The sketch should be as realistic as possible. It should be done to scale and no

Question

The sketch should be as realistic as possible. It should be done to scale and not only show the positions of the spot but their sizes and relative darkness as well CALCULATION: Show one full example of Rr calculation for authentic caffeine below. Summarize the rest ofthe results in Table 3, Calculate the % crude caffeine recovery (Assume that each tea bag contains approximately 34 mg of caffeine). f for A.c distenee traveled by cstobke - tana raveledstuevt 3.scm- e CoveyA Acho! % reco very ?.c recovered o osX.xu002?73.5% erude 0. O 63 veco verea 2

Explanation / Answer

4) Caffeine can be obtained from tea leaves by both solid-liquid and liquid-liquid extraction. The percent yield and percent recovery can be calculated by using the final amount of caffeine obtained and by using the known value of caffeine in the tea leaves taken. The percent recovery demonstrates how much of the pure crude caffeine is recovered. The percent error tells you about by how much margin the product has deviated from the expected value. A 100% recovery cannot be obtained because of the material loss during any material transfer during the experiment conducted. A 70-90 % recovery is considered a very good extraction and usually, around 50 and 60% is obtained. And for purity, the error up to 40-50 % is acceptable and low values are much appreciated. Hence, a 60% and above purity is a good yield.

Percentage Error = (Expected weight - Obtained weight/ Expected weight) x 100% (of caffeine)

% Recovery= (Obtained weight / Expected weight) x 100

5) The Direct–Solvent Based Process

When dichloromethane is used to extract caffeine from coffee the solvent actually touches the coffee beans and when used at large amounts there are its health consequences.

In this method, the coffee beans are boiled and then they are repeatedly rinsed with ethyl acetate rather than using dichloromethane. The caffeine and the solvent mixture is then drained away and the beans are steamed to remove any solvent left as a residue. This is also called the natural decaffeination method.

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