Chem 235 Lab Exam
1. What is distillation?
2. How do Distillation an Refluxing differ
3. When is it down to use distillation? (2)
4. List 3 conditions for a successful Sistillation
5. What is b.p by def.
6. What is an Azeotrope?
7. What is one assumption we are making when we are doing simple distillations?
8. What is fractional Distillation?
9. What is the refractive index?
10. What is it caused by?
11. What does the value you get (a constant) for refactive index depend on? (2)
12. Formula on page 14 13. in a condenser what way does the flow of water go (i.e. is water in on the bottom
14. what does the boiling chip do?
15. What is the optimal drop rate of condensate into receiver?
16. What can you do to prevent heat loss?
17. Why do you record temp every 2mL during distillation?
18. What is the point of 10 mL fraction and 30 ? th
19. How do you measure the total volume lost during the distillation?
20. Define Azeotrope
21. Boiling point
24. Slurry (lol)
25. Volatile 26. When is liquidliquid extractions used?
27. What is it based on?
28. Pretend you wanna separate a mix of 2 solids by liquid liquid extraction what
characteristics would your 2 solvents need to have (3)
29. In what solvent is the compound you styingndo extract more soluable in during
your extraction via sep funnel (1 or 2 )?
30. What is successive extractions?
31. What is the max occupancy of a sep funnel?why?
32. How long do you shake and release pressure from a sep funnel for?
33. What is emulsion
34. How do u get rid of it?
35. How long do you let soln dry for after adding drying agent?
36. Alkaline 37. Anhydrous
38. Drying agent
42. Percentage recover
43. Successive extractions
44. When is recrystallization used?
45. How is melting point determined?
46. What do impurities do to a compounds mp?
47. How do u take mp of a known substance?
48. How do u take mp of unknown substance?
49. How do u prepare samle for fisherjohns? 50. How do u prepare sample for melTemp?
51. What is ideal temp riseing rate when u are within 1520 of expected mp on fisher
52. What does y=mx+b stand for?
53. What what cant TLC be used with __________ (compounds)
54. Why would the least polar substance move further up than the more polar
substance on a TLC plate
55. Why is TLC used?(5)
56. What are TLC plates made of?
57. What does Schlierien lines represent?
58. When do u noe both compounds are soluble/partially soluble?
59. When u noe its insoluble?
60. What is a solvent pair? 61. Percent recovery =
62. Percent yield =
63. Schlierien lines=
64. Solvent pair=
66. Is the organic layer the top or bottom layer?
67. What is recrystallization based on?
68. What are the basic requirements of a good solvent for recrystallization?(4)
69. When is a solvent pair used?
70. What is a solvent pair?
71. When is hot filteration preformed? (2)
72. Why are th