ORGANIC CHEMISTRY 245 Final lab quiz

50 pts.

1.) You carried out a synthesis to produce butyl ketal from the following reaction:

(MW = 58.09 amu) (MW = 74.14 amu) OH-1 (MW = 188.35amu) (MW = 18.02 amu)

CH3-COCH3 + 2 CH3-CH2-CH2-CH2-OH ———-( CH3-C (OCH2-CH2-CH2-CH3)2CH3 + H2O

Acetone butyl alcohol butyl ketal

You weigh out 5.30 g of acetone and react with 6.12 g of butyl alcohol to produce 4.81 g of butyl ketal, what is the % yield of butyl ketal?

2.) You carry out an extraction to separate an organic acid, base and neutral molecule. You weigh out 0.987 g of sample and after extraction / solvent evaporation; your collection was 0.250 g of acid, 0.277 g of the base and 0.421 g of neutral. What are the % recoveries of the organic acid, base and neutral?

Was the entire original sample recovered, if not what was the total % recovery?

3.) You have 25 g of an impure mixture of A + B (17 g of A and 8 g of B). What will be the % recovered for A if you crystallize this sample completely based on the solubility below.

A = 0.75 g / 100 mL at 20°C and 20 g / 100 mL at 100°C

B = 1.10 g / 100 mL at 20°C and 25 g / 100 mL at 100°C.

4.) What is the distillation process?

Name and describe the different types of distillation

5.) How much sample is recovered in the organic phase if 20 g of organic is dissolved in a 150 mL of water? Corg /CH2O = 25 using 3/ 50 mL washes of organic solvent?

6.) You carry out a TLC experiment for an analgesic drug. You use a 20 cm TLC plate and your mobile phase migrated 18 cm up the plate. If you have three components that migrated 3.8 cm (A), 7.6 cm (B) and 13.5 cm(C), what are the retardation factors for these components? If the mobile phase is nonpolar, which component (A, B, or C) would be mostly nonpolar and which would be mostly polar?

7.) What is chromatography and name the different types of chromatography?

How would you rate the elution order of an ether, carboxylic acid, an alcohol, an alkane through a C18 (very non polar) column using a water / acetonitrile (polar) mobile phase?

When ranking the elution order, consider which functional group will have a greater affinity for the mobile phase and rank (these will come out first) and the mobile phase (these will come out last)

ROR = ether

CnH2n+2 = alkane

R-CO2H = carboxylic acid

R-OH = alcohol

R = carbon bond.

Bonus (5.0 pts):

Choose any bonus to answer.

1.) Draw the crystallization graph displaying the profile of a good solvents / poor solvents. Label axis correctly.

2.) Draw the graphs displaying a good distillation and poor distillation (fractional / simple distillation). Label axis correctly.

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