Hey there! Sign in to join this conversationNew here? Join for free

Edexcel - Chemistry Unit 2 - 4 June 2013 Watch

  • View Poll Results: Which topic(s) are you finding most difficult?
    Shapes of molecules and ions
    11.66%
    Intermediate bonding and bond polarity
    15.95%
    Intermolecular forces
    9.82%
    Redox
    17.79%
    Group 2 & 7
    40.49%
    Kinetics & Equilibria
    14.11%
    Organic Chemistry - Alcohols and Halogenoalkanes
    39.26%
    Mechanisms
    26.38%
    Green Chemistry
    28.83%

    Offline

    2
    ReputationRep:
    (Original post by James A)
    You do get a data booklet, for all chemistry exams.
    Not for AS :/
    • PS Reviewer
    Offline

    20
    ReputationRep:
    PS Reviewer
    (Original post by Gnome :))
    Not for AS :/
    That's odd, I got a data booklet for my AS Chem exams, this was back in June 2011 so I dunno if it's changed since.
    Offline

    16
    ReputationRep:
    (Original post by charlieejobson)
    what section of the syallabus does this come under:

    what colour is the vapour which forms when conc h2so4 is added to solid potassium iodide?
    purple vapour, black solid bad, smell of eggs.
    Offline

    0
    ReputationRep:
    guys why is the angles in cyclohexanol 109.5?
    • PS Reviewer
    Offline

    20
    ReputationRep:
    PS Reviewer
    (Original post by charlieejobson)
    guys why is the angles in cyclohexanol 109.5?
    Tetrahedral = Four bonding pair of electrons = 109.5
    Offline

    0
    ReputationRep:
    (Original post by James A)
    Tetrahedral = Four bonding pair of electrons = 109.5
    i dont see how its four :/
    Offline

    0
    ReputationRep:
    (Original post by James A)
    Tetrahedral = Four bonding pair of electrons = 109.5
    How is it tetrahedral if it's cyclo? :/


    Posted from TSR Mobile
    • PS Reviewer
    Offline

    20
    ReputationRep:
    PS Reviewer
    (Original post by charlieejobson)
    i dont see how its four :/
    Cyclohexanol.

    http://www.chemeddl.org/resources/mo...nol-lewis2.png

    I'm assuming you are referring to the HCH bonds.
    Offline

    0
    ReputationRep:
    (Original post by all_dolled_up)
    How is it tetrahedral if it's cyclo? :/


    Posted from TSR Mobile
    no i understand now, its because there is 2 hydrogens directly attached to each carbon
    Offline

    0
    ReputationRep:
    (Original post by charlieejobson)
    no i understand now, its because there is 2 hydrogens directly attached to each carbon
    Ohh ok, yeah that makes sense now, I'd ignored the hydrogens and just tried to find the c-c bond

    Posted from TSR Mobile
    Offline

    1
    ReputationRep:
    Do we need to memorise the iodate titration equations?
    • Study Helper
    Offline

    2
    ReputationRep:
    Study Helper
    (Original post by Jayqwe)
    Do we need to memorise the iodate titration equations?
    I think you only need to remember the thiosulfate ones, but it would be wise for you to know them.
    • PS Reviewer
    Offline

    20
    ReputationRep:
    PS Reviewer
    Only remember the thiosulfate one. They will give you the other equation, e.g. one involving Potassium Iodide.
    Offline

    0
    ReputationRep:
    Can anyone please explain why the bond angle in hydrogen bonding is 180 degrees.
    • Thread Starter
    Offline

    15
    ReputationRep:
    (Original post by geor)
    If you were titrating acid (in burette) against alkali with the indicator as phenolphthalein; would the colour change be pink to colourless?

    I'm so confused because when I used to do these titrations at my school the end point would always be pale pink, but the mark scheme doesn't seem to accept it..?
    Well according to good old George here, Phenolphthalein is colourless in acid conditions

    so it would go from Colourless to pink, then with excess alkali it will go purple
    • PS Reviewer
    Offline

    20
    ReputationRep:
    PS Reviewer
    (Original post by geor)
    If you were titrating acid (in burette) against alkali with the indicator as phenolphthalein; would the colour change be pink to colourless?

    I'm so confused because when I used to do these titrations at my school the end point would always be pale pink, but the mark scheme doesn't seem to accept it..?
    Maybe because you guys add the base from the burette and the acid is in the conical flask?

    I am 100% sure the end point is colourless.
    • PS Reviewer
    Offline

    20
    ReputationRep:
    PS Reviewer
    (Original post by geor)
    If you were titrating acid (in burette) against alkali with the indicator as phenolphthalein; would the colour change be pink to colourless?

    I'm so confused because when I used to do these titrations at my school the end point would always be pale pink, but the mark scheme doesn't seem to accept it..?
    Remember that in all titrations, you always end up over shooting the end point, so the solution is either more acidic or alkaline, as opposed to being completely neutral.
    • Thread Starter
    Offline

    15
    ReputationRep:
    (Original post by James A)
    Maybe because you guys add the base from the burette and the acid is in the conical flask?

    I am 100% sure the end point is colourless.
    George claims it's "pale pink"

    Might be a mistake, I remember last our year had a dispute over it while we were going into the exam hall I think the CGP says different
    • PS Reviewer
    Offline

    20
    ReputationRep:
    PS Reviewer
    (Original post by posthumus)
    George claims it's "pale pink"

    Might be a mistake, I remember last our year had a dispute over it while we were going into the exam hall I think the CGP says different
    Wiki says that the neutral point is colourless, unless george facer is assuming the titration always overshoots. Honestly don't know.

    I'm just sticking to the end point as pale pink.
    Offline

    1
    ReputationRep:
    anyone know any good definition websites
 
 
 
  • 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.