Problem 21a
Write an expression for the equilibrium constant of each chemical equation.
a. SbCl5(g) ⇌ SbCl3(g) + Cl2(g)
b.2 BrNO(g) ⇌ 2 NO(g) + Br2(g)
c. CH4(g) + 2 H2S(g) ⇌ CS2(g) + 4 H2(g)
d. 2 CO(g) + O2(g) ⇌ 2 CO2(g)
Problem 22a
Find and fix each mistake in the equilibrium constant expressions. a. 2 H2S(g) ⇌ 2 H2(g) + S2(g) K = [H2][S2]/[H2S]
Problem 22b
Find and fix each mistake in the equilibrium constant expressions. b. CO(g) + Cl2(g) ⇌ COCl2(g) K = [CO][Cl2]/[COCl2]
Problem 23
When this reaction comes to equilibrium, will the concentrations of the reactants or products be greater? Does the answer to this question depend on the initial concentrations of the reactants and products? A(g)+B(g) ⇌ 2 C(g) Kc = 1.4⨉10-5
Problem 24
Ethene (C2H4) can be halogenated by this reaction: C2H4(g) + X2(g) ⇌ C2H4X2(g) where X2 can be Cl2 (green), Br2 (brown), or I2 (purple). Examine the three figures representing equilibrium concentrations in this reaction at the same temperature for the three different hal- ogens. Rank the equilibrium constants for the three reactions from largest to smallest.
Problem 25a
H2 and I2 are combined in a flask and allowed to react according to the reaction: H2(g) + I2(g) ⇌ 2 HI(g) Examine the figures (sequential in time) and answer the questions: a. Which figure represents the point at which equilibrium is reached?
Problem 26
A chemist trying to synthesize a particular compound attempts two different synthesis reactions. The equilibrium constants for the two reactions are 23.3 and 2.2⨉104 at room temperature. However, upon carrying out both reactions for 15 minutes, the chemist finds that the reaction with the smaller equilibrium constant produces more of the desired product. Explain how this might be possible.
Problem 29a
This reaction has an equilibrium constant of Kp = 2.26⨉104 at 298 K. CO(g) + 2 H2(g) ⇌ CH3OH(g) Calculate Kp for each reaction and predict whether reactants or products will be favored at equilibrium. a. CH3OH(g) ⇌ CO(g) + 2 H2(g)
Problem 29b
This reaction has an equilibrium constant of Kp = 2.26⨉104 at 298 K. CO(g) + 2 H2(g) ⇌ CH3OH(g) Calculate Kp for each reaction and predict whether reactants or products will be favored at equilibrium.
b. 1/2 CO(g) + H2 (g) ⇌ 1/2 CH3OH(g)
Problem 29c
This reaction has an equilibrium constant of Kp = 2.26⨉104 at 298 K. CO(g) + 2 H2(g) ⇌ CH3OH(g) Calculate Kp for each reaction and predict whether reactants or products will be favored at equilibrium.
c. 2 CH3OH(g) ⇌ 2 CO(g) + 4 H2(g)
Problem 30a
This reaction has an equilibrium constant of Kp = 2.2⨉106 at 298 K. 2 COF2(g) ⇌ CO2(g) + CF4(g) Calculate Kp for each reaction and predict whether reactants or products will be favored at equilibrium.
a. COF2 (g) ⇌ 1/2 CO2(g) + 1/2 CF4(g)
Problem 30b
This reaction has an equilibrium constant of Kp = 2.2⨉106 at 298 K. 2 COF2(g) ⇌ CO2(g) + CF4(g) Calculate Kp for each reaction and predict whether reactants or products will be favored at equilibrium.
b. 6 COF2(g) ⇌ 3 CO2(g) + 3 CF4(g)
Problem 30c
This reaction has an equilibrium constant of Kp = 2.2⨉106 at 298 K. 2 COF2(g) ⇌ CO2(g) + CF4(g) Calculate Kp for each reaction and predict whether reactants or products will be favored at equilibrium.
c. 2 CO2(g) + 2 CF4(g) ⇌ 4 COF2(g)
Problem 31
Consider the reactions and their respective equilibrium
constants:
NO(g) + 1/2 Br (g) ⇌ NOBr(g) Kp = 5.3
2 NO(g) ⇌ N2(g) + O2(g) Kp = 2.1⨉1030
Use these reactions and their equilibrium constants to predict
the equilibrium constant for the following reaction: N2(g) + O2(g) + Br2(g) ⇌ 2 NOBr(g)
Problem 33a
Calculate Kc for each reaction. a. N2(g) + 3 H2(g) ⇌ 2 NH3(g) Kp = 6.2×10^5 (at 298 K)
Problem 33b
Calculate Kc for each reaction. b. N2(g) + O2(g) ⇌ 2 NO(g) Kp = 4.10×10^–31 (at 298 K)
Problem 34a
Calculate Kp for each reaction. a. I2(g) + Cl2(g) ⇌ 2 ICl(g) Kc = 81.9 (at 298 K)
Problem 34b
Calculate Kp for each reaction. b. CH4(g) + H2O(g) ⇌ CO(g) + 3 H2(g) Kc = 1.3×10^22 (at 298 K)
- Write an equilibrium expression for each chemical equation involving one or more solid or liquid reactants or products: a. CO32-(aq) + H2O(l) ⇌ HCO3-(aq) + OH-(aq) b. 2 KClO3(s) ⇌ 2 KCl(s) + 3 O2(g) c. HF(aq) + H2O(l) ⇌ H3O+(aq) + F-(aq) d. NH3(aq) + H2O(l) ⇌ NH4+(aq) + OH-(aq)
Problem 35
- Find and fix the mistake in the equilibrium expression. PCl5(g) ⇌ PCl3(l) + Cl2(g) Kc = [Cl2]/[PCl5]
Problem 36
Problem 39
Consider the reaction: N2(g) + 3 H2(g) ⇌ 2 NH3(g) Complete the table. Assume that all concentrations are equilibrium concentrations in M.
T (K) [N2] [H2] [NH3] Kc
500 0.115 0.105 0.439 _
575 0.110 _ 0.128 9.6
775 0.120 0.140 _ 0.0584
Problem 40
Consider the following reaction: H2(g) + I2(g) ⇌ 2 HI(g) Complete the table. Assume that all concentrations are equilibrium concentrations in M.
T (°C) [H2] [I2] [HI] Kc
25 0.0355 0.0388 0.922 _
340 _ 0.0455 0.387 9.6
445 0.0485 0.0468 _ 50.2
Problem 41
Consider the reaction:
2 NO( g) + Br2( g)Δ2 NOBr( g) Kp = 28.4 at 298 K
In a reaction mixture at equilibrium, the partial pressure of NO is 125 torr and that of Br2 is 148 torr. What is the partial pressure of NOBr in this mixture?
Problem 42
Consider the reaction: SO2Cl2(g) ⇌ SO2(g) + Cl2(g) Kp = 2.91*10^3 at 298 K In a reaction at equilibrium, the partial pressure of SO2 is 117 torr and that of Cl2 is 205 torr. What is the partial pressure of SO2Cl2 in this mixture?
- Consider the reaction: Fe3+ (aq) + SCN- (aq) ⇌ FeSCN2+ (aq). A solution is made containing an initial [Fe3+] of 1.0*10^-3 M and an initial [SCN-] of 8.0*10^-4 M. At equilibrium, [FeSCN2+] = 1.7*10^-4 M. Calculate the value of the equilibrium constant (Kc).
Problem 45
- Consider the reaction: SO2Cl2(g) ⇌ SO2(g) + Cl2(g). A reaction mixture is made containing an initial [SO2Cl2] of 0.020 M. At equilibrium, [Cl2] = 1.2*10^-2 M. Calculate the value of the equilibrium constant (Kc).
Problem 46
- Consider the reaction: H2(g) + I2(g) ⇌ 2 HI(g). A reaction mixture in a 3.67-L flask at a certain temperature initially contains 0.763 g H2 and 96.9 g I2. At equilibrium, the flask contains 90.4 g HI. Calculate the equilibrium constant (Kc) for the reaction at this temperature.
Problem 47
- 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 48
Problem 49
Consider the reaction:
NH4HS(s)ΔNH3( g) + H2S( g)
At a certain temperature, Kc = 8.5 * 10 - 3. A reaction mixture at this temperature containing solid NH4HS has [NH3] = 0.0822 M and [H2S] = 0.0822M. Will more of the solid form, or will some of the existing solid decompose as equilibrium is reached?
Problem 51
Silver sulfate dissolves in water according to the reaction: Ag2SO4(s) ⇌ 2Ag+(aq) + SO42-(aq) Kc = 1.1 * 10-5 at 298K A 1.5-L solution contains 5.14 g of dissolved silver sulfate. If additional solid silver sulfate is added to the solution, will it dissolve?
Ch.16 - Chemical Equilibrium