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

    2
    ReputationRep:
    I have a couple of questions I'm stuck on about aspirin. Any help appreciated.

    During the making of aspirin, is an ester the functional group created?

    Also, I've been told to work out a theoretical yield of aspirin, using 3g of hydroxybenzoic acid, and4ml of ethanouc anhydride, so need to work out the moles. What is the usual concentration of ethanouc anhydride used for this experiment?

    Also, why is water added to the mixture after reflux, and what is the purpose of cooling using an ice bath? Does it help with crystallisation?

    Thanks for any help
    Offline

    18
    ReputationRep:
    (Original post by definite_maybe)
    I have a couple of questions I'm stuck on about aspirin. Any help appreciated.

    During the making of aspirin, is an ester the functional group created?
    Yes

    Also, I've been told to work out a theoretical yield of aspirin, using 3g of hydroxybenzoic acid, and4ml of ethanouc anhydride, so need to work out the moles. What is the usual concentration of ethanouc anhydride used for this experiment?
    Pure ethanoic anhydride, not a solution, you may want the density of the liquid.

    Also, why is water added to the mixture after reflux, and what is the purpose of cooling using an ice bath? Does it help with crystallisation?
    The water is added to separate the organic and inorganic components of the crude mixture.

    An ice bath is used to decrease the solubility of the desired product from the crystallisation solvent (higher temperatures = more soluble, lower temperatures = less soluble).
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by EierVonSatan)
    Yes



    Pure ethanoic anhydride, not a solution, you may want the density of the liquid.



    The water is added to separate the organic and inorganic components of the crude mixture.

    An ice bath is used to decrease the solubility of the desired product from the crystallisation solvent (higher temperatures = more soluble, lower temperatures = less soluble).
    Thank you. I haven't been given the density of the liquid to work out the theoretical yield. If the density is 1.08 (from wiki :p:) , is the mass then 1.08*4, and then use this to work out moles?
    Offline

    18
    ReputationRep:
    (Original post by definite_maybe)
    Thank you. I haven't been given the density of the liquid to work out the theoretical yield. If the density is 1.08 (from wiki :p:) , is the mass then 1.08*4, and then use this to work out moles?
    Yep (the density is correct)
 
 
 
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • Poll
    Would you rather give up salt or pepper?
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • 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.