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

    1
    ReputationRep:
    What did you get when comparing the melting points, after the drawing the hydrogen bonding diagram part, was it to do with one having hydrogen bonding and the other not? :/
    Offline

    1
    ReputationRep:
    (Original post by Lil670)
    What did you get when comparing the melting points, after the drawing the hydrogen bonding diagram part, was it to do with one having hydrogen bonding and the other not? :/
    That's what I put, just a hopeful guess
    Offline

    3
    ReputationRep:
    (Original post by robinback)
    That's what I put, just a hopeful guess
    Both of them could hydrogen bond...


    Posted from TSR Mobile
    Offline

    3
    ReputationRep:
    (Original post by RasputinReborn)
    Both of them could hydrogen bond, they both had a NH2 group but the other one has an OH group


    Posted from TSR Mobile



    Posted from TSR Mobile
    Offline

    10
    ReputationRep:
    (Original post by RasputinReborn)
    Both of them could hydrogen bond...


    Posted from TSR Mobile
    Yeah they could bith hydrogen bond. One had NH3 and the other had an OH and I said the OH had a more electronegative O therefore the electronegativity difference In the hydrogen bond was greater therefore the strength of the bond would increase. In addition, one ofthe molecules was slightly larger than the other so there was a greater surface area for contact between molecules therefore there could be induced diploe induced dipole interactions. Kinda waffled a load of stuff I know about bonding tbh...
    Offline

    5
    ReputationRep:
    That exam is a blur to me now. Do you think the boundaries will be lowered? whats the usual grade boundaries? and did anyone do biology yesterday?
    Offline

    3
    ReputationRep:
    (Original post by ambarellarose)
    That exam is a blur to me now. Do you think the boundaries will be lowered? whats the usual grade boundaries? and did anyone do biology yesterday?
    They definitely will be lowered because this exam was harder than all those on the previous spec and because no Y13s could resit and inflate the boundaries.

    Usual grade boundaries are roughly:

    A - 73%

    B- 68%

    C- 62%

    D- 57%

    E- 52%

    U <52%

    These are raw percentages made as a mean from previous exam boundaries .






    Posted from TSR Mobile
    Offline

    0
    ReputationRep:
    I got x=2 but let's just say overall that paper was hell!!!
    Offline

    1
    ReputationRep:
    (Original post by ambarellarose)
    That exam is a blur to me now. Do you think the boundaries will be lowered? whats the usual grade boundaries? and did anyone do biology yesterday?
    Good to see you on this thread too haha
    Offline

    0
    ReputationRep:
    What did u guys get for atom economy? I got 77.0%
    Offline

    0
    ReputationRep:
    (Original post by Emskibump)
    I got 2, what did you get?
    Posted from TSR Mobile
    I got X=2 and so did most people
    Offline

    0
    ReputationRep:
    What was with the electrolysis question, wasn't even on the spec...
    Offline

    10
    ReputationRep:
    (Original post by Chemistrycat98)
    What was with the electrolysis question, wasn't even on the spec...
    It was on the spec, iodide ions gain electrons forming iodine which turns to a red/brown solution. Then you'd explain why- basically liberation of Iodine but I cba to explain now.. Go on chemguide and it'll explain probably.
    Offline

    0
    ReputationRep:
    (Original post by Elliottmanwaring)
    It was on the spec, iodide ions gain electrons forming iodine which turns to a red/brown solution. Then you'd explain why- basically liberation of Iodine but I cba to explain now.. Go on chemguide and it'll explain probably.

    Seems like you knew your stuff for that **** exam I'm dreading results day for CH1
    Offline

    10
    ReputationRep:
    Cheers buddy! Just to give you the info- https://answers.yahoo.com/question/i...9033546AARgz93 thats a link... 4th paragraph contains basically the reasoning behind what is happening in the electrolysis.
    (Original post by ChemSinceDaay...)
    Seems like you knew your stuff for that **** exam I'm dreading results day for CH1
    Offline

    3
    ReputationRep:
    (Original post by Elliottmanwaring)
    Cheers buddy! Just to give you the info- https://answers.yahoo.com/question/i...9033546AARgz93 thats a link... 4th paragraph contains basically the reasoning behind what is happening in the electrolysis.
    Aren't iodide ions oxidised to form I2, because if they gain electrons, they'll form I2- ions.
    Offline

    10
    ReputationRep:
    (Original post by RasputinReborn)
    Aren't iodide ions oxidised to form I2, because if they gain electrons, they'll form I2- ions.
    That statement is partially correct. It is true that the iodide is oxidised therefore loses an electron to form a neutral, diatomic iodine molecule. The fact that they would otherwise form I2- is incorrect. They could possibly form I3- but not I2-. I'm no Chemist so don't ask why I just remember reading that the for mation of a dinegative iodide isn't apparent. Only a trinegative ion called.. Imaginatively as all scientists are.... Triiodide. It is actually a combination of three Iodine atoms. But yeah in answer to your question, I don't think you can get an I2- because if you were to do that you'd be adding an electron to the 6s sub-shell. The addition of 1 do an iodine atom forms just I-.
    Offline

    0
    ReputationRep:
    (Original post by Elliottmanwaring)
    It was on the spec, iodide ions gain electrons forming iodine which turns to a red/brown solution. Then you'd explain why- basically liberation of Iodine but I cba to explain now.. Go on chemguide and it'll explain probably.
    Isn't iodine insoluble? Isn't it bromine that would turn the solution a red/brown color? I said a grey solid would form on the anode.
    Offline

    3
    ReputationRep:
    (Original post by Elliottmanwaring)
    That statement is partially correct. It is true that the iodide is oxidised therefore loses an electron to form a neutral, diatomic iodine molecule. The fact that they would otherwise form I2- is incorrect. They could possibly form I3- but not I2-. I'm no Chemist so don't ask why I just remember reading that the for mation of a dinegative iodide isn't apparent. Only a trinegative ion called.. Imaginatively as all scientists are.... Triiodide. It is actually a combination of three Iodine atoms. But yeah in answer to your question, I don't think you can get an I2- because if you were to do that you'd be adding an electron to the 6s sub-shell. The addition of 1 do an iodine atom forms just I-.
    But for the sake of the exam, were the marks for:

    2I- -----> I2 +2e- (1)

    Solution turns brown (1)

    Don't know what the third mark is, but j said chlorine has a higher electron affinity so displaces iodine and stays in solution



    Posted from TSR Mobile
    Offline

    10
    ReputationRep:
    (Original post by RasputinReborn)
    But for the sake of the exam, were the marks for:

    2I- -----> I2 +2e- (1)

    Solution turns brown (1)

    Don't know what the third mark is, but j said chlorine has a higher electron affinity so displaces iodine and stays in solution



    Posted from TSR Mobile
    As I said, I'm no pro but I would assume the marks are for:
    1. Chlorine is a more powerful oxidising agent than Iodine so it liberates the iodine.
    2. 2I- ---> I2 + 2e-
    3. Solution turns dark red/brown colour and an explanation of basically what the equation is telling you in terms of movement of electrons.

    That's what I put but I'm not sure if that is on the mark scheme.
 
 
 
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.