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    (Original post by 12284)
    No you don't need to include it.
    And yep it is on the spec but I haven't seen a question on it yet.
    What do we need to know about the M+1 peak?
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    (Original post by Kaya22)
    if you divide by the volumes you get the wrong ph
    well i got the correct answer when dividing by the new total volume 1.005dm-3
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    (Original post by Guls)
    Na2CO3 + HCl → NaCl + NaHCO3
    NaHCO3 + HCl → NaCl + H2O + CO2
    The conjugate acid produced from the first equation is so weak that it can accept another proton to form NaCl creating two concentrations of where the [OH]=[H+]
    I think I kind of get that

    But then how this gets the moles of ethanediocacid I don't know
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    (Original post by dingdon)
    how did you know where double bond goes?
    it will go to where there is a hydrogen on the adjacent carbon to C-OH. Hard to explain. I'll draw a quick diagram hold on
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    (Original post by Sniperdon227)
    well i got the correct answer when dividing by the new total volume 1.005dm-3
    my calculator played up like 5 times ahaha i knew exactly what i was doing but my i hope my calculator doesnt do that in the exam!
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    (Original post by dingdon)
    how did you know where double bond goes?
    well it cant be c-c-c=cooh because the 1st carbon counting from the c in cooh would have 5 bonds so it can only be c-c=c-cooh
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    For questions that ask for equations, particularly fragmentation equations, I always end up drawing out the compound (instead of writing CH3CH2CH2 etc.) will I lose marks?????????
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    (Original post by dingdon)
    how did you know where double bond goes?


    The arrow from the OH bond is where the double dond would be. In other compunds there could be multiple places the double could go which leads to isomers
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    (Original post by dingdon)
    how did you know where double bond goes?
    draw out both scenarios and you'll see
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    (Original post by lahigueraxxx)
    For questions that ask for equations, particularly fragmentation equations, I always end up drawing out the compound (instead of writing CH3CH2CH2 etc.) will I lose marks?????????
    No
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    (Original post by SirRaza97)
    No
    phew, thank you!
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    (Original post by lahigueraxxx)
    phew, thank you!
    Sometimes they specifically want a displayed formula as well so it's safe to do so. Unless they speficially ask for the structural formula then you should be ay-okay
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    (Original post by lahigueraxxx)
    For questions that ask for equations, particularly fragmentation equations, I always end up drawing out the compound (instead of writing CH3CH2CH2 etc.) will I lose marks?????????
    they are never clear what they want, whether that be the structural formula or displayed, so i think both are accepted
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    (Original post by Sniperdon227)
    they are never clear what they want, whether that be the structural formula or displaced, so i think both are accepted
    awesome, thank you! No they are never clear but it would be really annoying to get marked down on something like that
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    (Original post by SirRaza97)
    Sometimes they specifically want a displayed formula as well so it's safe to do so. Unless they speficially ask for the structural formula then you should be ay-okay
    Will keep that in mind - thanks again!
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    http://filestore.aqa.org.uk/subjects...4-QP-JUN12.PDF

    4fii it asks about indicators' colour change, without telling us any detail about its colour in acid or alkali, are we supposed to memorise that?
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    What are the predictions for this year?
    I don't understand what they could ask about gas chromatography? Any guesses
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    (Original post by Seclusion)
    http://filestore.aqa.org.uk/subjects...4-QP-JUN12.PDF

    4fii it asks about indicators' colour change, without telling us any detail about its colour in acid or alkali, are we supposed to memorise that?
    Supposed to know the Phenolpthalein and Methyl Orange colour changes.
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    (Original post by Seclusion)
    http://filestore.aqa.org.uk/subjects...4-QP-JUN12.PDF

    4fii it asks about indicators' colour change, without telling us any detail about its colour in acid or alkali, are we supposed to memorise that?
    you should know the colours of phenopthalein and methyl orange in acid and alkali
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    (Original post by Parallex)
    Supposed to know the Phenolpthalein and Methyl Orange colour changes.
    (Original post by Sniperdon227)
    you should know the colours of phenopthalein and methyl orange in acid and alkali
    Ah! Thank you. It's just that I don't see it on the spec? Maybe I am missing it?
 
 
 
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