(𝑔), which is allowed to equilibrate at 450 K. At equilibrium the partial pressures of the three gases are 𝑃PCl3 = 0.124 atm, 𝑃Cl2 = 0.157 atm, and 𝑃PCl5 = 1.30 atm. (a) What is the value of 𝐾𝑝 at this temperature?
- A mixture of 0.10 mol of NO, 0.050 mol of H2, and 0.10 mol of H2O is placed in a 1.0-L vessel at 300 K. The following equilibrium is established: 2 NO(g) + 2 H2(g) ⇌ N2(g) + 2 H2O(g). At equilibrium [NO] = 0.062 M. (a) Calculate the equilibrium concentrations of H2, N2, and H2O.
Problem 35
- A mixture of 1.374 g of H2 and 70.31 g of Br2 is heated in a 2.00-L vessel at 700 K. These substances react according to H2(g) + Br2(g) ⇌ 2 HBr(g). At equilibrium, the vessel is found to contain 0.566 g of H2. (a) Calculate the equilibrium concentrations of H2, Br2, and HBr.
Problem 36
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(g) + H2(g) ⇌ CO(g) + H2O(g) (d) Calculate Kc for the reaction.
- A flask is charged with 1.500 atm of N2O4 and 1.00 atm NO2 at 25 _x001F_C, and the following equilibrium is achieved: N2O4(g) ⇌ 2 NO2(g). After equilibrium is reached, the partial pressure of NO2 is 0.512 atm. (b) Calculate the value of Kp for the reaction. (c) Calculate Kc for the reaction.
Problem 38
- Two different proteins X and Y are dissolved in aqueous solution at 37 _x001F_C. The proteins bind in a 1:1 ratio to form XY. A solution that is initially 1.00 mM in each protein is allowed to reach equilibrium. At equilibrium, 0.20 mM of free X and 0.20 mM of free Y remain. What is Kc for the reaction?
Problem 39