Distribution coefficient problem for Organic Chem

Click For Summary

Discussion Overview

The discussion revolves around a homework problem regarding the calculation of the distribution coefficient of caffeine between chloroform and water. Participants explore the necessary steps and information required to solve the problem, which involves concepts of concentration and extraction in organic chemistry.

Discussion Character

  • Homework-related
  • Mathematical reasoning

Main Points Raised

  • One participant presents the problem and expresses uncertainty about how to calculate the distribution coefficient.
  • Another participant asks for the initial concentration of caffeine in the aqueous layer before extraction.
  • A different participant inquires about the amount of caffeine remaining in the water after extraction.
  • One participant notes the lack of additional data in the textbook and expresses frustration about the situation.
  • Another participant emphasizes that the concentration must be calculated based on the amount of substance and volume, suggesting a method to approach the problem.

Areas of Agreement / Disagreement

Participants do not reach a consensus on how to proceed with the calculations, and there remains uncertainty regarding the necessary information to solve the problem.

Contextual Notes

The discussion highlights limitations in the provided data, particularly the absence of initial concentration values and other relevant numbers needed for calculations.

orgochem
Messages
2
Reaction score
0

Homework Statement


When 100 mL of an aqueous solution containing 1.0 g of caffeine is extracted with 10 mL of chloroform at room temperature, 0.5 g of caffeine is transferred to the chloroform layer. Calculate the distribution coefficient of caffeine between chloroform and water at room temperature.


Homework Equations



The only thing I have is that Kd=concentration of A in S/ concentration of A in S'
where A= the solute and S/S' are the immiscible solvents

The Attempt at a Solution



I have not a clue how to do this! If someone could walk me through it that would be great! thanks so much!
 
Physics news on Phys.org
What's the concentration of caffeine in the aqueous layer to start with? What about after adding the cloroform?
 
Also: if there is 0.5g in chloroform, how much was left in water?
 
I'm not sure. The book doesn't give any other numbers listed anywhere...thats a state school for ya! The only number that I have for caffeine listed is the 33.3 mg that is in the BC powder that the experiment is done with. I'm sorry! If there is no way to figure this out, its okay, but thanks for your replies!
 
Well of course it's not given, you're supposed to calculate it! Concentration = amt of substance / volume
 

Similar threads

  • · Replies 9 ·
Replies
9
Views
9K
Replies
1
Views
2K
  • · Replies 2 ·
Replies
2
Views
28K
  • · Replies 3 ·
Replies
3
Views
4K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 11 ·
Replies
11
Views
5K
  • · Replies 1 ·
Replies
1
Views
12K
Replies
2
Views
9K
Replies
0
Views
2K
Replies
1
Views
6K