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Edexcel IAL Chemistry Unit 03B - 10th of May, 2017 Watch

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    (Original post by The Learn Ranger)
    Don't worry anyone!

    Exam boards now schedule international exams to take into account time differences. As far as we know there should be no problem discussing these exams as soon as they are finished.
    Oh
    So, there's no problem discussing the papers
    But I only asked that, coz I saw that when they were discussing the paper in January
    My apologies
    I'll delete my post asap
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    Whats the alternative in last question in biology yesterday
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      Just odne with the exam ! How did you find it?
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      (Original post by anotheruserontsr)
      Just odne with the exam ! How did you find it?
      I thought it was really good. how was it for you?


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        (Original post by Droneon)
        I thought it was really good. how was it for you?


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        Good too!!!
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        (Original post by annbee)
        All the same but for the last calculation I got 55.0 g dm^-3
        what did you guys get for how do we know that step 7 is complete?
        Also why did he wash the pipette with diluted vinegar rather than distilled water?
        And why is it better to wash with hydrochloric acid (the question where it said the acid donated a proton)?
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        (Original post by flyingfish3000)
        what did you guys get for how do we know that step 7 is complete?
        Also why did he wash the pipette with diluted vinegar rather than distilled water?
        And why is it better to wash with hydrochloric acid (the question where it said the acid donated a proton)?
        hcl is better than water because hcl is a stronger acid than water
        hcl donates proton more readily than water
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        (Original post by ahamed2000)
        hcl is better than water because hcl is a stronger acid than water
        hcl donates proton more readily than water
        i wrote that is because water is a weak proton donor.. will it be correct?
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        soo how did your chem ppr go?
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        what did you guys get for the moles of undiluted vinegar
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        Guys how was the paper ?
        do u think the boundaries will be lower or no?
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        Can someone pleeeeeze post an unofficial markscheme here ?
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        Yes we need the unofficial mark scheme!
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        Need unofficial mark scheme asap
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        (Original post by mandax_25)
        Yes we need the unofficial mark scheme!
        http://www.thestudentroom.co.uk/show....php?t=4700548 check this thread


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        (Original post by The Learn Ranger)
        Don't worry anyone!

        Exam boards now schedule international exams to take into account time differences. As far as we know there should be no problem discussing these exams as soon as they are finished.
        Haha Yes that's why I started discussing the paper. Sry for any trouble AND be fair to ur selves if we're wrong abt the timings.
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        This is all I could remember and gather if u guys know any questions add them here
        1. flame test colour; lilac
        cation; k+
        compound; KNO3
        2. gas that turns lime water milky; CO2
        cation present ; H+
        compound formed; barium sulphate
        solution B; H2SO4
        3. organic compound
        addition of PCl5 ; HCl gas evolved turning blue litmus paper red
        potassium dichromate added ; colour changes from orange to green.
        I think there was something about adding bromine water i dont remember but I wrote from brown to colour less
        4. experiment
        the diagrams; 1,heating under reflux,2. distillation under reflux( idk if correct cuz thats what I wrote)
        the process in term of change of state: it changes from liquid to gas and condenses back again due to the reflux condenser and goes back to liquid to react again.
        the layers named; above is aqueous and the lower one is organic
        why calcium chloride added; it serves as a drying agent
        volume I calculated by doing density= mass/vol Idk if correct
        5.titration: (this is what I did , correct me if I m wrong)
        ticked the second and third titre
        mean titre;22.9
        effect of pipette little drop left at the end; (Iwrote) yes it affects the mean titre because if even a drop of acid more is added the whole point of titration changes, there will be more NaOH needed to titrate the sol. thus changing the burette reading and the mean titre.


        This is all I can remember, if anyone knows additional questions add them
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        What I remember is
        Flame colour-lilac hence answer is K+
        Gas relights a glowing splint-hence answer is O2
        The compound is K2O
        Then the gas which turns limewater milky is C02
        the formula of ions is H+
        the solid is BaSO4
        and solution B is H2SO4
        then goes orange to colourless
        misty fumes, hcl gas which turns damp red litmus paper blue
        then orange to green
        then heat under reflux and diagram 2 was distillation
        then liquid evaporates to gas and gas condenses to liquid
        why did reaction take 45 minutes? The reaction is very slow
        the others for that question was calculation which were easy
        then the enthalpy change was -601 KJ
        then percentage uncertainty in burette was x2
        maximum temperature change was initial value -0,5 and final value +0.5 and then the difference
        the titrations we had to mark all of them and the mean was 29.9
        the moles of naoh was 0.1 x 29.9/1000
        the moles of undiluted vinegar was previous moles x 10
        then concentration was c=n/v
        and the g dm^-3 question was previous answer x60
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        Was the aqueous layer on the top or bottom?
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        (Original post by mandax_25)
        Was the aqueous layer on the top or bottom?
        (Original post by mandax_25)
        Was the aqueous layer on the top or bottom?
        yeah I did that wrong , it was suppose to be at the top not bottom the aqeous layer I meean
       
       
       
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