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Phase Equilibrium: Two Components in Piston-Cylinders

Phase Equilibrium: Two Components in Piston-Cylinders. Contributions by: John L. Falconer & Will Medlin Department of Chemical and Biological Engineering University of Colorado Boulder, CO 80309-0424 Supported by the National Science Foundation.

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Phase Equilibrium: Two Components in Piston-Cylinders

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  1. Phase Equilibrium:Two Componentsin Piston-Cylinders Contributions by: John L. Falconer & Will MedlinDepartment of Chemical and Biological EngineeringUniversity of ColoradoBoulder, CO 80309-0424 Supported by the National Science Foundation

  2. A 2-componet system is at 98oC and 90 kPa. How many different equilibrium phase conditions are possible for this system (for example: liquid, vapor, liquid and vapor)? 1 2 3 1 or 2 1 or 3

  3. A piston-cylinder system contains components A and B in vapor-liquid equilibrium. Assume ideal solution and ideal gas, with xA = 0.25, yA = 0.50. A small weight was added to the piston, while temperature was held constant. What happens? xA increases, yA decreases xA increases, yA increases xA decreases, yA decreases xA decreases, yA increases Vapor yA=0.50 Liquid xA=0.25

  4. One mole of pure hexane is in vapor-liquid equilibrium at 1 bar and 70°C in a piston-cylinder. After 0.2 mole of heptane liquid is injected, the system returns to equilibrium at the same temperature and pressure. What are the final contents of the system? All liquid All vapor Liquid and vapor with yhexane > xhexane Liquid and vapor with yhexane < xhexane Psat(hexane) > Psat(heptane) 0.2 mole Hexane Vapor Heptane(l) Hexane Liquid

  5. One mole of pure hexane is in vapor-liquid equilibrium at 1 bar and 70°C in a piston-cylinder. After 0.2 mole of heptane vapor is injected, the system returns to equilibrium at the same temperature and pressure. What are the final contents of the system? All liquid All vapor Liquid and vapor with yhexane > xhexane D. Liquid and vapor with yhexane < xhexane Psat(hexane) > Psat(heptane) 0.2 mole Hexane Vapor Heptane (v) Hexane Liquid

  6. Hexane liquid is in equilibrium with N2 gas at 50°C in a piston-cylinder. Some heptane liquid is added to the system at constant temperature and pressure. What happens? Some hexane vapor condenses Some hexane liquid vaporizes All the hexane vapor condenses All the hexane liquid vaporizes No change in the hexane in the 2 phases Psat(hexane) > Psat(heptane) N2 Gas Heptane(l) Hexane Liquid

  7. Hexane liquid is in equilibrium with N2 gas at 50°C in a piston-cylinder. Some heptane vapor is added to the system at constant temperature and pressure. What happens? Some hexane vapor condenses Some hexane liquid vaporizes All the hexane vapor condenses All the hexane liquid vaporizes No change in the hexane in the 2 phases Psat(hexane) > Psat(heptane) N2 Gas Heptane(v) Hexane Liquid

  8. Hexane liquid is in equilibrium with N2 gas at 50°C in a piston-cylinder. Some heptane vapor is added to the system at constant temperature and pressure. What happens? The heptane remains in the vapor phase Some heptane condenses All the heptane condenses All the hexane liquid vaporizes Psat(hexane) > Psat(heptane) N2 Gas Heptane(v) Hexane Liquid

  9. Hexane liquid is in equilibrium with N2 gas at 50°C in a piston-cylinder. Some heptane liquid is added to the system at constant temperature and pressure. What happens? The heptane remains in the liquid phase Some heptane vaporizes All the heptane vaporizes All the hexane liquid vaporizes Psat(hexane) > Psat(heptane) N2 Gas Heptane(l) Hexane Liquid

  10. Two components (A & B) are in VLE in a piston-cylinder container. Initially, 1.0 mol of liquid (xA = 0.4) and 0.1 mole of vapor (yA= 0.7) are present. If 0.5 mole of liquid A is added to the system and it returns to equilibrium at the same temperature and pressure as before: the amount of liquid increases the amount of liquid decreases the concentration of A in the gas phase increases the concentration of A in the liquid phase increases Vapor yA=0.7 Liquid xA=0.4

  11. Two components (A & B) are in VLE in a fixed volume container. Initially, xA = 0.3 and yA = 0.6. 1.0 cm3 of air is injected into the system. The temperature and pressure are constant. The liquid solution is ideal. If liquid and vapor phases are still present, there is _______ before the injection of air. more liquid than less liquid than the same amount of liquid as Vapor yA=0.6 1 cm3 air Liquid xA=0.3

  12. Two components (A & B) are in VLE in a piston-cylinder. One mole of liquid (xA=0.2) is in equilibrium with one mole of vapor (yA =0.6). The liquid phase does not possess an azeotrope.10 mol liquid A are added at constant temperature and pressure. What phase(s) are present at equilibrium? All liquid All vapor More vapor, less liquid, same compositions More liquid, less vapor, same composition More vapor, less liquid, different compositions Vapor yA= 0.6 10 mol A Liquid xA = 0.2 liquid

  13. Two components (A & B) are in VLE at 60oC and 1 bar in a piston-cylinder. One mole of liquid (xA=0.2) is in equilibrium with one mole of vapor (yA =0.6). The liquid phase does not possess an azeotrope. When 0.3 mol liquid B is added at 60oC and 1 bar, what phase(s) are present at equilibrium? All liquid All vapor More vapor, less liquid, same compositions More liquid, less vapor, same composition More vapor, less liquid, different compositions Vapor yA= 0.6 0.3 mol B Liquid xA = 0.2 liquid

  14. Two components (A & B) are in VLE in a fixed volume container. Initially, xA = 0.3 and yA = 0.6. 1.0 cm3 of air is injected into the system. The temperature and pressure are constant. The liquid solution is ideal. If liquid and vapor phases are still present, xA_______. increases decreases remains the same Vapor yA=0.6 1 cm3 air Liquid xA=0.3

  15. Two components (A & B) are in VLE in an adiabatic piston-cylinder. Assume ideal solution and ideal gas. If 0.2 mole of liquid A is rapidly injected into the system, the temperature at equilibrium is _______ before the injection of A. higher than lower than the same as xA = 0.2, yA = 0.7 Vapor yA= 0.7 0.2 mole A liquid Liquid xA = 0.2

  16. Two components (A & B) are in VLE in a fixed volume container with 2 moles vapor and 1 mole liquid. You add 30 moles of liquid B at constant temperature and pressure. This system does not have an azeotrope. What happens? Some liquid evaporates All the liquid evaporates Some vapor condenses All the vapor condenses xA = 0.2, yA = 0.7 30 moles B(l) Vapor yA=0.7 Liquid xA=0.2

  17. Two components (A & B) are in VLE in a fixed volume container with 2 moles vapor and 1 mole liquid. You add 30 moles of vapor A at constant temperature and pressure. This system does not have an azeotrope. What happens? Some liquid evaporates All the liquid evaporates Some vapor condenses All the vapor condenses xA = 0.3, yA = 0.8 30 moles A(v) Vapor yA=0.8 Liquid xA=0.3

  18. A fixed container, with components A and B, is in chemical and phase equilibrium (xA = 0.6, yA = 0.2). For the reaction (A  B), the addition of liquid B _______ the mole fraction of A in the liquid. increases decreases remains the same Vapor yA=0.2 B(l) Liquid xA=0.6

  19. A liquid mixture is in equilibrium in a piston-cylinder system with a gas phase. The N2doesnot dissolve in the liquid. If N2 is removed completely isothermally using a selective membrane at constant pressure, then xA ________. increases decreases remains the same xA = 0.4, xB = 0.6 yA = 0.5, yB = 0.3, and yN2 = 0.2 Vapor yA= 0.5 yN2 = 0.2 N2 Liquid xA = 0.4

  20. A liquid mixture is in equilibrium in a piston-cylinder system with a gas phase. The N2doesnot dissolve in the liquid. If N2 is removed completely isothermally using a selective membrane at constant pressure, then xA ________. increases decreases remains the same xA = 0.4, xB = 0.6 yA = 0.5, yB = 0.3, and yN2 = 0.2 Vapor yA= 0.5 yN2 = 0.2 N2 Liquid xA = 0.4

  21. Water liquid and vapor are in equilibrium in a piston-cylinder. An insoluble polymer containing a salt is in the liquid. The salt slowly diffuses out of the polymer and dissolves in the water. Temperature and pressure are constant. What happens? All the water condenses All the water evaporates Some water condenses Some water evaporates 1 kg Vapor Polymer Water

  22. A container with 5 cm3 of benzene liquid and 1 cm3 of benzene vapor is in equilibrium. You inject 1 cm3 of toluene vapor. Which of the following mole fractions of toluene in the vapor composition at equilibrium will be closest to the correct value: 90 % 50 % 10 % 1 % 1 cm3 Toluene Vapor 1 cm3 Benzene 5 cm3

  23. A fixed-volume tank contains two components in VLE. 1.0 mole of N2 is added. Assume N2 is not soluble in the liquid. The vapor phase is an ideal gas. The amount of component A in the liquid phase ____________. increases decreases stays the same Vapor yA= 0.6 1 mole N2 Liquid

  24. A fixed-volume tank contains two components in VLE. 1.0 mole of N2 is added. Assume N2 is not soluble in the liquid. The vapor phase is an ideal gas. The amount of component A in the vapor phase ____ increases decreases stays the same Vapor yA= 0.6 1 mole N2 Liquid

  25. A fixed-volume tank contains two components in VLE. 1.0 mole of N2 is added. Assume N2 has no solubility in the liquid. The vapor phase is an ideal gas. The partial pressure of component A ________. increases decreases stays the same Vapor yA= 0.6 1 mole N2 Liquid

  26. Acetone and chloroform form a maximum temperature azeotrope. A piston-cylinder contains pure chloroform at 55°C and 0.95 bar. It has 0.9 mole vapor, 0.1 mole liquid. What is the final condition when 0.1 mole acetone is added at constant temperature and pressure? Tb (chloroform) = 60°C @ 0.95 bar Tb (acetone) = 55°C @ 0.95 bar All liquid All vapor Vapor-liquid mixture 0.1 mole Vapor 0.9 mole CHCl3 Acetone Liquid 0.1 mole

  27. 0.1 mole of A vapor is in VLE with 10 mol liquid A at 70°C in a piston-cylinder. After 0.1 mol of liquid B is injected, the system returns to equilibrium at the same temperature and pressure. PAsat= 2 bar ; PBsat=1.3 bar The liquid is non-ideal and the system has a maximumpressure azeotrope. What are the final contents of thesystem? All liquid All vapor Liquid and vapor with yA > xA Liquid and vapor with yA < xA 0.1 mole A 0.2 mole B 10 mole A

  28. 1.0 mole of pure hexane is in VLE at 1 bar and 70°C in a piston-cylinder. After 0.2 mole of octane liquid is injected, the system returns to equilibrium at the same temperature and pressure. If octane has a lower vapor pressure than hexane, what are the final contents of the system? All liquid All vapor Liquid and vapor with yhexane > xhexane Liquid and vapor with yhexane < xhexane Hexane Vapor Hexane Liquid

  29. A binary mixture is in VLE in a piston-cylinder with 10x more moles in the vapor phase than in the liquid phase with yA = 2xA. You push down on the piston until the volume is half its original value. Temperature is constant. What happens? Pressure increases Pressure remains the same All vapor condenses, pressure is constant All vapor condenses, pressure is higher Nothing changes

  30. A binary mixture is in VLE in a piston-cylinder with 10x more moles in the vapor phase than in the liquid phase with yA = 2xA. You push down on the piston until the volume is half its original value. Temperature is constant. What happens? Vapor and liquid at same pressure Vapor and liquid at higher pressure Some vapor condenses xA increases, yA decreases xA and yA increase

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