Chem 235 Lab Exam 1. What is distillation? 2. How do Distillation an ...
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 or top?) 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 10th mL fraction and 30th?
19. How do you measure the total volume lost during the distillation?
20. Define Azeotrope 21. Boiling point 22. Condentat/Distillate 23. Deistillation 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 trying to extract more soluable in during your extraction via sep funnel (1st or 2nd)?
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 39. Emulsion 40. Extraction 41. Immiscible 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 johns
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= 65. Yield= 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 the funnel and erlenmeyr flask heated during a hot grav. Filt.?
73. When is Norit used?
74. How much of and why is Celite used with Norit? Questions from final fall 2011 Why cnt u use pen on a TLC plate Solvent will bring up the ink whereas the solvent won’t bring up the graphite from a pencil. How can u prevent streaking Page I20 Fill that chart out from extrations (one with salt of …) 28 t/f theritical yield is rarely 100% False u r given a sample “a” and u think it is acetic acid b/c they have same m.p how can u determine it is or isn’t give u ways and how do u do em? Use TLC with at least two different developing solvents, and if they have identical Rf values. How do u oe u added enouf drying egent give an example of one used this year You swirl and if you see chunks at the bottom then you have not added enough. If some of the agent flows freely then you have added enough. Example: Anhydrous Magnesium/Sodium Sulfate. Give 3 things that make a solvent good for extractions Pg 21 How do u noe if something is partially soluble Why didn’t u use a thermal well when doing one of the experiments (I cnt rember which one it was) but u used an ice bath and hot water bath instead? Because Hydrogen gas is a by product, it is dangerous as it is highly flammable so we use hot water bath. Grenigard agent can act as a strong base t/f? T Why do u use a condenser? You use a condenser so that you can collect the vapor by cooling the gas into liquid. For reflux, same container, distillation, different container. We used ether a shit load of times what is its name Diethyl ether. Where do u dispose of acetone? Separate container so that they can reuse acetone. that glass where with a melted organic compound in it for fisher johns? Micro cover glass. And shit used in the experiment that smells like banana’s and is the bee attack fairmone. Isoamyl Acetate made from isoamyl alcohol and acetic acid. And ders this one ques where they tell u the rf values of 3 dif things and give u 3 tlc plates and tell u to draw the position of the dots. So in first one u just label a,b,c but in second one they tell u that experiment is only done ½ way so u have to noe how high the
dots go, and third TLC plate they tell u experiment is complete so I thought u just plot the 3 rf values given but I may be wrong. Don’t relly ask definitions Ask u how to separate 2 things liquidliquid extraction/ fractional distillation One ques u need to be able to estimate the Rf value based on image they give u (basically image is what u see when u look throught that funky microscope and u turning nobs to get Rf value) 1.4252 Noe how to roter vap and the order u do shit in forward n reverse They ask u how to distill so u have to noe when and why u add shit through top of condenser, and what too look for b4 u add 2nd solvent Why and how do u create a solvent pair I20, 63 They gonna give u 2 compunds and ask u which layer is top n bottom and then they gonna b like there is also a acid n base present r they gonna b on the top with it or bottom. Whats the formla of ether – C4H10O I cnt rember more but after ur final write down questions u rember and pass it on to nxt years kids
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 or top?) 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 10th mL fraction and 30th?
19. How do you measure the total volume lost during the distillation?
20. Define Azeotrope 21. Boiling point 22. Condentat/Distillate 23. Deistillation 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 trying to extract more soluable in during your extraction via sep funnel (1st or 2nd)?
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 39. Emulsion 40. Extraction 41. Immiscible 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 johns
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= 65. Yield= 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 the funnel and erlenmeyr flask heated during a hot grav. Filt.?
73. When is Norit used?
74. How much of and why is Celite used with Norit? Questions from final fall 2011 Why cnt u use pen on a TLC plate Solvent will bring up the ink whereas the solvent won’t bring up the graphite from a pencil. How can u prevent streaking Page I20 Fill that chart out from extrations (one with salt of …) 28 t/f theritical yield is rarely 100% False u r given a sample “a” and u think it is acetic acid b/c they have same m.p how can u determine it is or isn’t give u ways and how do u do em? Use TLC with at least two different developing solvents, and if they have identical Rf values. How do u oe u added enouf drying egent give an example of one used this year You swirl and if you see chunks at the bottom then you have not added enough. If some of the agent flows freely then you have added enough. Example: Anhydrous Magnesium/Sodium Sulfate. Give 3 things that make a solvent good for extractions Pg 21 How do u noe if something is partially soluble Why didn’t u use a thermal well when doing one of the experiments (I cnt rember which one it was) but u used an ice bath and hot water bath instead? Because Hydrogen gas is a by product, it is dangerous as it is highly flammable so we use hot water bath. Grenigard agent can act as a strong base t/f? T Why do u use a condenser? You use a condenser so that you can collect the vapor by cooling the gas into liquid. For reflux, same container, distillation, different container. We used ether a shit load of times what is its name Diethyl ether. Where do u dispose of acetone? Separate container so that they can reuse acetone. that glass where with a melted organic compound in it for fisher johns? Micro cover glass. And shit used in the experiment that smells like banana’s and is the bee attack fairmone. Isoamyl Acetate made from isoamyl alcohol and acetic acid. And ders this one ques where they tell u the rf values of 3 dif things and give u 3 tlc plates and tell u to draw the position of the dots. So in first one u just label a,b,c but in second one they tell u that experiment is only done ½ way so u have to noe how high the
dots go, and third TLC plate they tell u experiment is complete so I thought u just plot the 3 rf values given but I may be wrong. Don’t relly ask definitions Ask u how to separate 2 things liquidliquid extraction/ fractional distillation One ques u need to be able to estimate the Rf value based on image they give u (basically image is what u see when u look throught that funky microscope and u turning nobs to get Rf value) 1.4252 Noe how to roter vap and the order u do shit in forward n reverse They ask u how to distill so u have to noe when and why u add shit through top of condenser, and what too look for b4 u add 2nd solvent Why and how do u create a solvent pair I20, 63 They gonna give u 2 compunds and ask u which layer is top n bottom and then they gonna b like there is also a acid n base present r they gonna b on the top with it or bottom. Whats the formla of ether – C4H10O I cnt rember more but after ur final write down questions u rember and pass it on to nxt years kids
