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    Was Gibbs free worth 3 marks?

    Also can anyone confirm for MgCl2 solubility one:

    Solubility decreases
    Forward reaction is exothermic
    Equilibrium shifts left to oppose increase in temperature
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    (Original post by Aerosmith)
    Na isn't in its standard state so formation of 1 mol would not be required. Do you now see the logic?
    No.
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    how many marks do you lose for not converting degrees to kelvin?
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    (Original post by Parallex)
    No.
    I think you're just a stubborn nerd who can't accept that it was perfectly fine to divide by 2 and work it out
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    (Original post by j5994)
    oh **** yeah ur right, ah well should only be one mark right?
    Lets both just prey :/
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    (Original post by Suits101)
    It came up!!!
    wtf is the chelate effect?
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    (Original post by Aerosmith)
    Na isn't in its standard state so formation of 1 mol would not be required. Do you now see the logic?
    I'm sorry, with all due respect aerosmith, that comment (plus perhaps most/all of your previous comments you've written in this discussion) is just absolute nonsense.

    Na isn't in its standard state? Ok... isn't that why it's delta H value isn't 0 then?

    I'm sorry, to be honest I've got no idea what 'logic' you refer to, but long story short Parallex has used an absolutely valid reference to a question and there's nothing that prevents comparison of that question with the one in our exam
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    (Original post by Suits101)
    Was Gibbs free worth 3 marks?

    Also can anyone confirm for MgCl2 solubility one:

    Solubility decreases
    Forward reaction is exothermic
    Equilibrium shifts left to oppose increase in temperature
    Solubility one- AGREED
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    (Original post by Aerosmith)
    I think you're just a stubborn nerd who can't accept that it was perfectly fine to divide by 2 and work it out
    So right I can't wait for people to see the paper again because it asked for delta Hf
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    (Original post by Suits101)
    Was Gibbs free worth 3 marks?

    Also can anyone confirm for MgCl2 solubility one:

    Solubility decreases
    Forward reaction is exothermic
    Equilibrium shifts left to oppose increase in temperature
    YES! I got this, but people were telling me it's wrong. I think I've dropped 3 marks in total, I don't want a CE and to make it 6!!
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    (Original post by RME11)
    No it wont be right, because you have divided your enthalpy by 2 and I presume your entropy by 2 - you can expect to drop 2/3 marks.

    Next time don't take to TSR trying to tell the 95% of people who didn't get your answer that they are wrong, causing unnecessary stress for people.
    Drop 2 marks if its wrong.

    I always write what I have done and I said I BELIEVE that's what you do unless I am certain, you can check my posts.

    I have never said that's the proper way to do it because of that reason, and I don't want to argue with you (especially because I have a final exam tomorrow and I don't see the need).
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    Jesus people, it's chemistry not game of enthalpy changes
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    Do you divide by 2 or not this is doing my head in now
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    (Original post by Spectral)
    I'm sorry, with all due respect aerosmith, that comment (plus perhaps most/all of your previous comments you've written in this discussion) is just absolute nonsense.

    Na isn't in its standard state? Ok... isn't that why it's delta H value isn't 0 then?

    I'm sorry, to be honest I've got no idea what 'logic' you refer to, but long story short Parallex has used an absolutely valid reference to a question and there's nothing that prevents comparison of that question with the one in our exam
    To be honest with you, I think it's poor wording on AQA's part and so both should be accepted
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    For the dividing by 2, I was looking at the question in the exam trying to figure out whether it was necessary or not! I think that if answers are given as for example: -189 kj for the enthalpy change for the reaction then that's fine, and if given as -94.5 kj mol-1 that's also fine. Both are the same it's just the units that change and I think if you changed units depending on your answer you should get the marks. Agree?
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    (Original post by Aethrell)
    oh for ****s sake, completely forgot
    Are we sure it said under standard conditions?
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    (Original post by _newbe)
    So right I can't wait for people to see the paper again because it asked for delta Hf
    No, it definitely didn't. It gave you Hf values in a table but it asked you to work out the standard enthalpy change for for the reaction shown.
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    Solubility question stated that solubility was mentioned as the amount of present MgCl2(s) available to dissolve in aq solution, and as the reaction went backwards, more MgCl2(s) was produced, and hence the solubility was increased, not descreased

    Either way increase or decrease, as long as your explanation was correct, then I believe you will get a minimum of 2/3
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    (Original post by palacefloor)
    wtf is the chelate effect?
    Substitution of unidentate ligands (water in this question) by bidentate (ethane-1,2-diamine in this question) or multidentate ligands leads to a more stable complex because of the increase in the number of particles so disorder increases, entropy increases, delta H is approximately 0 and delta G <= 0

    (Original post by OloMed)
    Solubility one- AGREED
    (Original post by Cadherin)
    YES! I got this, but people were telling me it's wrong. I think I've dropped 3 marks in total, I don't want a CE and to make it 6!!
    Excellent!

    I don't see why it is... exactly I think I'm in the 90's too...
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    Lets get this straight
    1 mark for equation 2:5 ratio
    2nd mark for no of moles of Mno4- 0.02x(26.4/1000)
    3rd mark for finding moles of C2o4- using the ratio 0.00132
    4th mark for x10 to find in original 250 cm3
    5th mark for x by 88 Mr of C2O4 to get 1.16 as this is specifically for the total C2o4 present before titre so up to this point definitely right
    6th mark for the Mr of C2o4 which is 88
    7th mark for dividing by 2.29 or something then times 100% to get the percentage as 50.7
    Here are the official 7 marks for this question as both the 50.7 and 94.4% answers concern C2o4 pressent in the original sample 94.4 gives 8 marks whilst this is a 7 marker so why isnt this paper out of 101 dalmations
 
 
 
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