Chemistry

posted by .

I'm supposed to do this for an organic chemistry prelab. I've read my books and tried Googling everything possible, but I still don't know how to set this up. Please help!

The solubility of a certain compound in ice-cold water is 0.18g in 100 mL. Its solubility in hot water is 2.35g in 100 mL. What is the best possible percent recovery we can expect for recrystallization of this compound from water?

  • Chemistry -

    You don't have enough information posted to work the problem. Here is what you do.
    Look at your procedure and calculate the grams of product you expect to make assuming 100% for the reaction. Then multiply 0.18 x (volume you expect/100) and subtract from the product you expect to have. Finally, the amount left/amount expectedt)*100 = maximum recovery you can expect. You won't get that because the reaction won't be 100%. The idea is that if the solubility is 0.18 g/100 mL, you will lose that much per 100 mL during recrystallization (if just one recryst is done). If you expect to recrystallize more than once, you will lose that much each time.

  • Chemistry -

    I've had second thoughts about this. Although I think my initial response is correct, I believe we can approach it another way much simpler.
    If we take a 2.35g sample, we can dissolve it in 100 mL water. If we then crystallize it at ice cold temperature, 0.18g of it will be lost. So the amount recovered is 2.35-0.18 =2.17g
    %recovery = (2.17/2.35)*100 = x or about 92%

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Organic Chemistry

    The solubility of a compound is 59g per 100mL in boiling methanol and 30g per 100mL in cold methanol, whereas its solubility in water is 7.2g per 100mL at 95C and 0.22g per 100mL at 2C. Which solvent would be better for recrystallization …
  2. organic chemistry

    The solubility of a compound is 59g per 100mL in boiling methanol and 30g per 100mL in cold methanol, whereas its solubility in water is 7.2g per at 95 degrees Celsius and 0.22g per 100mL at 2 degrees Celsius. Which solvent would be …
  3. organic Chemistry

    In my Organic chemistry lab, the calculated enantiomeric excess was over 100% . Is this possible?
  4. Chemistry

    I have to write the exact lewis electron dot structure for para xylene C8H10. I tried writing it out but it doesnt work out proerly. C is supposed to have 31 electrons and H is supposed to have 10 totaling 42. i was doing research …
  5. Organic Chemistry

    Which statements are FALSE about selecting a solvent for recrystallization?
  6. Organic Chemistry

    A compound whose solubility in ethanol is 4.24g/100ml at 78c and .3 g/100ml at 0c is recrystalize by heating it at 78 and then cooling it to 0c. If we are to recrystalize a .5g of this compound in a 10ml of solvent, what is the maximum …
  7. Chemistry

    The solubility of a certain compound in ice-cold water is 0.22g in 100mL. Its solubility in hot water is 4.35g in 100mL What is the best possible percent recovery we can expect for the re-crystallization of this compound in water?
  8. Chemistry

    A dilute aqueous solution of an organic compound soluble in water is formed by dissolving 2.35 g of the compound in water to form 0.250 L solution. The resulting solution has an osmotic pressure of 0.605 atm at 25 Celsius. Assuming …
  9. chemistry

    The solubility of a compound in water is 6.8g/100ml at 25°C. Calculate the amount of water required to crystallise 10g of the compound. If the pure compound is collected at 25°C what is the maximum possible yield percent?
  10. Organic Chemistry

    Compound A has solubility at 20 degrees celsius of .029 g / 10.0 mL. How much of compound A will remain in solution after cooling to 20 degrees C?

More Similar Questions