Question

Calculate the maximun percet recovery of caffeine with the given information.

Caffeine solubility in water is: 2.2 mg/mL at 25°C; 180mg.mL at 80°C; 670 mg/mL at 100C.

two vivarine tables each containing 20mcg, a total of 400mcg or 0.4g of caffeine. This technique of extractions utilizes a separatory funnel----->the total recovery was 0.16g

The procedure was:

Obtain 2 Vivarin tablets and crush them using pestle (the total caffeine in the two tablets where 0.4g)

Combine pills, 60mL distilled water, and 8g sodium carbonate

Allow solution to cool once filtered into separatory funnel (15 minutes)

Once cool, add 8 mL dichloromethane to separatory funnel and agitate/oscillate, venting every other turn to allow internal gases to escape

Allow solution to separate. Save bottom layer – DCM layer – and water layer – top – in separate beakers

Take DCM layer and replace in separatory funnel – again add 8mL DCM and agitate (collect and repeate two more times)

There will be water dissolved in the CH2Cl2 extracts that needs to be removed.

Answer 1

Answer :-     

Given 2 vivarine tablets

each has = 0.2 g of caffeine.

So 2 will have 0.4 g of caffeine

This technique of extraction utilizes a seperatory funnel by which 0.16g was recovered

percent recovery = recovered / initial amount x 100

= 0.16 (recovered) / 0.4 (initially) x 100

= 0.16 / 0.4 x 100

= 0.4 x 100

= 40%