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Edexcel A2 Chemistry Exams -6CH04 (14th June) and 6CH05 (22nd June) Discussion Thread Watch

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    What order was the reaction based on the graph drawn:???? i got a straight diagonal line
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    Long answer questions

    Acid-base:
    Ka1 and Ka2
    work out the concentration at equlibrium
    work out pH
    write any assumptions you made
    Draw titration curve
    How to work out pKa from graph

    Entropy:
    Any hazards of the reaction
    Entropy of the system
    Why is it what you expected
    Entropy of surroundings
    Total entropy
    How would a change in temperature affect entropy
    Work out value of K from RlnK for Ba(OH)2
    Compare to solubility of Ca(OH)2

    Bromine clock reaction:
    Why phenol needs to be in small amounts
    Why others should be in excess:
    Include table value for rate:
    Plot graph
    Order wrt Bromine ions and why
    Rate equation and units
    Iodine clock reaction colour change:
    Measurement to be made to work out Ea:
    How to work out Ea (6 marker):

    Products of reaction between salicylic acid and NaOH
    Difference between alkaline and acidic hydrolysis
    salicylic acid and reagent to make acyl chloride:
    salicylic acid and reagent to make alcohol:
    Draw formula of product of salicylic acid + ethanol
    Difference between reaction of salicylic acid with ethanol and product D
    Draw NMR of ethanol and reasoning behind it
    Why does TMS produce sharp peak
    What sort of wave causes NMR
    Differences between salicylic acid and acyl chloride using infrared radiation:

    I think this was all the questions please add if you remember any more
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    (Original post by Cpj16)
    yes

    Are you gonna be doing the bio revsion session today, its at 11.30?
    Nah just gonna look at some redox stuff and then go sleep. Tomorrow is my full day of F214 focused revision
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    What was the value for entropy of system?
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    (Original post by C0balt)
    pH I got as 4.03 or 4.02 around that
    My answer refers to the multiple choice question for buffer solution. 4.03 was the pH of H2S
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    (Original post by Miracle1)
    What was the value for entropy of system?
    i got +971
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    (Original post by medi098)
    what did people put for the question where it asks how you would know that the h2so4 used to precipitate out the acid was in excess?:ashamed2:
    Add more H2SO4 and no more ppt will form.
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    (Original post by Chemstar_456)
    i got +971
    For system I believe I got around five hundred and something. I remember the total bring +47ish.
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    @chemstar_456 was the second to last question :What sort of wave causes NMR. or was it: what kind of radiation is involved in NMR? I am positive it is the latter but you said it was the other, not sure though?
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    (Original post by DesignPredator)
    For system I believe I got around five hundred and something. I remember the total bring +47ish.
    Yep got something around that value. what did everyone get for the multiple choice for the pH of the buffer was it 6.21?
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    (Original post by Hamzy45)
    Yep got something around that value. what did everyone get for the multiple choice for the pH of the buffer was it 6.21?
    Yep same 🙂
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    Anybody remember the total entropy value?
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    (Original post by DesignPredator)
    Yep same 🙂
    Thats good to hear, for the 2 mechanism questions what did you get for the answers in the MC?
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    (Original post by Chemstar_456)
    My answer refers to the multiple choice question for buffer solution. 4.03 was the pH of H2S
    Lol my brain is all mixed up now, I can't remember that MCQ value! But it was just plugging the numbers into the given equation right? In which case it couldn't have gone wrong... Hopefully lol Was it C? My brain vaguely remembers ticking a third one...

    (Original post by Ssttll)
    @chemstar_456 was the second to last question :What sort of wave causes NMR. or was it: what kind of radiation is involved in NMR? I am positive it is the latter but you said it was the other, not sure though?
    Well only radiation involved is radio wave anyway it doesn't matter what the wording was
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    What did youbguys put for the measurement required (that one marker before the six marker on ea?)
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    (Original post by lfcrules)
    What did youbguys put for the measurement required (that one marker before the six marker on ea?)
    Rate and temperature
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    (Original post by C0balt)
    Rate and temperature
    Wouldn't the measurement be the time taken for the colour change to occur, then one of the calculations is 1/time to find the rate.
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    (Original post by thedylanman)
    error/value*100

    e.g if a temperature is measure at 25 degrees and the error is +-0.5 degrees, 0.5/25*100
    Sorry my bad. if the error in a thermometer is +-0.5 degrees, the total error is 1 degree so percentage error is 1/25 *100
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    (Original post by thedylanman)
    Sorry my bad. if the error in a thermometer is +-0.5 degrees, the total error is 1 degree so percentage error is 1/25 *100
    when does the unofficial mark scheme come out??
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    what do people think marks will be awarded for on the activation energy 6 marker?
    i think
    1 mark - record measurements in a table
    1 mark- plot a graph of ln (k) or ln (rate) against 1/t
    1 mark - negative gradient & straight line ( correlation between the two)
    1 mark - gradient x R = -Ea
    not sure on the rest....
 
 
 
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