Phosphorus pentachloride, PCl5, decomposes on heating to give phosphorus trichloride, PCl5, and chlorine.
A closed 2.90-L vessel initially contains 0.0564 mol PCl5. What is the total pressure at 250°C when equilibrium is achieved? The value of Kc at 250°C is 4.15 × 10−2.
Interpretation:
The total pressure of the system at equilibrium has to be found.
Concept introduction:
Equilibrium constant
Consider the reaction where the reactant A is giving product B.
On rearranging,
Where,
Ideal gas equation is an equation that is describing the state of a imaginary ideal gas.
Where,
P is the pressure of the gas
V is the volume
n is the number of moles of gas
R is the universal gas constant
T is the temperature
Answer to Problem 14.137QP
The total pressure of the system at equilibrium is found to be
Explanation of Solution
Given,
The initial amount of
The volume of the vessel
The equilibrium constant
To find initial concentration of reactant
The initial concentrations of the
To find the equilibrium composition.
Using the table approach, the equilibrium concentrations of the reactants and the products can be found.
The equilibrium concentration values are then substituted into the equilibrium expression to get the change in concentration x.
On rearranging we get a quadratic equation.
On solving the quadratic equation the value of x obtained.
On solving we get two values for x, the logical value for x is taken.
Total concentration of the reaction mixture at equilibrium is the sum of the concentration of products and reactants.
To find the total pressure
At constant temperature,
Where
The total concentration is substituted in the ideal gas equation to get the total pressure.
The equilibrium composition of the given reaction mixture was found. The total concentration of the equilibrium mixture is then substituted in the ideal gas equation to get the value of total pressure.
Want to see more full solutions like this?
Chapter 14 Solutions
General Chemistry (Instructor's)
- Kc = 5.6 1012 at 500 K for the dissociation of iodine molecules to iodine atoms. I2(g) 2 I(g) A mixture has [I2] = 0.020 mol/Land [I] = 2.0 108 mol/L. Is the reaction at equilibrium (at 500 K)? If not, which way must the reaction proceed to reach equilibrium?arrow_forwardA mixture of SO2, O2, and SO3 at 1000 K contains the gases at the following concentrations: [SO2] = 5.0 103 mol/L, [O2] = 1.9 103 mol/L, and [SO3] = 6.9 103 mol/L. Is the reaction at equilibrium? If not, which way will the reaction proceed to reach equilibrium? 2 SO2(g) + O2(g) 2 SO3(g) Kc = 279arrow_forwardNitrosyl chloride, NOC1, decomposes to NO and Cl2 at high temperatures. 2 NOCl(g) ⇌ 2 NO(g) + Cl2(g) Suppose you place 2.00 mol NOC1 in a 1.00–L flask, seal it, and raise the temperature to 462 °C. When equilibrium has been established, 0.66 mol NO is present. Calculate the equilibrium constant Kc for the decomposition reaction from these data.arrow_forward
- Lexan is a plastic used to make compact discs, eyeglass lenses, and bullet-proof glass. One of the compounds used to make Lexan is phosgene (COCl2), an extremely poisonous gas. Phosgene decomposes by the reaction COCl2(g)CO(g)+Cl2(g) for which Kp 6.8 109 at 100C. If pure phosgene at an initial pressure of 1.0 atm decomposes, calculate the equilibrium pressures of all species.arrow_forwardCalcium carbonate, CaCO3, decomposes when heated to give calcium oxide. CaO, and carbon dioxide, CO2. CaCO3(s)CaO(s)+CO2(g) Kp for this reaction at 900C is 1.040 What would be the yield of carbon dioxide (in grams) when 1.000 g of CaCO3 and 1.000 g CaO are heated to 900C in a 1.000-L vessel. (Ignore the volume occupied by the solids.) What would be the effect of adding a similar quantity of carbon dioxide to this equilibrium mixture? What would happen if the quantity of calcium carbonate were doubled?arrow_forwardA mixture of 0.0565 mol phosphorus pentachloride, PCl5, and 0.0800 mol helium gas, He, was placed in a 1.000-L flask and heated to 250.0C. The phosphorus pentachloride decomposes at this temperature to give phosphorus trichloride, PCl3, and chlorine gas, Cl2. The helium gas is inert. PCl5(g)PCl3(g)+Cl2(g) What is the partial pressure of helium in this equilibrium mixture at 250.0C? At equilibrium, the total pressure is found to be 6.505 atm. What is Kc for the dissociation of PCl5?arrow_forward
- In a 3.0-L vessel, the following equilibrium partial pressures are measured: N2, 190 torr; H2, 317 torr; NH3, 1.00103 torr. N2(g)+3H2(g)2NH3(g) (a) How will the partial pressures of H2, N2, and NH3 change if H2 is removed from the system? Will they increase, decrease, or remain the same? (b) Hydrogen is removed from the vessel until the partial pressure of nitrogen, at equilibrium, is 250 torr. Calculate the partial pressures of the other substances under the new conditions.arrow_forwardCarbon dioxide reacts with carbon to give carbon monoxide according to the equation C(s)+CO2(g)2CO(g) At 700. C, a 2.0-L sealed flask at equilibrium contains 0.10 mol CO, 0.20 mol CO2, and 0.40 mol C. Calculate the equilibrium constant KP for this reaction at the specified temperature.arrow_forwardGaseous acetic acid molecules have a certain tendency to form dimers. (A dimer is a molecules formed by the association of two identical, simpler molecules.) The equilibrium constant Kp at 25C for this reaction is 1.3 103. a If the initial pressure of CH3COOH monomer (the simpler molecule) is 7.5 103 atm, what are the pressures of monomer and dimer when the system comes to equilibrium? (The simpler quadratic equation is obtained by assuming that all of the acid molecules have dimerized and then some of it dissociates to monomer.) b Why do acetic acid molecules dimerize? What type of structure would you draw for the dimer? c As the temperature decreases, would you expect the percentage of dimer to increase or decrease? Why?arrow_forward
- For the reaction N2(g)+3H2(g)2NH3(g) show that Kc = Kp(RT)2 Do not use the formula Kp = Kc(RT)5n given in the text. Start from the fact that Pi = [i]RT, where Pi is the partial pressure of substance i and [i] is its molar concentration. Substitute into Kc.arrow_forwardKc for the decomposition of ammonium hydrogen sulfide is 1.8 104 at 25 C. NH4HS(s) NH3(g) + H2S(g) (a) When the pure salt decomposes in a flask, what are the equilibrium concentrations of NH3 and H2S? (b) If NH4HS is placed in a flask already containing 0.020 mol/L of NH3 and then the system is allowed to come to equilibrium, what are the equilibrium concentrations of NH3 and H2S?arrow_forwardAt high temperatures, a dynamic equilibrium exists between carbon monoxide, carbon dioxide, and solid carbon. C(s)+CO2(g)2CO(g);H=172.5kJ At 850C, Kc is 0.153. a What is the value of Kp? b If the original reaction system consisted of just carbon and 1.50 atm of CO2, what are the pressures of CO2 and CO when equilibrium has been established? c How will the equilibrium pressure of CO change if the temperature is decreased?arrow_forward
- General Chemistry - Standalone book (MindTap Cour...ChemistryISBN:9781305580343Author:Steven D. Gammon, Ebbing, Darrell Ebbing, Steven D., Darrell; Gammon, Darrell Ebbing; Steven D. Gammon, Darrell D.; Gammon, Ebbing; Steven D. Gammon; DarrellPublisher:Cengage LearningChemistry: Principles and ReactionsChemistryISBN:9781305079373Author:William L. Masterton, Cecile N. HurleyPublisher:Cengage LearningChemistry: The Molecular ScienceChemistryISBN:9781285199047Author:John W. Moore, Conrad L. StanitskiPublisher:Cengage Learning
- Chemistry & Chemical ReactivityChemistryISBN:9781337399074Author:John C. Kotz, Paul M. Treichel, John Townsend, David TreichelPublisher:Cengage LearningChemistry & Chemical ReactivityChemistryISBN:9781133949640Author:John C. Kotz, Paul M. Treichel, John Townsend, David TreichelPublisher:Cengage Learning