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    (Original post by joseph2008)
    What did you guys get for the Pb electrode question?
    i think my answer was -0.46 but im not too sure i cant remember
    im hoping to get an A on this after my bio exam was :mad:
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    (Original post by hahaff)
    i think my answer was -0.46 but im not too sure i cant remember
    im hoping to get an A on this after my bio exam was :mad:
    I got -0.46 too...fnk thats ryt. Another mark in the bag lol
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    (Original post by superminh21)
    Could anyone tell me how F- ion is dissociated in water ? I mentioned H bonding between F and H but I'm not sure. Another posibilitiy is F- accept electron pair from H2O to form coordinate bonds but it is quite strange as H2OF- is never heard by me before !! Any idea ? It is a 3 mark question, and as you see, I cannot sleeep!
    Well, i also put hydrogen bonding, and according to chemguide, it seems to be right

    This is from chemguide:

    The hydration of negative ions

    When an ionic substance dissolves in water, water molecules cluster around the separated ions. This process is called hydration.

    Water frequently attaches to positive ions by co-ordinate (dative covalent) bonds. It bonds to negative ions using hydrogen bonds.

    I'm hoping that's what the markscheme wants though!
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    (Original post by Wish I Could Change This)
    I'm going to keep my hopes up then, thank you
    any idea how much you could drop for an A*? I was under the impression it was 80% for an A and 90 for an A*
    It's usually about 81-83% raw marks for an A*
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    (Original post by Betsss)
    Well, i also put hydrogen bonding, and according to chemguide, it seems to be right

    This is from chemguide:

    The hydration of negative ions

    When an ionic substance dissolves in water, water molecules cluster around the separated ions. This process is called hydration.

    Water frequently attaches to positive ions by co-ordinate (dative covalent) bonds. It bonds to negative ions using hydrogen bonds.

    I'm hoping that's what the markscheme wants though!
    I didn't mention hydrogen bonds but I said that the F- ion acts as an lewis base. Does that sound ok?
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    (Original post by soutioirsim)
    I didn't mention hydrogen bonds but I said that the F- ion acts as an lewis base. Does that sound ok?
    I would think so! considering a lewis base essentially donates a lone pair of electrons to the H (which is kindaa like a in a H bond)
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    (Original post by soutioirsim)
    What did people put for the "How do the fluoride ions interact with the water?" Or something a long the lines.

    I put that the fluoride ions act as a lewis base :s
    I put that too!
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    (Original post by A level Az)
    It asked specifically for the ionic equations, so I wouldn't expect them to give any marks for that. Sorry
    What if you put the ionic equation but included the spectator ions?
    I read that it said ionic, and then had a bit of a meltdown and forgot the concept of what one was, so I wrote down the full equation as ions if you know what I mean
    Do you think that would get any credit?
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    (Original post by A level Az)
    You'll get method marks, so maybe 1/3 or 2/3 depending on how they do it (I think it was out of three?)

    I was under the impression that you'd only get full marks if you used the correct answer, or the value they gave you, as it would be a nightmare for examiners to work out calculations to figure out of people have been using the right method with their incorrect answer.
    Well if loads of people didn't divide by two then the majority of wrong answers would be the same which wouldn't be that hard to mark.
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    (Original post by freya(:)
    Well if loads of people didn't divide by two then the majority of wrong answers would be the same which wouldn't be that hard to mark.
    Yeh i get what your sayin...but i think we'd stil only get method marks, although if LOADS of peeps made the mistake then it might mean lowering the grade boundaries to cancel the mistake out, but im just guessing! Lol
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    (Original post by Zakir)
    Yeh i get what your sayin...but i think we'd stil only get method marks, although if LOADS of peeps made the mistake then it might mean lowering the grade boundaries to cancel the mistake out, but im just guessing! Lol
    Mmm well its pretty illogical for aqa to not give you marks for something you're doing right ie: the g=h-ts equation... So im assuming that if you get an answer correlating to the wrong enthalpy/entropy value it still shows you've done the equation correctly. Im really hoping the allow error carried forward, a few people on here are saying it and OCR physics a level allow it. I mean obvs you'd lose a couple of marks in the first couple of questions for not dividing by two but after that it would be really unfair of them to penalise you for it.
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    (Original post by hunter'sdaughter)
    I put that too!
    Swweeeeet, I hope it's right
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    (Original post by Pendulii)
    What if you put the ionic equation but included the spectator ions?
    I read that it said ionic, and then had a bit of a meltdown and forgot the concept of what one was, so I wrote down the full equation as ions if you know what I mean
    Do you think that would get any credit?
    Yeah I get what you mean; there really is no way to tell how many marks you'd get unless you can find a similar question on a past paper and look at what they state in the mark scheme. You could get two, one, or nothing, but I'd guess you would get one out of the two as they might not penalise you twice for including spectator ions.
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    (Original post by freya(:)
    Well if loads of people didn't divide by two then the majority of wrong answers would be the same which wouldn't be that hard to mark.
    Yeah sometimes they do have a "wrong answer" list, but not always, so I guess my point still makes sense.
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    theres someone on here who has the paper
    plz cud u upload it please scan it please
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    (Original post by hahaff)
    theres someone on here who has the paper
    plz cud u upload it please scan it please
    this
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    guys how many marks was the first question
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    did anyone get 53.7 for the percentage for the dichromate question
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    enthalpy sol for caf2 (lattice caf2 =-2611 enthalpy hyd for ca2+ = -1650 enthalpy hyd f- = -506)

    Did people get 455 for this?
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    (Original post by SnookerLoopy)
    enthalpy sol for caf2 (lattice caf2 =-2611 enthalpy hyd for ca2+ = -1650 enthalpy hyd f- = -506)

    Did people get 455 for this?
    i think i did but i cant really remember
    u knw for the first question was it out of 7 marks
 
 
 
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