Complete Question
A student is extracting caffeine from water with dichloromethane. The K value is 4.6. If the student starts with a total of 40 mg of caffeine in 2 mL of water and extracts once with 6 mL of dichloromethane
The experiment above is repeated, but instead of extracting once with 6 mL the extraction is done three times with 2 mL of dichloromethane each time. How much caffeine will be in each dichloromethane extract?
Answer:
The mass of caffeine extracted is [tex]P = 39.8 \ mg[/tex]
Explanation:
From the question above we are told that
The K value is [tex]K = 4.6[/tex]
The mass of the caffeine is [tex]m = 40 mg[/tex]
The volume of water is [tex]V = 2 mL[/tex]
The volume of caffeine is [tex]v_c = 2 mL[/tex]
The number of times the extraction was done is n = 3
Generally the mass of caffeine that will be extracted is
[tex]P = m * [\frac{V}{K * v_c + V} ]^3[/tex]
substituting values
[tex]P = 40 * [\frac{2}{4.6 * 2 + 2} ]^3[/tex]
[tex]P = 39.8 \ mg[/tex]
