Join TSR now and get all your revision questions answeredSign up now
    Offline

    3
    ReputationRep:
    (Original post by langlitz)
    Sn1 is when the leaving group leaves first then the nucleophile attacks the carbon (Favoured for secondary and tertiary)

    Sn2 is when the nucleophile attacks the central carbon first, there is then a transition state where both the nucleophile and the leaving group are bonded to the carbon. The leaving group then leaves. (Favoured for primary)
    Thank you so much! I've never come across those terms haha..
    Offline

    2
    ReputationRep:
    (Original post by rockinhana)
    i take it back for unit 1 thats insane imagine how a2 edexcel chemistry is.
    ( I do A2 edexcel chemistry lol )
    Yeah Unit 5 isn't very nice..
    Offline

    2
    ReputationRep:
    In your opinion how did last years papers compare to previous years? I'm currently revising for AS and I'm curious.

    Posted from TSR Mobile
    Offline

    3
    ReputationRep:
    Can someone help me with some half equations.

    Like what is the method:

    'When chlorine gas is bubbled into an aqueous solution of sulfur dioxide, hydrogen ions, sulphate ions and chlorine ions are formed'.

    I) Write a half-equation for the formation of chloride ions from chlorine

    Ii) write a half equation for the formation of hydrogen ions and sulfate ions from sulphur dioxide and water.

    Ii) Hence deduce an overall equation for the reaction which occurs when chlorine is bubbled into aqueous sulfur dioxide.

    I) write chlorine is diatomic so I was thinking Cl2+ 2e- --> 2Cl-?

    Ii) not a clue can someone explain these to me thanks
    Offline

    3
    ReputationRep:
    (Original post by zhang-liao)
    I don't know Its just so difficult in the exam sometimes



    Yep, Edexcel Chemistry is harder. I know someone who did AQA Chemistry and she retook different A-Levels and came to the sixth form I'm in and told me that she didn't have to learn half the things we learnt and stuff Like Born Haber cycles.
    They learn Hess' Law and most Organic Chemistry in Unit 2 We learn that stuff in Unit 1
    MCQ is actually hard if you think about it, a lot of students mess up because they panic or because of the way the questions are worded
    Edexcel Physics might be different I guess
    I love Born-Haber and Hess stuff though so I'm not complaining :awesome:
    Unit 1 Organic is easy though, I haven't done any unit 2 paper yet

    Posted from TSR Mobile
    • Welcome Squad
    Offline

    3
    ReputationRep:
    (Original post by C0balt)
    I love Born-Haber and Hess stuff though so I'm not complaining :awesome:
    Unit 1 Organic is easy though, I haven't done any unit 2 paper yet

    Posted from TSR Mobile
    Hess stuff = pure evil :fangs:
    Unit 2 papers have 3 sections to it.
    • Welcome Squad
    Offline

    3
    ReputationRep:
    (Original post by kdizzle97)
    What is SN1 SN2? I do Edexcel Chemistry so this is embarrassing
    Chemrevise is helpful if you don't understand

    (Original post by frozo123)
    Lol actually just looked at an Aqa chemistry paper, edexcel one is much "harder"

    Posted from TSR Mobile
    :sadnod:

    (Original post by rockinhana)
    yeah ur right but why is edexcel harder is the grade boundaries lower
    actually, sometimes the grade boundaries are really high, other times, they're really low. Lowest its ever been is 54 I think out 80 (in Jan 2012) and highest I think was something like 65/80 in the June 2014 paper

    (Original post by rockinhana)
    Yeah i think your notes are cutting edge and as an A2 student that has done AQA there isn't a major difference in the topic. by the way i love nucleophillic addition and mechanisms as a whole
    Thank you Same here, mechanisms are so much more fun than physical chemistry
    Offline

    2
    ReputationRep:
    Posted from TSR Mobile

    Please help!
    Question: Suggest why oxygen radicals are really diradicals.
    Offline

    2
    ReputationRep:
    (Original post by zhang-liao)
    Hess stuff = pure evil :fangs:
    Unit 2 papers have 3 sections to it.
    I personally find Hess' Law related questions God's gift once you understand the principles behind the two cycles.
    Offline

    2
    ReputationRep:
    Posted from TSR Mobile
    Help!
    Stuck on this question 😚😳.
    Attached Images
     
    • Welcome Squad
    Offline

    3
    ReputationRep:
    (Original post by S.Ahmad)
    I personally find Hess' Law related questions God's gift once you understand the principles behind the two cycles.
    I find them horrible

    (Original post by Kadak)
    Posted from TSR Mobile

    Please help!
    Question: Suggest why oxygen radicals are really diradicals.
    Okay, a typical free radical contains ONE unpaired electron. Diradicals woul probably be a species which contains two unpaired electrons. So yeah, you could argue that monoatomic oxygen contains two unpaired electrons
    Offline

    2
    ReputationRep:
    Well firstly work out how many chlorine radicals there are in 1g (using moles and Avogadro's constant). Then divide 150kg by this number to get the mass of ozone destroyed by one radical. Then you can work out how many moles of O3 this is and then multiply by Avogadro's constant.

    Posted from TSR Mobile
    Offline

    3
    ReputationRep:
    (Original post by zhang-liao)
    Hess stuff = pure evil :fangs:
    Unit 2 papers have 3 sections to it.
    I love physical chemistry
    Oh damn, I was planning to do one unit 2 paper today, ended up not doing it lol
    3 sections on organic chem? Nty
    Posted from TSR Mobile
    Offline

    2
    ReputationRep:
    (Original post by C0balt)
    I love physical chemistry
    Oh damn, I was planning to do one unit 2 paper today, ended up not doing it lol
    3 sections on organic chem? Nty
    Posted from TSR Mobile
    Unit 2 isn't just organic for edexcel


    Posted from TSR Mobile
    • Welcome Squad
    Offline

    3
    ReputationRep:
    (Original post by C0balt)
    I love physical chemistry
    Oh damn, I was planning to do one unit 2 paper today, ended up not doing it lol
    3 sections on organic chem? Nty
    Posted from TSR Mobile
    Organic Chemistry is the best :colonhash:

    Noooooo, 3 individual sections so you have Section A (MCQ), Section B (random questions), Section C (a question focussing on a case study or some information - typically Green Chemistry)
    Offline

    3
    ReputationRep:
    (Original post by samb1234)
    Unit 2 isn't just organic for edexcel


    Posted from TSR Mobile
    Well I know, I thought I get three Qs on organic
    I've done extracts of unit 2 paper for test and homework so yeah

    Posted from TSR Mobile
    Offline

    3
    ReputationRep:
    (Original post by zhang-liao)
    Organic Chemistry is the best :colonhash:

    Noooooo, 3 individual sections so you have Section A (MCQ), Section B (random questions), Section C (a question focussing on a case study or some information - typically Green Chemistry)
    Oh ok
    **** green chem...that is the only topic in AS chemistry that I hate with genuine passion

    Posted from TSR Mobile
    • Welcome Squad
    Offline

    3
    ReputationRep:
    (Original post by C0balt)
    Oh ok
    **** green chem...that is the only topic in AS chemistry that I hate with genuine passion

    Posted from TSR Mobile

    Green Chemistry is so boring sometimes
    Offline

    3
    ReputationRep:
    (Original post by zhang-liao)
    Green Chemistry is so boring sometimes
    I mean I get that it is a serious, real issue and we should have an understanding of it.
    But I don't see why I have to be examined one that crap :fuhrer:

    Posted from TSR Mobile
    Offline

    2
    ReputationRep:
    (Original post by samb1234)
    Well firstly work out how many chlorine radicals there are in 1g (using moles and Avogadro's constant). Then divide 150kg by this number to get the mass of ozone destroyed by one radical. Then you can work out how many moles of O3 this is and then multiply by Avogadro's constant.

    Posted from TSR Mobile


    Posted from TSR Mobile

    Thank you 😃 !
 
 
 
Poll
Which web browser do you use?

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

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