Chemistry

A student performs a crystallization on an impure sample of biphenyl. The sample weighs 0.5 g and contains about 5% impurity. Based on his knowledge of solubility the student decides to use benzene as the solvent. After crystallization, the crystals are dried and the final weight is found to be 0.02 g. Assume that all the steps in the crystallization are performed correctly, there are no spills, and the student lost very littly solid on any glassware or in any of the transfers. Why is the recovery so low?

thanks so much in advance!

  1. 👍 0
  2. 👎 0
  3. 👁 527
asked by Nina
  1. How soluble is biphenyl is benzene? Perhaps it is just too soluble, and/or there is not enough difference in solubility at low temp and high temp.

    1. 👍 0
    2. 👎 0
    posted by DrBob222
  2. I had this same question in my last lab. The reason this occurs is due to the solubility of biphenyl and benzene. There is not much difference between room temp and boiling so not much is going to crystallize out. Benzene is too good of a solvent for biphenyl and shouldn't be used for re-crystallization.

    1. 👍 0
    2. 👎 0

Respond to this Question

First Name

Your Response

Similar Questions

  1. Organic Chemistry

    A student performs a crystallization on an impure sample of biphenyl. The sample weighs 0.5 g and contains about 5% impurity. Based on his knowledge of solubility, the student decides to use benzene as the solvent. After

    asked by Lily Walker on September 5, 2018
  2. Low recovery

    The question is: A student performs a crystallization on an impure sample of biphenyl. The sample weighs 0.5g and contains about 5% impurity. Using his knowledge of solubility, he decides to use benzene as a solvent. The final

    asked by Sheryl on September 26, 2006
  3. Chemistry

    A sodium hydroxide sample is contaminated with sodium chloride. A 0.240 gram sample of this impure sample is dissolved in water and titrated with 21.50 mL of 0.130 M H2C2O4. Calculate the percent sadium hydroxide in the impure

    asked by Sam on July 15, 2015
  4. Science

    So a crystallization experiment was performed using an impure sample of biphenly, it weights 0.5g and contains about 5% impurity. Benzene is used as the solvent but after crystallization only about 0.02g were found. If everything

    asked by Dre on June 6, 2007
  5. chemistry

    CrCl3(s) + AgNO3 (aq)= AgCl(s) + Cr(NO3)3(aq) A 0.750 g sample of impure CrCl3 was removed from a bottle that contained 1.75 g of impure sample. The removed sample was dissolved in water and required 42.5 mL of 0.215 M AgNO3

    asked by jade on March 12, 2012
  6. Chemistry

    A student was given a 2.45 g of impure potassium sulfate (K2SO4) sample. He dissolved this sample in 100 mL of water first and then added some barium chloride (BaCl2) solution. A 2.15 g of BaSO4 precipitate was obtained at the end

    asked by Anonymous on November 22, 2014
  7. Chemistry

    An impure sample containing an unknown amount of gallium bromide, GaBr3, weighs 0.379 g. It was dissolved in water and treated with silver nitrate, AgNO3, resulting in the precipitation of 0.263 g AgBr. Assuming that GaBr3 is the

    asked by Hannah on November 1, 2017
  8. College Chem

    Impure sample of table salt that weighed 0.8421g, when dissolved in water and treated with excess AgNO3, formed 2.044g of AgCl. What is the percentage of NaCl in the impure sample? Do I need the molecular weight to start this

    asked by London on March 17, 2010
  9. chemistry

    consider a crystallization of sulfanilamide in which 10 mL of hot 95% ethyl alcohol is added to 0.10 g of impure sulfanimide. after the solid has dissolved, the solution is cooled to room temp. and then placed into an ice-water

    asked by BOB on October 7, 2008
  10. Melting point

    Could you tell me what the melting point for a crystallized sulfanamide is? Also, we will have to determine the m.p. of an impure sulfanamide. Any idea of a temperature range for that? Will it be higher of lower? Probably hard to

    asked by Sheryl on September 26, 2006

More Similar Questions