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ConcepTests in Chemical Engineering Thermodynamics Unit 3: Fluid Phase Equilibria in Mixtures

ConcepTests in Chemical Engineering Thermodynamics Unit 3: Fluid Phase Equilibria in Mixtures. Day 38.

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ConcepTests in Chemical Engineering Thermodynamics Unit 3: Fluid Phase Equilibria in Mixtures

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  1. ConcepTests in Chemical Engineering ThermodynamicsUnit 3: Fluid Phase Equilibria in Mixtures

  2. Day 38 38.___ Recall, eij = (eii * ejj )½ (1- kij )1. Which (A or B) corresponds to kij > 0?2. Which corresponds to components “liking” each other?3. Which corresponds to a higher fugacity mixture?4. Which will give the highest bubble point pressure?

  3. Day 39 VLE Intro 39.1. Components (A and B) are in VLE. One mole of liquid (xA=0.4) and 0.1 mol of vapor (yA=0.7) are present. When 0.5 mol of A is added and the system goes to equilibrium at the same T and P, what happens? (cf. Falconer, CEE 38:64, 2004) (a) The amount of liquid increases.(b) The amount of liquid decreases.(c) The concentration of A in the gas phase increases.(d) The concentration of A in the liquid phase increases.

  4. Day 39 VLE Intro 39.2. The fugacity (bar) of water at 150C and 100 bar closer to ___. (cf. Falconer, CEE 38:64, 2004) (a) 1(b) 5(c) 50(d) 100

  5. Day 39 VLE Intro 39.3. Two identical flasks at 45C are connected by a thin tube. Flask A contains water and flask B contains the same amount of a 95/5 mixture of water and salt. After 5 hours ___. (cf. Falconer, CEE 38:64, 2004) (a) Flask A has more water.(b) Flask B has more water.(c) The amounts of water do not change since they are at the same temperature.(d) All the salt moves to flask A.

  6. Day 39 VLE Intro 39.4. Estimate the equilibrium partial pressure of ethanol (bars) in air above a solution of 50mol% ethanol and water at 311K. You may assume an ideal solution and apply the shortcut vapor pressure equation. (Tc=516,Pc=6.4,w=0.64) (a) 0.1(b) 0.2(c) 0.4(d) 0.8

  7. Day 40 VLE Intro 40.1 Ethanol has a lower flammability limit (LFL) of 4.3%. What concentration (mol%) of ethanol in water is necessary for the solution to burn at 311K (assume IS thermo). (a) 0.1(b) 0.2(c) 0.4(d) 0.8

  8. Day 42 EOS VLE 42.1 The equation of state below has been suggested for a new equation of state. Derive the expression for the Helmholtz energy departure (A-Aig)TV/RT.Z = 1 + 4b/(1-b) where b = xibi (a) 4/(1-b) (b) (-4/bi)/(1-b)(c) (-4/bi)*ln(1-b) (d) -4ln(1-b)

  9. Day 42 EOS VLE 42.2 The equation of state below has been suggested for a new equation of state. Derive the expression for the fugacity coefficient ln(fk).Z = 1 + 4b/(1-b) where b = xibi (a) 4b/(1-b) – ln(Z)(b) -4ln(1-b) – ln(Z)(c) 4bk/(1-b) – ln(Z) (d) -4ln(1-b) + 4bk/(1-b) – ln(Z)

  10. Day 43 QikQiz3.1 43.1 The equation of state below has been suggested for a new equation of state. Derive the expression for the Helmholtz energy departure (A-Aig)TV/RT.Z = 1 + 4b/(1-b) where b = xibi (a) -4/(1-b)2(b) 4ln(1-b) (c) -2ln(1-b) (d) -4ln(1-b)

  11. Day 43 QikQiz3.1 43.2 The equation of state below has been suggested for a new equation of state. Derive the expression for the fugacity coefficient ln(fk).Z = 1 + 4b/(1-b) where b = xibi (a) -4ln(1-b) - 4bk/(1-b) – ln(Z)(b) -4ln(1-b) + 4bk/(1-b) – ln(Z)(c) 4bk/(1-b) – ln(Z) (d) -4bk/(1-b) – ln(Z)

  12. Day 43 QikQiz3.1 43.3 Estimate the bubble pressure (MPa) of acetone(1,MW=58) + nPentane(2,MW=72) at 32.0C and 21wt% acetone from the ideal shortcut model. The shortcut vp’s are: P1sat =0.044, P2sat =0.090 MPa (a) 0.1013(b) 0.0530(c) 0.0790(d) 0.0810

  13. 43.4 For liquid acetone(1)+nPentane(2), br = 0.786 at 305K and 25mol% acetone. Estimate the Z-factor from the vdW model assuming kij=0.FYI: aii [=] J2/(kmol2-MPa); bi [=] J/(mol-MPa)amix = 2.061 ; bmix = 137 (a) 0.0001(b) 0.001(c) 0.01(d) 0.1

  14. 43.5 For liquid acetone(1)+nPentane(2), br = 0.786 at 32.0C and 25mol% acetone. Estimate the liquid fugacity coefficient of acetone from the vdW model assuming kij=0.FYI: aii [=] J2/(kmol2-MPa); bi [=] J/(mol-MPa)amix = 2.061 ; bmix = 137 (a) 0.0015(b) 0.015(c) 0.15(d) 1.5

  15. 43.6 The bubble pressure of acetone(1)+ nPentane(2) is 0.525 bars at 32.0C and 82mol% acetone and acetone’s liquid fugacity coefficient is 0.77 from the PREOS model. Estimate the K-value for acetone assuming the vapor phase can be treated as an ideal gas. Day 43 QikQiz3.1 (a) 0.2(b) 0.4(c) 0.6(d) 0.8

  16. Day 47 QikQiz3.2 47.1 The equation of state below has been suggested for a new equation of state. Derive the expression for the Helmholtz energy departure (A-Aig)TV/RT.Z = 1/(1-2b) where b = xibi (a) -2ln(1-2b) (b) 2ln(1-2b) (c) -ln(1-2b) (d) 2/(1-2b)2

  17. 47.2 The equation of state below has been suggested for a new equation of state. Derive the expression for the fugacity coefficient ln(fk).Z = 1/(1-2b) where b = xibi Day 47 QikQiz3.2 (a) -ln(1-2b) –2bk/(1-2b)– ln(Z)(b) -ln(1-2b) + 2bk/(1-2b)– ln(Z)(c) -2ln(1-2b) + 2bk/(1-2b) – ln(Z)(d) 2ln(1-2b) – 2bk/(1-2b) – ln(Z)

  18. 47.3 The bubble pressure of acetone(1)+nPentane(2) is 1.013 bars at 32.0C and 21wt% acetone. Estimate the kij find the inferred azeotropic composition of the PREOS model. Indicate the composition below. Day 47 QikQiz3.2 (a) 0.20(b) 0.25(c) 0.30(d) 0.35

  19. 47.4 The bubble pressure of acetone(1)+nPentane(2) is 1.013 bars at 32.0C and 21wt% acetone. Estimate the bubble pressure from the ScHil model assuming kij=0. Day 47 QikQiz3.2 (a) 0.0270(b) 0.0790(c) 0.0870 (d) 0.1013

  20. 50.1 An azeotrope exists for n-butane(1)+ethyleneOxide(2) at 1.013 bars at -6.5C and 78wt% butane. Estimate the azeotropic composition in vol% butane. Day 50 Activity Models (a) 70(b) 75(c) 80 (d) 85

  21. 50.2 An azeotrope exists for n-butane(1)+ethyleneOxide(2) at 1.013 bars at -6.5C and 78wt% butane. Estimate the activity coefficient of EtO (g2) at the azeotropic composition and temperature from the ScHil model assuming kij=0. Day 50 Activity Models (a) 0.04(b) 1.06(c) 1.98 (d) 2.89

  22. 50.4 An azeotrope exists for n-butane(1)+ethyleneOxide(2) at 1.013 bars at -6.5C and 78wt% butane. Estimate the vapor pressure (mmHg) of butane at the azeotropic composition and temperature. Day 50 Activity Models (a) 755(b) 626(c) 588 (d) 397

  23. 50.5 An azeotrope exists for n-butane(1)+ethyleneOxide(2) at 1.013 bars at -6.5C and 78wt% butane. Estimate the bubble pressure (mmHg) at the azeotropic composition and temperature from the ScHil model assuming kij=0. Day 50 Activity Models (a) 820(b) 790(c) 740 (d) 520

  24. 50.4 An azeotrope exists for n-butane(1)+ethyleneOxide(2) at 1.013 bars at -6.5C and 78wt% butane. Estimate the kij that matches the bubble pressure (MPa) at the azeotropic composition and temperature from the ScHil model. Day 50 Activity Models (a) 0.10(b) 0.01(c) -0.01 (d) -0.10

  25. 51.1 An azeotrope exists for n-butane(1)+ethyleneOxide(2) at 1.013 bars at -6.5C and 78wt% butane. Estimate the Antoine coefficients for ethylene oxide from the shortcut eq.(Hint: Use Pc in mmHg to match units of existing coeffs.) Day 50 Activity Models (a) 8.53, 1313, 273.15(b) 7.53, 1313, 273.15(c) 6.53, 1313, 273.15(d) 5.53, 1313, 273.15

  26. 51.2 Some activity models have contributions like:DGE= S Fidi where Fi is the volume fraction and di is the solubility parameter. Derive the contribution to the activity coefficient (lngk) for this contribution to GE. Day 50 Activity Models (a) [ (Fkdk)/xk ] + (SFidi)(1-Fk/xk) (b) Vkdk/( SxiVi ) – Vk ( SFidi )/( SxiVi )2 (c) Vkdk/( SxiVi ) (d) Vkdk2

  27. Qq3.3.1 Some activity models have contributions like:DGE= S Fidi where Fi is the volume fraction and di is the solubility parameter. Derive the contribution to the activity coefficient (lngk) for this contribution to GE. Day 51 QikQiz3.3 (a) [ (Fkdk)/xk ] + (SFidi)(1-Fk/xk) (b) Vkdk/( SxiVi ) – Vk ( SFidi )/( SxiVi )2 (c) Vkdk/( SxiVi ) (d) Vkdk2

  28. Qq3.3.2 An azeotrope exists for acetone(1)+methanol(2) at 1.013 bars at 55.7C and 80mol% acetone. Estimate the kij that matches the bubble pressure (MPa) at the azeotropic composition and temperature from the ScHil model. Day 51 QikQiz3.3 (a) 0.10(b) 0.05(c) -0.05 (d) -0.10

  29. Day 51 QikQiz3.3 Qq3.3.3 An azeotrope exists for acetone(1)+methanol(2) at 1.013 bars at 55.7C and 80mol% acetone. Compute the experimental value for the activity coefficient of methanol at the azeotrope. (a) 3.1(b) 1.6(c) 1.4 (d) 0.7

  30. Day 51 QikQiz3.3 Qq3.3.4 An azeotrope exists for acetone(1)+methanol(2) at 1.013 bars at 55.7C and 80mol% acetone. Compute the van Laar parameter A21 that matches the azeotrope. (a) 0.35(b) 0.45(c) 0.55 (d) 0.65

  31. 52.1 Making your best estimate, arrange the following mixtures from most ideal to least ideal (1) Pentane+hexane, (2) decane+decalin, (3) 1-hexene+dodecanol, (4) pyridine+methanol, (5) diethyl ether+n-heptane. Day 52 Activity Models (a) 1, 2, 3, 4, 5 (b) 1, 2, 5, 3, 4(c) 5, 4, 1, 2, 3 (d) 2, 1, 5, 4, 3

  32. 355 V 350 (A) 345 T(K) 340 335 L 330 0 0.2 0.4 0.6 0.8 1 x1-y1 52.2 Which of the following properly depicts a maximum boiling azeotrope? Day 52 Activity Models

  33. 52.3 Suppose the activity coefficients of all components in a mixture are greater than unity. Is the Gibbs Excess energy for this mixture positive, negative, or zero? Why? Day 52 Activity Models (a) positive (b) negative(c) zero (d) don’t ask a mouse

  34. 52.4 Use UNIFAC(VLE) to predict the activity coefficient of para-methylPhenol (structure below) in water at infinite dilution and 25C. Day 52 Activity Models (a) 400 (b) 95(c) 45 (d) 30

  35. 52.5 Estimate the infinite dilution activity coefficient for a component in water when the Margules 1-parameter is 2. Day 52 Activity Models (a) 7 (b) 4 (c) 2 (d) 1

  36. Day 53 (/41revisited) 53.___ Recall, eij = (eii * ejj )½ (1- kij )1. Which (A or B) corresponds to kij > 0?2. Which corresponds to components “liking” each other?3. Which corresponds to a higher fugacity mixture?4. Which will give the highest bubble point pressure?

  37. 355 V 350 (A) 345 P(mmHg) 340 335 L 330 0 0.2 0.4 0.6 0.8 1 x1-y1 54.1 Which of the following properly depicts a maximum boiling azeotrope? Day 54 Activity Models

  38. 54.2 We desire the relative volatility of oxygen(1)+ ethyleneOxide(2) at 1.013 bars and 10mol% oxygen. Estimate the Antoine coefficients for ethylene oxide from the shortcut eq. (Hint: Use Pc in mmHg to match units of existing coeffs.) Day 54 Activity Models (a) 8.53, 1313, 273.15(b) 7.53, 1313, 273.15(c) 6.53, 1313, 273.15(d) 5.53, 1313, 273.15

  39. 54.3 We desire the relative volatility of oxygen(1)+ ethyleneOxide(2) at 10 bars and 10mol% oxygen and L/F=1. Estimate the temperature of interest according to the ScHil model with kij=0. (FYI for O2: d~4.0 and r298=0.97) Day 54 Activity Models (a) 298(b) 181(c) 117(d) 45

  40. 54.4 We desire the relative volatility of oxygen(1)+ ethyleneOxide(2) at 10 bars and 10mol% oxygen and L/F=1. Estimate the relative volatility according to the ScHil model with kij=0. (FYI for O2: d~4.0 and r298=0.97) Day 54 Activity Models (a) 298(b) 181(c) 117(d) 45

  41. 55.1 Which of the following is NOT an indicator of possible azeotropic behavior? Day 55 Activity Models (a) similar boiling points(b) similar solubility parameters(c) large activity coefficients(d) positive Gibbs excess energy

  42. 55.2 Which of the following indicates a small value for the solubility parameter? Day 55 Activity Models (a) strong hydrocarbon content (b) a small molecule with a high boiling point(c) strong hydrogen bonding (d) a low critical pressure

  43. P-x P P-y P-x xA, yA P-y P P T P P P-y P-x P-x P-x xA, yA xA, yA xA, yA xA, yA xA, yA T-y P-y P-y T-x 55.2 Which of these diagrams are not possible? A. 2,6 B. 1,4,6 C. 2,5 D. 2,3,5 E. 3,5 3 1 2 5 4 6

  44. 55.4 Components (A and B) are in VLE. One mole of liquid (xA = 0.4) and 0.1 mol of vapor (yA = 0.7) are present. 0.5 mol of A is added and the system goes to equilibrium at the same T and P. What happens?JLF A. The amount of liquid increases B. The amount of liquid decreases C. The concentration of A in the gas phase increases D. The concentration of A in the liquid phase increases yA=0.7 xA= 0.4

  45. 55.3 We desire the relative volatility of oxygen(1)+ ethyleneOxide(2) at 10 bars and 10mol% oxygen and L/F=1. Estimate the relative volatility according to the ScHil model with kij=0. (FYI for O2: d~4.0 and r298=0.97) Day 55 Activity Models (a) 298(b) 181(c) 117(d) 45

  46. Day 56 QikQiz3.4 Qq3.4.1 An azeotrope exists for vinylAcetate(1)+methanol(2) at 1.013 bars at 58.5C and 39 mol% acetate. Compute the experimental value for the activity coefficient of methanol at the azeotrope. The Antoine coefficients for vinylacetate are:A=7.21538 , B=1299.069 , C=226.967 (Hint: Don’t forget Antoine coeffs for methanol.) (a) 0.8(b) 1.3(c) 1.6 (d) 12

  47. Day 56 QikQiz3.4 Qq3.4.2 An azeotrope exists for vinylAcetate(1)+methanol(2) at 1.013 bars at 58.5C and 39 mol% acetate. Compute the van Laar parameter A21 that matches the azeotrope. (a) 0.55(b) 0.95(c) 1.35 (d) 1.65

  48. Day 56 QikQiz3.4 Qq3.4.3 An azeotrope might exist for ethylAcetate(1)+ methanol(2) at 1.013 bars. Use UNIFAC to estimate the infinite dilution activity coefficient of ethylacetate at the bubble point. (a) 0.55(b) 1.35(c) 2.75 (d) 9.65

  49. Day 56 QikQiz3.4 Qq3.4.4 An azeotrope might exist for ethylAcetate(1)+ methanol(2) at 1.013 bars. Use UNIFAC to estimate the relative volatility of methanol (LK) to dilute ethylacetate (HK) at the bubble point. (a) 0.55(b) 1.35(c) 2.75 (d) 9.65

  50. Day 56 LLE Intro 56.1 LLE might exist for nOctane(1)+ methanol(2) at 1.013 bars. Use the ScHil model to estimate the infinite dilution activity coefficient of methanol in nOctane at 25C. (a) 2(b) 3(c) 10 (d) 20

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