Hey there! Sign in to join this conversationNew here? Join for free
    • Thread Starter
    Offline

    2
    ReputationRep:
    Why recrystallization works on the basis that cooled solution is saturated with the desired material but not with the impurities?

    Cuz I thought it is the desired material got crystallized, not the impurities?

    Did I misunderstand something?

    Thanks for any replies in advance
    Offline

    1
    ReputationRep:
    when you wash it through with a solvent, the desired product stays and the impurities dissolve with and you end up with the crystals and a bunch of solvent with the impurities dissolved in it.
    Offline

    19
    ReputationRep:
    (Original post by MrFartFace)
    when you wash it through with a solvent, the desired product stays and the impurities dissolve with and you end up with the crystals and a bunch of solvent with the impurities dissolved in it.
    This thread is about recrystallisation, not washing on a filter...
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by MrFartFace)
    when you wash it through with a solvent, the desired product stays and the impurities dissolve with and you end up with the crystals and a bunch of solvent with the impurities dissolved in it.
    Then the solvent is saturated with impurities isn't it?
    Offline

    1
    ReputationRep:
    (Original post by mystreet091234)
    Then the solvent is saturated with impurities isn't it?
    The solvent has all the impurities dissolved in it, the crystals shouldn't dissolve in the solvent, they stay in the funnel.
    Offline

    19
    ReputationRep:
    (Original post by MrFartFace)
    The solvent has all the impurities dissolved in it, the crystals shouldn't dissolve in the solvent, they stay in the funnel.
    Have you ever done a recrystallisation? What you have said is completely wrong.
    Offline

    1
    ReputationRep:
    Yeah I did the PSA in it earlier this year.
    Offline

    19
    ReputationRep:
    (Original post by MrFartFace)
    Yeah I did the PSA in it earlier this year.
    Then you did it wrong. In a recryst you dissolve the crude product, filter out any insoluble impurities and cool the filtered solution to get your purified product, followed by drying.
    Offline

    1
    ReputationRep:
    (Original post by alow)
    Then you did it wrong. In a recryst you dissolve the crude product, filter out any insoluble impurities and cool the filtered solution to get your purified product, followed by drying.
    Cheers for clearing that up.
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by MrFartFace)
    The solvent has all the impurities dissolved in it, the crystals shouldn't dissolve in the solvent, they stay in the funnel.
    Actually this is the question I was talking about.

    I think D is weird as the solution should be saturated with soluble impurities, though I know ABC must be wrong.
    Attached Images
     
    Offline

    1
    ReputationRep:
    It's D, when you cool it, the purer product is formed, but the impurities stay mostly dissolved
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by MrFartFace)
    It's D
    Yea I know
    But why?
 
 
 
Poll
Do you agree with the PM's proposal to cut tuition fees for some courses?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.