2016 Basics – Afternoon: Compilation of my own answers and those discussed by netizens【Hurry up and join the discussion!】 ! ! ! ! ! 】
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This post was last edited by d220916 on 2016-9-8 at 13:04; I want to see how many points I can get. . . I think I’ve already gotten 10 questions right. . . . . Those who know the answer, please point out what is incorrect. Everyone is welcome to discuss. (Discussion by everyone) indicates that opinions have been aligned. (Doing it oneself) means one thinks it’s possible, but there might be mistakes. (Guessing) means making a random choice. (Controversial) means that there is uncertainty after discussion. I would like to thank the other 3 posts for the materials they provided. 1. Methane density C 0.647 (calculate by yourself) 2. Which partial derivative is incorrect? A 3. The entropy change in the Carnot cycle for real gases: C is equal to zero (discuss among everyone) 4. The chemical formula for water and ice: B = 5. The standard equilibrium constant for ammonia decomposition: C 0.5 (calculate by yourself) 6. The number of components in iodine and steam: B 1 (discuss among everyone) 7. The molar conductivity of sulfuric acid solution: A increases (discuss among everyone) 8. The ion concentration of sodium sulfate: A (b2·b)1/3 (discuss among everyone) 9. Intermolecular forces in liquids and surface tension: A increases (discuss among everyone) 10. Half-life of a zero-order reaction: C CA,0/2k 11. Catalyst and rate constant: C 2k 12. AgI colloidal particles: A are positively charged (controversial) 13. Shaft power: B 3.72 14. Gauge pressure in a container with density: B 246.2 15. Working principle of centrifugal pumps and vortex pumps: A is dynamic type 16. Filtration constant: C 5.52 17. Sphericity of a cube: C 0.806 18. Stokes’ law for sedimentation: C is negative power 1 19. Convection and diffusion in stirred tanks: A is macroscopic (large scale) 20. Heat transfer in multi-layer flat walls: To ignore C, contact thermal resistance 21. Equation for convective heat transfer rate: B Newton’s law of cooling 22. Heating crude oil with steam: A is crude oil 23. Doubling the flow rate in a heat exchanger: B 2^0.8 24. Concentration by evaporation: D 3200 25. For dynamic △y2: B 0.000888 26. Solvent absorption rate: A 81.6 27. 1.578 times the minimum amount; initial molar ratio: D 0.292 28. Gas phase composition: 0.785; corresponding liquid phase composition: C 0.613 29. Azeotropes: A require special distillation methods 30. Saturated steam feed; liquid-to-gas ratio: C 0.822 31. Operating flexibility: B 4.03 32. Air humidity: A 0.010 33. Dew point: A is lower than the dry-bulb temperature 34. Surface temperature during constant-rate drying: C remains unchanged 35. K=1.5; Ya= C 0.644 (I forgot what I calculated back then) 36. Extraction using only gravity: B sieve tray extractors (discuss among everyone) 37. Resistance of Pt100 at D 0℃ (discuss among everyone) 38. Conversion of analog signals to digital signals: C analog-to-digital conversion 39. Integral controller: A 0.2mA (guessing) 40. Tuning of control parameters: C the one with the most characters 41. Engineering design includes A concepts and construction drawings 42. Project proposals do not include D detailed technical and economic analysis 43. Heat released: A. 7.8944 The process flow diagram does not include C45. Floating-head tube heat exchangers; C46. Appropriate pipeline layout considerations; B47.D50 C15000 (for discussion); 48. Equipment renewal; A. Accelerated depreciation; 49. Polymer materials; C. Adsorption and cross-linking; 50. Risk prevention; B; 51. Diffusion silencers; D. Emission of pressurized gases; 52. Unit of R: B, J mol-1 k-1; 53. Entropy change: A. Positive; 54. Equation of state: C. PR, SRK; 55. Ideal solutions: B. Benzene, toluene; 56. Activity coefficient: B; 57. Light components; Heavy components: A. Y1>X1, Y2
2. Which partial derivative is incorrect? A
Some of them are still open to discussion, but thanks anyway!
Yeah. Some of them I did by trial and error on my own. Actually, I’m satisfied if I can get 70 points. But I’m afraid I won’t be able to get 70 even in the morning. Sigh.
After you have discussed and finalized each item. I’ll update it as the correct answer.
3. It should be option C – it has nothing to do with the medium (I got this question wrong too: lol)； 14. Why is the gauge pressure 246.2? Was the height difference not taken into account in the calculation? 16. K is proportional to (1-S) of the pressure difference; the answer is correct ； 32. Humidity does not change with temperature; the humidity calculated based on the initial temperature should be the answer. My personal calculation gives B, so please discuss this. 41. The question refers to engineering design, while the textbook talks about preliminary design and construction drawing design; therefore, I believe option A is the appropriate choice ； 44. Tends to C ； 59. There are two opinions: one is based fundamentally on the constitution, and the other on the Environmental Protection Law; I chose C. The others basically all support the original poster
2. It is believed that A should be chosen; U is a state function, and whether under constant pressure or constant volume, a change in temperature will result in a change in U.