Suppose caffeine has a partition coefficient of 2.5 between dichloromethane and water (2.5/1 = dichloromethane/water). you are given a solution of 10 grams of caffeine dissolved in 100 ml water. you extract your caffeine solution 1 x 100 ml dichloromethane, and evaporate your dichloromethane layer. how much caffeine would you expect to isolate? a) 8.0 grams b) 7.5 grams c) 7.1 grams d) 6.5 grams e) 2.9 grams

Option (C) is the correct answer.

Explanation:

It is given that partition coefficient between dichloromethane and water is 2.5. Let us assume that "x" grams of caffeine is present in 100 ml.

Hence, find the value of x as follows.

          2.5 =

            x = 25 - 2.5x

           x = 7.14

or,        x = 7.1

Therefore, we can conclude that caffeine extracted is 7.1 grams.

a 20-cm-long, cylindrical graphite (pure carbon) rod is inserted into an oxidizing atmosphere at 1145 k and 1.013 x 105 pa pressure. the oxidizing process is limited by the diffu- sion of oxygen counterflow to the carbon monoxide that is formed on the cylindrical surface.