Hey there! Sign in to join this conversationNew here? Join for free
x Turn on thread page Beta
    Offline

    12
    ReputationRep:
    (Original post by thad33)
    If you go onto YouTube there's a chemistry teacher that goes through last years papers


    Posted from TSR Mobile
    Thanks!


    Posted from TSR Mobile
    Offline

    3
    ReputationRep:
    (Original post by ranz)
    thankkkk you soo much! for ocr A am i right?


    Posted from TSR Mobile
    Yes


    Posted from TSR Mobile
    Offline

    1
    ReputationRep:
    Hi, just wondering, F321, I can't remember, can they actually test us on 'the changing atom'? OCR A, Thanks!
    Offline

    16
    ReputationRep:
    (Original post by liam8195)
    Hi, just wondering, F321, I can't remember, can they actually test us on 'the changing atom'? OCR A, Thanks!
    No it's not in the spec

    Posted from TSR Mobile
    Offline

    2
    ReputationRep:
    Hey, does anyone know papers from other exam boards are most similar to F324? I'm pretty worried about F324 and struggling with timing so I want to do more timed papers but I don't really want to run out of OCR ones because even now I keep on remembering answers to questions taken from OCR papers we've done in class so I'm worried my marks aren't gonna be representative if I've seen the questions before? Or if there's anywhere to get organic questions online that would also be really helpful. If anyone has any advice that would be fab thank you

    Posted from TSR Mobile
    Offline

    1
    ReputationRep:
    (Original post by LThomas694)
    Hey, does anyone know papers from other exam boards are most similar to F324? I'm pretty worried about F324 and struggling with timing so I want to do more timed papers but I don't really want to run out of OCR ones because even now I keep on remembering answers to questions taken from OCR papers we've done in class so I'm worried my marks aren't gonna be representative if I've seen the questions before? Or if there's anywhere to get organic questions online that would also be really helpful. If anyone has any advice that would be fab thank you

    Posted from TSR Mobile
    OCR '2815' papers are always good, legacy papers too.
    Type in 2815 ocr chemistry you should find some
    Offline

    2
    ReputationRep:
    (Original post by liam8195)
    OCR '2815' papers are always good, legacy papers too.
    Type in 2815 ocr chemistry you should find some
    Okay that's great, thank you!
    Offline

    10
    ReputationRep:
    Any tips for redox titration questions/buffers/nmr(hard questions)/electrode potentials/synthesis? These seem to be my weakest areas and they also carry the most amount of marks >.< Would be awesome to nail these. Any tips on nailing them or any super hard questions on these topics would be appreciated!
    Offline

    4
    ReputationRep:
    Why do buffers need excess weak acid? Is it so the equilibrium stays to the right and we have conjugate base ions? But then why aren't they enough from the salt?


    Posted from TSR Mobile
    Offline

    3
    ReputationRep:
    (Original post by Saywhatyoumean)
    Why do buffers need excess weak acid? Is it so the equilibrium stays to the right and we have conjugate base ions? But then why aren't they enough from the salt?


    Posted from TSR Mobile
    we need enough weak acid so we can have plenty to react with any alkali added causing the equilibrium to shift to the right. there arent enough conjugate base ions because the avid is weak so therefore doesnt fully dissociate,


    Posted from TSR Mobile
    Offline

    3
    ReputationRep:
    (Original post by chanda01)
    Any tips for redox titration questions/buffers/nmr(hard questions)/electrode potentials/synthesis? These seem to be my weakest areas and they also carry the most amount of marks >.< Would be awesome to nail these. Any tips on nailing them or any super hard questions on these topics would be appreciated!
    study the mark scheme for buffer solutions, its literally repeated every single time! try to understand it for redox i dont know myself im struggling big time with it lol


    Posted from TSR Mobile
    • Political Ambassador
    Offline

    16
    ReputationRep:
    Political Ambassador
    Anyone have the 2015 F332-F335 papers with the MS OCR B salters still havent posted -.- ??
    Offline

    4
    ReputationRep:
    (Original post by ranz)
    we need enough weak acid so we can have plenty to react with any alkali added causing the equilibrium to shift to the right. there arent enough conjugate base ions because the avid is weak so therefore doesnt fully dissociate,


    Posted from TSR Mobile
    Thanks!
    Offline

    12
    ReputationRep:
    Omg can someone go over equilibrium I don't understand it at all. I understand the principles but the questions f me up 🙄🙄🙄


    Posted from TSR Mobile
    Offline

    2
    ReputationRep:
    (Original post by Saywhatyoumean)
    Why do buffers need excess weak acid? Is it so the equilibrium stays to the right and we have conjugate base ions? But then why aren't they enough from the salt?


    Posted from TSR Mobile
    It's less about being in excess compared to it's conjugate base because buffer's work best when the conc. of weak acid is equal to the conc. of it's conjugate base. It needs to be in overall excess because any strong acid or base (like NaOH) added will dissociate completely and will require a lot of the buffer to remove it.
    Remember buffers can only resist small changes of pH. Only a small amount of strong acids or bases need to be added to change the pH significantly. So it would make sense that a lot of the weak acid is needed in the buffer to remain effective for a long period.
    The conjugate base comes from the complete dissociation of the salt, you are right.
    Offline

    1
    ReputationRep:
    does someone have a working link to the f321 answers (the one next to the definitions)
    Offline

    2
    ReputationRep:
    (Original post by liam8195)
    OCR '2815' papers are always good, legacy papers too.
    Type in 2815 ocr chemistry you should find some
    Aren't OCR 2815 the legacy papers? The A2 equivalent exams of the old legacy spec have the code 2815
    Offline

    2
    ReputationRep:
    Can someone help settle something? Transition metals form coloured compounds because of the splitting of the d-shell and it being incomplete meaning the electrons can jump between levels and emit light. So why can Manganese produce a deep purple colour at oxidation 7+ where it has no electrons in the d sub shell?

    Actually, looking at the table there a few that do the same. Titanium even has a 5+ oxidation state. That would mean dropping into the 3p sub shell...
    Offline

    15
    ReputationRep:
    Do I still have a chance of an A* overall if I got an A at AS but a low B in my A2 practicals but I get an A* in the exams?
    Offline

    2
    ReputationRep:
    (Original post by tcameron)
    Do I still have a chance of an A* overall if I got an A at AS but a low B in my A2 practicals but I get an A* in the exams?
    Yes, if you had the lowest B possible then you'd need 95% in the exams
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: March 4, 2018
Poll
Do you like carrot cake?

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.