Turn on thread page Beta
    Offline

    0
    ReputationRep:
    Well, there aren't really any big equations you need to know..

    moles = mass / RMM

    moles = (vol * conc.)/1000 (as you're normally given conc.s in moldm-3 and volumes in cm3)

    Relative atomic mass = ((isotope mass * % abundance) + (isotope mass * % abundance)) / ∑%abundances

    That's about it.. at an extreme stretch maybe you would have to know the Avagadro constant is 6.02 * 1023, but I don't think so.
    Offline

    0
    ReputationRep:
    Dus ne1 have ne idea ov wat kinda questions gona *** up..!!!.....??
    Offline

    2
    ReputationRep:
    2NaOH(aq) + H2SO4(aq) ---> Na2SO4(aq) + 2H2O(l)
    so ratio of NaOH : H2SO4 is 2:1
    Offline

    1
    ReputationRep:
    (Original post by k0rrupter)
    sum1 help me out here,

    NaOH(aq) + H2SO4(aq) -----> Na2SO4(aq) + 2H2O(l)

    HOW is the mole ratio of NAOH2SO4 2:1 ?
    You've balanced everything except the sodium hydroxide. You need 2 of them
    Offline

    0
    ReputationRep:
    sh*t, my bad!, cheers!
    Offline

    0
    ReputationRep:
    i thought the equation was:

    NaOH(aq) + H2SO4(aq) -----> NaHSO4(aq) + H2O(l)
    Offline

    13
    (Original post by ram)
    i thought the equation was:

    NaOH(aq) + H2SO4(aq) -----> NaHSO4(aq) + H2O(l)
    .

    yes this is correct also
    Offline

    0
    ReputationRep:
    Has anyone looked at the sample of the new synoptic layout? If not then check it out http://www.edexcel.org.uk/VirtualCon...June_20052.pdf

    Is it just me that finds it really difficult/bordering on impossible? and do you think that the questions tomorrow will be on similar topics?
    Offline

    1
    ReputationRep:
    do u have answers for that paper??

    might print it of and try it lol

    - yeah i guess im gonna have to write tiny to fit it in
    Offline

    14
    ReputationRep:
    (Original post by ram)
    i thought the equation was:

    NaOH(aq) + H2SO4(aq) -----> NaHSO4(aq) + H2O(l)
    in alkaline conditions the sulphuric acid donates both protons to the solution
    Offline

    0
    ReputationRep:
    no, answers aren't on the website, which makes it worse as i can't even see how i should answer the questions
    Offline

    0
    ReputationRep:
    i hv tried doing unit 6 past papers, finding them VERY hard, does anyone know what the grade boundaries are like?
    Offline

    1
    ReputationRep:
    probably 40 / 50 for A?
    Offline

    0
    ReputationRep:
    Jan 05 Unit 6B paper anyone plz?
    Offline

    0
    ReputationRep:
    Ok, on the examiners report for June 03, if you did coursework and synoptic, the raw marks are 82/100 ! But then I guess people who do coursework would just keep doing it again and again until they virtually get 100%. For the practical and synoptic, its 74/100.
    Offline

    2
    ReputationRep:
    (Original post by kpg)
    From the past papers I've done I'd suggest we've gotta be pretty clued up on

    -Calculations...of any kind!
    -Eθ calculations, equations, feasibility etc.
    -All organic reactions
    -All organic mechanisms (though there were 3 in the unit 5)
    -Rates of reactions
    -Equilibria + calculations
    -Shapes of molecules
    -Acid/Base theory
    -Transition metals
    -Extraction of aluminium
    -Intermolecular forces esp. hydrogen bonding and solubility of organic molecules

    Oh and reactions of hydrogen halides with sulphuric acid has come up twice so thats something to keep in mind.
    does ne1 know wot the three mechanisms were in the unit 5 - i didnt do it so i dont know - thanks
    Offline

    0
    ReputationRep:
    Free-radical polymerisation, electrophilic addition of hydrogen bromide to alkene and Sn2 nucleophilic addition of OH- to a halogenoalkane I believe.

    ..What actually is the reaction between hydrogen halides and sulphuric acid?
    Offline

    0
    ReputationRep:
    Hydrogen Halides and CONC Sulphuric Acid

    Chloride - steamy fumes of HCL
    Bromides - steamy fumes of HBr, Br2 and SO2 gas.
    Iodide - Iodine Vapour

    HI is a powerful reducing agent, reduces H2S04 and itself is oxidised to I2
    HBr is just powerful enough to reduce H2S04 to SO2 and its oxidised to Br2
    HCl is a weak reducing agent so doesn't reduce H2S04...
    Offline

    14
    ReputationRep:
    I just did this question from Jun 2001 I think, spent ages on it working out oxidation numbers because Id forogtten it.. thankfully there was a clue it was about oxidation in it
    Offline

    1
    ReputationRep:
    (Original post by Whatsername)
    But then I guess people who do coursework would just keep doing it again and again until they virtually get 100%.
    Very true! I <3 the way you can do that with the coursework!
 
 
 
Turn on thread page Beta
Updated: June 28, 2005
The home of Results and Clearing

3,702

people online now

1,567,000

students helped last year

University open days

  1. Bournemouth University
    Clearing Open Day Undergraduate
    Fri, 17 Aug '18
  2. University of Bolton
    Undergraduate Open Day Undergraduate
    Fri, 17 Aug '18
  3. Bishop Grosseteste University
    All Courses Undergraduate
    Fri, 17 Aug '18
Poll
A-level students - how do you feel about your results?

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.