Distribution coefficient problem for Organic Chem

In summary, The distribution coefficient of caffeine between chloroform and water at room temperature is 0.5 after extracting 100 mL of an aqueous solution containing 1.0 g of caffeine with 10 mL of chloroform. The concentration of caffeine in the aqueous layer is not given, but can be calculated using the amount of caffeine in BC powder, which is 33.3 mg.
  • #1
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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!
 
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  • #2
What's the concentration of caffeine in the aqueous layer to start with? What about after adding the cloroform?
 
  • #3
Also: if there is 0.5g in chloroform, how much was left in water?
 
  • #4
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!
 
  • #5
Well of course it's not given, you're supposed to calculate it! Concentration = amt of substance / volume
 

1. What is the distribution coefficient problem for Organic Chem?

The distribution coefficient problem for Organic Chem is a phenomenon that occurs when a solute is added to two immiscible solvents. The solute will distribute itself between the two solvents based on the relative solubility in each solvent. This can cause difficulties in accurately measuring the concentration of the solute in either solvent.

2. Why is the distribution coefficient problem important?

The distribution coefficient problem is important because it can affect the accuracy and reliability of experimental results in Organic Chemistry. It can also impact the separation and purification of compounds, which is a crucial aspect of this field of study.

3. How is the distribution coefficient calculated?

The distribution coefficient can be calculated by dividing the concentration of the solute in one solvent by the concentration of the solute in the other solvent. This is known as the partition coefficient, and it is a measure of the solubility of a solute in two different solvents.

4. What factors can affect the distribution coefficient?

The distribution coefficient can be affected by several factors, including the nature of the solute, the properties of the solvents, and the temperature. The polarity, size, and shape of the solute can also play a role in its distribution between the two solvents.

5. How can the distribution coefficient problem be overcome?

The distribution coefficient problem can be overcome by using methods such as liquid-liquid extraction or solid-phase extraction, which take advantage of the differences in solubility and partition coefficients between the solvents. Additionally, adjusting the temperature and choosing appropriate solvents can also help mitigate the effects of this problem.

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