Extraction Of Caffeine Lab Template (Page 8 of 8) in pdf

Extraction Of Caffeine Lab Template Page 8

Extraction of Caffeine

Postlab

Name_______________

1. On the report sheet you calculated your percent recovery of caffeine.

 If your percent was less than 100%, give at least one reason why it was less than 100%.

 If your percent was more than 100%, give at least one reason why it was more than

100%.

Do NOT simply say “human error.” Be specific about the types of errors (human or otherwise)

that may have occurred, leading to a recovery that is not exactly equal to 100%.

2. Based on what you observed during this experiment, is dichloromethane denser OR less

dense than water? Explain your reasoning.

Based on what happened in this experiment, is caffeine more soluble in water, OR more soluble

in dichloromethane? Explain your reasoning.

3. Ethanol is miscible with water. (After all, alcoholic beverages don‟t separate into an “alcohol

layer” and a “water layer.”) Assuming that caffeine is soluble in ethanol, could you use ethanol

as a solvent to extract caffeine from coffee (rather than using dichloromethane as the extraction

solvent)? Explain why or why not.

4. A 12 oz can of Coke contains 46 mg of caffeine. One fluid ounce is equivalent to 29.57 mL

(1 oz = 29.57 mL). What is the concentration of caffeine in Coke, in units of mg/mL? Show your

work.

Extraction Of Caffeine Lab Template Page 8