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    (Original post by Cadherin)
    No problem

    Unless the examiner is a Vietnamese child marking your paper (which I wouldn't put past AQA), they will accept both 'reagents' and 'reactants' as synonymous.

    Besides, my chem teacher (and I think many others) refer to 'reagents' and not 'reactants'.
    Haha okay cool - thanks! x
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    Just found this good quizzlet for Transition Metal Colours https://quizlet.com/_2dfodx
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    (CuCl4)2-
    i know this is a green yellow solution
    do they accept just green solution?
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    For definition questions, which will surely come up in the exam- instead of learning the super long definitions, can we just write the equation. Eg Define enthalpy of dissociation. Answer: AB(s)-----> A+(g) + B- (g).

    Any cases where they don't allow this? -just saves time memorising definittions
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    (Original post by Lilly1234567890)
    (CuCl4)2-
    i know this is a green yellow solution
    do they accept just green solution?
    yeah, but best bet is to write yellow-green
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    DO we need to know the hydrogen fuel cell equations in alkaline conditions? or just acidic?
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    (Original post by Signorina)
    DO we need to know the hydrogen fuel cell equations in alkaline conditions? or just acidic?
    both.
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    (Original post by Lilly1234567890)
    (CuCl4)2-
    i know this is a green yellow solution
    do they accept just green solution?
    Markschemes have green/yellow solution. However, / means you can say either green OR yellow and still get the mark for either one. I state green/yellow solution to stay on the safe side, but you'd be fine.

    (Original post by OloMed)
    For definition questions, which will surely come up in the exam- instead of learning the super long definitions, can we just write the equation. Eg Define enthalpy of dissociation. Answer: AB(s)-----> A+(g) + B- (g).

    Any cases where they don't allow this? -just saves time memorising definittions
    That's fine, however you MUST state for any definition when using equation:

    The enthalpy change for (equation with state symbols)

    E.g define enthalpy of solution:

    The enthalpy change for
    AB(s) + aq -> A(aq) + B(aq)
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    (Original post by Suits101)
    Markschemes have green/yellow solution. However, / means you can say either green OR yellow and still get the mark for either one. I state green/yellow solution to stay on the safe side, but you'd be fine.



    That's fine, however you MUST state for any definition when using equation:

    The enthalpy change for (equation with state symbols)

    E.g define enthalpy of solution:

    The enthalpy change for
    AB(s) + aq -> A(aq) + B(aq)
    Super. Thanks. Don't see why people bother writing out long definitions!
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    (Original post by Signorina)
    DO we need to know the hydrogen fuel cell equations in alkaline conditions? or just acidic?
    Strictly speaking, you don't need to know them.

    In the exam they will tell you which equations to use, such as 'write the half equation at the hydrogen electrode in a hydrogen-oxygen fuel cell in acidic/alkaline conditions' or if they don't then you can use either one.

    I say you don't need to learn them because you need to know what happens at the electrodes, e.g you know hydrogen is a reactant so you can deduce how to get to hydroxide ions (if alkaline) or hydrogen ions (if acidic) and you know oxygen is a reactant so you can deduce how to get to hydroxide ions (if alkaline) or hydrogen ions (if acidic) once again.
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    Some help with oxidising and reducing agents?
    The strongest reducing agent has the most negative electrode potential and the weakest reducing agent has the most positive electrode potential
    The strongest oxidising agent has the most positive electrode potential and the weakest oxidising agent has the most negative electrode potential.
    Is that correct?
    So in this table Name:  ImageUploadedByStudent Room1466277155.356368.jpg
Views: 159
Size:  156.1 KB

    The STRONGEST R.A would be H2O2 and the WEAKEST R.A would be H2O

    The STRONGEST O.A would be H2O2
    and the WEAKEST R.A would be O2

    ???


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    Does anyone know why with [Co(H2O)6]2+ NH3 is able to fully displaced (by ligand substitution) all the H2O molecules however with [Cu(H2O)6]2+ only 4 H2O molecules will be displaced by NH3?
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    (Original post by 26december)
    Some help with oxidising and reducing agents?
    The strongest reducing agent has the most negative electrode potential and the weakest reducing agent has the most positive electrode potential
    The strongest oxidising agent has the most positive electrode potential and the weakest oxidising agent has the most negative electrode potential.
    Is that correct?
    So in this table Name:  ImageUploadedByStudent Room1466277155.356368.jpg
Views: 159
Size:  156.1 KB

    The STRONGEST R.A would be H2O2 and the WEAKEST R.A would be H2O

    The STRONGEST O.A would be H2O2
    and the WEAKEST R.A would be O2

    ???


    Posted from TSR Mobile
    Correct

    (Original post by shiney101)
    Does anyone know why with [Co(H2O)6]2+ NH3 is able to fully displaced (by ligand substitution) all the H2O molecules however with [Cu(H2O)6]2+ only 4 H2O molecules will be displaced by NH3?
    I read about it somewhere, however you don't need to know for the exam - just that it's an example of partial ligand substitution
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    (Original post by SirRaza97)
    2(b) The straight line equation y = mx + c can be used to represent the the gibbs free energy equation where y = ΔG, m = -ΔS x = T and c = ΔH. To calculate the gradient you just do the change in y divided by the change in x. So take two points on the line and find the corresponding y an x values and do the same for a second point and do this calculation:

    y1 - y2 / x1 - x2

    The slope is -ΔS so the units are J K-1 Mol-1

    2(d) is understanding that the rate of change of entropy changes for an element in it's different states. If the rate of change of entropy has changed then the slope (gradient) of your line has changed. So the ammonia has turned to liquid as the temperature is going lower.
    thank you !! how did you know m = -ΔS x = T
    could they ever ask us to work out ΔH using a graph like this, and if so,how would u do it?
    thanks once again!
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    can someone explain to me why when writing out cell representations using the SHE you always put H2 | H+ on the left hand side even if it has an E value more positive than the other species?? e.g. i did a question where i had to write the cell representation for Fe2+ being reduced to Fe (s) using SHE but it had an E value of -1.63 (or something like that)

    but surely SHE= 0V which is more positive than -1.63 so it should be written on the right?
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    (Original post by chzm)
    can someone explain to me why when writing out cell representations using the SHE you always put H2 | H+ on the left hand side even if it has an E value more positive than the other species?? e.g. i did a question where i had to write the cell representation for Fe2+ being reduced to Fe (s) using SHE but it had an E value of -1.63 (or something like that)

    but surely SHE= 0V which is more positive than -1.63 so it should be written on the right?
    May I ask, what is SHE/what does it stand for? I have never heard/come across it haha

    *** EDIT
    I reread it and realised what it is so ignore this messaged haha
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    http://filestore.aqa.org.uk/subjects...5-QP-JAN13.PDF

    can someone explain to me q3cii

    http://filestore.aqa.org.uk/subjects...W-MS-JAN13.PDF

    I just dont understand why the reverse reaction takes place ?
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    (Original post by chzm)
    can someone explain to me why when writing out cell representations using the SHE you always put H2 | H+ on the left hand side even if it has an E value more positive than the other species?? e.g. i did a question where i had to write the cell representation for Fe2+ being reduced to Fe (s) using SHE but it had an E value of -1.63 (or something like that)

    but surely SHE= 0V which is more positive than -1.63 so it should be written on the right?
    I think it's because you use the SHE to measure the E0 of that one particular half cell. Like on the table some of the reduction equations have a negative E0?
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    (Original post by Lilly1234567890)
    http://filestore.aqa.org.uk/subjects...5-QP-JAN13.PDF

    can someone explain to me q3cii

    http://filestore.aqa.org.uk/subjects...W-MS-JAN13.PDF

    I just dont understand why the reverse reaction takes place ?
    I'm not sure but could it be because the forward reaction is exothermic?
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    (Original post by lordyP)
    I'm not sure but could it be because the forward reaction is exothermic?
    i still dont get how that can lead to the reverse reaction ?
 
 
 
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