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Fugacity

Fugacity. 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. Which of the following will increase the fugacity of a component, A?.

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Fugacity

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  1. Fugacity Contributions by: John L. Falconer & Will MedlinDepartment of Chemical and Biological EngineeringUniversity of ColoradoBoulder, CO 80309-0424 Supported by the National Science Foundation

  2. Which of the following will increase the fugacity of a component, A? Convert from solid to liquid Convert from liquid to solid Decrease pressure Dilute with component B None of the above

  3. What is the driving force for component A to move from liquid to vapor to reach equilibrium? A. PressureB. EntropyC. EnthalpyD. ConcentrationE. Gibbs free energy Vapor yA Liquid xA

  4. One component exists in two phases at the same temperature, but the phases are not in equilibrium. Which phase has the higher fugacity? α β Same fugacity in each phase. Not enough information. 0.1 mol/L α phase 0.5 mol/L ᵦphase

  5. One component exists in two phases at the same temperature, but the phases are not in equilibrium. What is the direction of mass transfer? From α to β. From β to α. No mass transfer occurs. Cannot predict direction. 0.005 mol/L α phase 0.10 mol/L ᵦphase

  6. A B H2O +EtOH H2O Two identical flasks at 45°C are connected by a tube. Flask A contains water and flask B contains 50% more water plus it contains ethanol. As the system approaches equilibrium, _______________________. water moves from A to B ethanol moves from B to A water moves to B and ethanol moves to A both water and ethanol move to A there is no change in solution levels

  7. A B H2O 35°C H2O 40°C Two identical flasks are connected by a tube. Flask A contains water at 40°C. Flask B contains 50% more water at 35°C. As the system approaches equilibrium, _______________. water moves from A to B water moves from B to A no change occurs

  8. A B H2O 40°C H2O 40°C Two identical flasks are connected by a tube. Flask A contains water at 40°C. Flask B contains 50% more water at 40°C. As the system approaches equilibrium, _______________. water moves from A to B water moves from B to A no change occurs

  9. A B H2O 40°C +NaCl H2O 40°C Two identical flasks contain water at 40°C and are connected by a tube. NaCl is added to flask B. As the system approaches equilibrium, ______________. water moves from A to B water moves from B to A no change in levels occur

  10. A B 98% H2O +2% EtOH 55°C H2O 45°C Two identical flasks are connected by a tube. Flask A contains water at 45°C. Flask B contains twice the volume of A but is a 98% H2O/ 2% ethanol mixture at 55°C. As the system approaches equilibrium, _______. water moves from A to B ethanol moves from B to A water moves to B and ethanol to A both water and ethanol move to A no change in levels occur

  11. A B Pure H2O 22oC NaCl Solution 25oC Flask A contains a NaCl solution at 25°C in equilibrium with the pure water at 22°C in flask B. PH2Osat(25°C) = 3.2 kPa PH2Osat(22°C) = 2.6 kPa Estimate the fugacity of water in the NaCl solution. 3.2 kPa 2.6 kPa < 2.6 kPa > 3.2 kPa > 2.6 kPa

  12. A B 80% H2O 45°C +20% NaCl H2O 45°C Two flasks at 45°C are connected by a tube. Flask A contains H2O, and flask B contains the same amount of an 80/20 mixture of H2O and NaCl. After 5 hours, ________. Beaker A has more water Beaker B has more water The amounts of water do not change since they are at the same temperature All the salt moves to beaker A

  13. A B H2O 45°CNaCl + 5 g KCl H2O 45°C NaCl Two flasks at 45°C are connected by a tube. Flask A contains water and NaCl. Flask B contains 50% more water and also contains NaCl. The system is at equilibrium. When 5 g of KCl is added to Flask B, _________________. water moves from B to A water moves from A to B KCl moves from B to A nothing changes

  14. Adsorption concentrates a molecule on a surfacefrom another phase. Consider hexane liquid and vapor. The hexane concentration in the zeolite pores is ____________. higher in A higher in B the same in both Insufficient information B A Vapor Vapor Porous zeolite crystals Liquid Liquid

  15. Two systems have acetone/hexane in vapor-liquid equilibrium at the same temperature. Acetone is enriched in the vapor phase. Both molecules adsorb on the zeolite surface, where they have a higher concentration than in the gas phase. Which arrangement will have a higher concentration of acetone adsorbed on the zeolite crystals? Higher in A Higher in B The same in both Insufficient information A B Vapor 50/50 Vapor Porous zeolitecrystals 50/50 Liquid Liquid

  16. Two systems have acetone/hexane in vapor-liquid equilibrium at the same temperature. Acetone is enriched in the vapor phase. Both molecules adsorb on the zeolite surface, where they have a higher concentration than in the gas phase. Which arrangement will have a higher concentration of acetone adsorbed on the zeolite crystals? Higher in A Higher in B The same in both Insufficient information A B 50/50Vapor Vapor Porous zeolitecrystals Liquid 50/50Liquid

  17. 2 2 P P 1 1 V V As the pressure increases from point 1 to 2, which figure shows an area proportional to the change in Gibbs free energy? A B

  18. f f f f P P P P Which plot represents f vs. P for an ideal gas? A B C D

  19. For the H-xA diagram at 80°C, what is the maximumvalue of the partial molar enthalpy of component Aat 80°C? 50 cal/mol 22 cal/mol 85 cal/mol 100 cal/mol 0 cal/mol 100 100 H (cal/mol) 50 50 0 0 0 0.5 1.0 xA

  20. A B D C E An isotherm for a cubic equation of state is shown below. Which line corresponds to a vapor-liquid equilibrium? Pressure n/V

  21. When both vapor and liquid are present, the fugacity at x1 = 0.1 will be ________ at x1 = 0.3. greater than less than equal to the value P 0.1 0.3 0.5

  22. When both vapor and liquid are present, the fugacity at x1 = 0.1 will be ________ at x1 = 0.3, because ________. greater than; pressure is higher less than; mole fraction is lower less than; partial pressure is higher equal to the value; its at equilibrium. P 0.1 0.3 0.5

  23. 20 bar A metal box of fixed volume contains CO2 at a pressure of 2 bar. Through a valve you add CH4 at a constant rate and at constant temperature. Which plot represents how CH4 fugacity changes with time up to a total pressure of 20 bar? Assume ideal gases. None of the above. 2 bar Time Time Time Time A B C D fugacity 0 bar

  24. A metal box of fixed volume contains CO2 at 2 bar pressure. Methane was added at a constant rate and at constant temperature. Which is the most likely plot of CH4 fugacity vs. time up to a total pressure of 20 bar? Assume ideal gases. A B C D 20 bar 10 bar 2 bar Time Time Time Time

  25. Liquid water is in equilibrium with water vapor and air. Ptot= 1.2 bar PH2O= 0.1 bar The fugacity of water is about __________. 0.1 bar. 1.2 bar. 1.00 (dimensionless). Cannot be determined.

  26. The boiling point of water at 1 bar is 100°C. At 150°C the boiling point is 4.7 bar.The fugacityof water at 150°C and 100 bar is closer to ______ bar. 1 5 50 100

  27. When comparing steam at 100°C to water at 100°C, steam has a higher enthalpy, _______, and ________. higher entropy, higher Gibbs free energy higher entropy, the same Gibbs free energy the same entropy, the same Gibbs free energy lower entropy, lower Gibbs free energy

  28. 1 kg of ice and 1 kg of liquid water are at equilibrium at 0°C. When liquid ethanol is added and the temperature is kept at 0oC, _______________. some ethanol freezes some water freezes some ice melts all the ice melts all the ethanol freezes

  29. Ethanol at 0°C is added to a ice-liquid water mixture at 0°C in an adiabatic container. The temperature of the mixture _______________. decreases increases remains the same

  30. A water/ethanol mixture is at -5°C. You drop an ice cube that was also at -5°C into the liquid. What happens? Nothing happens, the system stays at -5°C Some ice melts All ice melts Some water freezes

  31. Air is bubbled through a tank of water at 25oC and atmospheric pressure. The solubility of O2 in water is about 0.005 mol% at 25oC. Estimate the fugacity of oxygen in the water. 1 bar 0.2 bar 0.5 bar 2 bar 0.0005 bar

  32. A pure-component fluid is at 10 bar and 350 K. The Peng-Robinson equation of state has three real roots: 1) V = 0.080 L/mol ; fugacity = 11 bar 2) V = 8 L/mol ; fugacity = 9 bar The fluid is a ____________. liquid gas 2-phase mixture supercritical fluid

  33. A pure-component fluid is at 10 bar and 350 K. The Peng-Robinson equation of state has three real roots: 1) density = 25 mol/L; fugacity = 11 bar 2) density = 0.2 mol/L; fugacity = 9 bar The fluid is a ____________. liquid gas 2-phase mixture supercritical fluid

  34. Boiling point of water: Psat= 1.0 bar; Tsat= 100°C Psat= 4.7 bar; Tsat= 150°C The fugacity of water at 150°C and 100 bar is closer to __________. 1 bar 5 bar 50 bar 100 bar

  35. Which of the following will increase the fugacity of a component, A? Convert from solid to liquid Convert from liquid to solid Decrease pressure Dilute with component B None of the above

  36. If you were to boil water on a stove in a small room for an hour, the fugacity of the ______________. liquid increases water vapor increases liquid decreases water vapor decreases water stays the same in the vapor H2O

  37. Soda (liquid water with a low concentration of dissolved CO2) at 0°C is compressed to 5 bar soonly a liquid phase remains. In the liquid phase, the fugacity of ___________. water is higher CO2 is higher water and CO2 are the same

  38. A can of soda at 0°C contains liquid water with a low concentration of dissolved CO2. If the CO2 pressure in the can is slightly above 1 bar, which has a higher fugacity in the liquid phase? Water CO2 Fugacities of water and CO2 are equal

  39. When salt is added to pure water, what happens to the fugacity of the water? increases decreases stays the same

  40. Pure NaCl was added to pure water until thewater was saturated and the excess salt settled to the bottom of the container. What happened to the fugacity of the salt? Increased Decreased Did not change

  41. Compared to the fugacity of pure water, the fugacity of water in a saline solution will be _________. higher lower the same

  42. Pure NaCl was added to pure water until thewater was saturated and the excess salt settled to the bottom of the container. The fugacity of the dissolvedsalt is __________ the fugacity of the pure NaCl. higher lower the same as

  43. A liquid containing 60 mol% salt and 40 mol% water is in equilibrium with water vapor at 0.5 bar. Which species has the higher fugacity in the liquid? Salt Water Their fugacities are equal Need more information

  44. A sealed container of water is at high enough pressureso that no vapor is present. The water contains 0.2 mol% salt and 0.2 mol% CO2. Which component has the highest fugacity? Water CO2 Salt Same for all

  45. In a bubble pressure calculation using a EOS, the mole fractions of liquid are known, and the mole fractions of vapor must be calculated by iteration by guessing the pressure. After the first iteration, Syi > 1. For the next iteration, _______________. raise the pressure lower the pressure keep the pressure the same but change the composition

  46. A EOS spreadsheet is used to calculate VLE for a binary mixture (x1= 0.9) with a non-ideal liquid phase and a non-ideal gas. Which statement about the fugacity coefficients is most likely to be correct? = = < >

  47. Which of the following statements is NOT true at an azeotrope? xA = yA xA = xB None of the above

  48. At VLE, Which is the correct equation to use when solving for the liquid phase fugacity of component 2 using an equation of state? x2g2P x2f2LP x2f2LPsat x2g2Psat None of the above

  49. Which of the following statements is NOT true at an azeotrope? xA = yA None of the above

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