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    (Original post by cowie)
    most +ve electrode potential means it's the best oxidising agent (itself is reduced).. Like I'm certain there..
    One oxidises the other due to which is the higher electrode potential. More +ve electrode potential is reduced and oxidises the one with the lower electrode potential.
    The reaction happens if the total electrode potential (more +ve - more -ve) is positive.



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    My bad, I literally slipped right there LOL xD Yup, you are correct
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    For any calculation questions do you have to show the full working out that they used? Sometimes I'll show like a line or two and I'll get the answer right but would they give full marks for that even though I'd show every line that they've mentioned in the mark scheme?
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    Why is a ammonia a stronger ligand in comparison to water?


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    (Original post by Lilly1234567890)
    Why is a ammonia a stronger ligand in comparison to water?


    Posted from TSR Mobile

    Well, a ligand is a lewis base (electron donor). So i think that ammonia is a more basic than water (in terms of pH), and so it will be stronger as a ligand.
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    (Original post by theboss1998)
    Well, a ligand is a lewis base (electron donor). So i think that ammonia is a more basic than water (in terms of pH), and so it will be stronger as a ligand.
    You're not really answering the question. Why is it more basic? The more basic it is, the stronger the ligand so to answer the latter requires full explanation of the former.

    (Original post by Lilly1234567890)
    Why is a ammonia a stronger ligand in comparison to water?
    Ligands are electron pair donors
    If you can donate the lone pair of electrons to the metal ion more readily, you are going to form a stronger coordinate bond.
    Nitrogen is less electronegative than oxygen so the lone pair of electrons is electrostatically attracted less to the nucleus. Thus it is more available to be accepted.


    If I blu-tacced some money to a wall and superglued the same amount of money to another wall, which one is more obtainable? Same principle.

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    (Original post by RMNDK)
    You're not really answering the question. Why is it more basic? The more basic it is, the stronger the ligand so to answer the latter requires full explanation of the former.



    Ligands are electron pair donors
    If you can donate the lone pair of electrons to the metal ion more readily, you are going to form a stronger coordinate bond.
    Nitrogen is less electronegative than oxygen so the lone pair of electrons is electrostatically attracted less to the nucleus. Thus it is more available to be accepted.


    If I blu-tacced some money to a wall and superglued the same amount of money to another wall, which one is more obtainable? Same principle.

    Posted from TSR Mobile
    I think ammonia is more polar than water as ammonia is NH3 and is trigonal pyramidal so it is more polar due to it having 3 inductive effects due to 3xH, than H2O which only has 2 inductive effects due to only 2xH?
    And hence its electrons are more available as it is more polar?
    - I may be wrong


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    (Original post by theboss1998)
    Well, a ligand is a lewis base (electron donor). So i think that ammonia is a more basic than water (in terms of pH), and so it will be stronger as a ligand.
    its electron pair donor.
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    For the nucleophilic addition reaction of aldehydes and ketones with HCN, does it need a dilute HCl catalyst? Also it it better to use KCN/NaCN since HCN is more toxic?
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    is the rate equation and the rate expression the same thing?
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    Does one ethyl group have the same positive inductive effect as two methyl groups ? I can't find an answer
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    (Original post by cowie)
    I think ammonia is more polar than water as ammonia is NH3 and is trigonal pyramidal so it is more polar due to it having 3 inductive effects due to 3xH, than H2O which only has 2 inductive effects due to only 2xH?
    And hence its electrons are more available as it is more polar?
    - I may be wrong


    Posted from TSR Mobile
    I don't think NH3 is more polar as the N-H bond will have a smaller dipole moment than the O-H bond. I'm also not so sure whether you can talk about hydrogen creating positive inductive effects, but even so, you can't compare as the central atom is different.
    Yes there are more hydrogen atoms which release electrons, but oxygen will pull the electron density of the hydrogen atoms even more than nitrogen, and I don't know which is the bigger factor.
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    does a catalyst affect the rate constant?
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    (Original post by Superbubbles)
    does a catalyst affect the rate constant?
    No, only temperature will affect it
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    does anyone know why in the condensation reaction 2n-1 water is produced
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    Anyone know the acid dissociation of H3PO4? - or what aqa want us to believe it is at least?


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    (Original post by shiney101)
    No, only temperature will affect it
    You are wrong. you are thinking of Kc.
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    (Original post by JacobFinney)
    If anyone can be arsed...Is it possible to run me through why there is a 3:5 ratio of manganate(VII): Iron(II) ethanedioate as opposed to the 2:5 ratio that I managed to get after cancelling out the electrons etc on June 2012 6(d)(i) ? I managed to get 4/5 for working through with my ratio but am a bit irritated at not being able to work out the right ratio.
    http://filestore.aqa.org.uk/subjects...5-QP-JUN12.PDF
    Ta
    Iron ethanedioate releases 3 electrons. managnate releases 5.
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    (Original post by cowie)
    anyone know the acid dissociation of h3po4? - or what aqa want us to believe it is at least?


    posted from tsr mobile
    h3po4 -----> h2po4- + h+
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    (Original post by JK11)
    You are wrong. you are thinking of Kc.
    Ahh yes! My bad, thanks for correcting me.
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    I don't really understand the difference in buffer calculation when there is XS base or XS acid?
    What I usually do:
    1. Find moles of each acid/base given
    2. Find the XS mol of whatever is in XS
    Am I right in thinking you use Ka for the acid XS buffer?
    I always get the final answer wrong (
 
 
 
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