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    That's what I got
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    Ik I don't remember them and secondly I'm revising now so soz
    (Original post by OllieBiggs)
    Sorry but you've missed like 10 marks for C6
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    (Original post by ellamoon_22)
    How was it?? It was easy for me im taking it next year so im happy
    [I found it rather alright too, though the majority of people I've spoken to found it difficult. I'll type up what I believe will be the grade boundaries below! ]
    Markscheme of my answers

    C4

    1) atomic mass-12 (6 protons add 6 neutrons)

    Electrons or protons cant remember was 4 (mass take away protons)

    Configuration was 2.4 (6 electrons)
    [3]

    2) isotopes cause same atomic number but diff mass[3] [I thought this was only 2 marks?]

    [The following two questions focused on the advantages and disadvantages of super conductors. The first question asked you to recall two potential benefits of superconductors; any two of the following would have been acceptable-
    Loss-free power transmission
    Super-fast electronic circuits
    Powerful electromagnets
    The second question was worth one mark, and asked for one disadvantage of superconductors. Off of the top of my head, a disadvantage would be that they only operate at very low temperatures (below -268.8 degrees).


    3)covalent bonds of cl and F should be two overlapping circles with one pair of shared electrons
    [The question asked for you to draw a 'dot and cross' model for the bond between chlorine and fluorine. Although you could have drawn all of the electronic shells, you could have simply drawn the outer shell. In the past, drawing the outer shell has been acceptable for both marks.][2]

    4)mendeleev put elements on cards and arranged in order of properties and weight. Idea not accepted till gallium discovered [In 1869, Mendeleev arranged the elements in order in a table [1]. He noticed periodic changes in properties. From there, he was able to predict new elements [1].][2]

    5)iodide -grey solid astatine -320-340 allowance i think [I believe you also had to predict the melting point, though I'm not sure what it was.] [2]

    6)less reactive down group 7 because outer shell gets further away from nucleus so harder to gain electron [The nearer the outer shell is to the nucleus, the easier it is for an atom to gain one electron. The easier it is to gain the electron, the more reactive the halogen is.] [2]

    7)[6]
    it was copper chloride for compound A
    because precipitate was blue with sodium hydroxide
    compound B was iron (II) ...as precipitate was green i think cant remember
    Word equation forgot
    Balanced equation forgot

    8) super conductor used for medical scanners and powerful computers power transmission doesn't lose energy
    Disadvantage expensive to maintain low cost doesn't work at room temp[3] [Mentioned above as an earlier question.]

    Missing question? [There was a question following the dot and cross model which asked you to predict two properties of the compound. I'm not sure what I wrote, but the answer may have been something like low melting/boiling point due to the weak intermolecular forces?]

    C5

    1)number moles is 0.08[1]

    2)use reacting ratios to get 50g[2]

    3)i got 300 dm3 which is 300000cm3[2] [I'm not sure about this one.]

    4) titrations [6 mark]
    - ph starts high
    -ph decreases when acid added
    -ph decrease most near end point

    Concentration was 0.16 mol/dm3 or 0.08

    Volume was 40 cm3/ 20cm3 i wrote both just in case but i think 20

    5) they use less acid(/alkali ???) of 0.05 so less moles
    Graph would be lower than the first one lezs steep and reaction end slightly slower[2]
    6)catalyst[1]
    7)temp compromise balance between yield and rate increases rate of reaction
    [I believe you had to mention the fact that high temperatures force the equilibrium to the left, and because the equilibrium for the Contact process lies naturally to the right, this is detrimental. The high temperature is used to increase the rate of reaction, and, as you said, is a compromise.]

    Catalyst- increase rate not affect equilibrium

    low Pressure cheap pressure affects yield [High pressure is not required, as a high pressure would move the equilibrium further to the right, which is not necessary as the equilibrium already lies to the right. This saves money.]
    [3]

    8) Concentration is how many moles of acid are dissolved in 1dm3
    Strength is how much it ionizes. [2]

    9) Same volume produced cause same amount of reactants (and concentration). [1]
    10) High concentration of hydrochloric acid and more hydrogen ionize which increases frequency of collision. [2]
    11) White is chloride, bromide is cream, iodide yellow precipitates. [3]

    Total:25 marks

    C6

    [6 mark]
    - Oxidation is loss of electrons
    - Reduction is gain of electrons.
    - Copper gain electrons to form Cu atom
    - Iron loses to form an iron ion
    Word equations and balanced [Formula equations? This would be required to achieve a level 2 or above.]

    2) Chlorine radical is regenerated so destroy more ozone it is a chain reaction. [2]
    3) O3------O2+.... reaction 4?? [I chose reaction 2. Not too sure if that is right. [1]
    [There was another 2 mark question which asked you to describe how the Cl atoms separate themselves from the CFC molecules, in terms of bonding and electrons.]

    4) Prediction wrong because it only changed with soap not the other one [Washing up liquid.]. You had to be looking at water with calcium hydrogen carbonate (temporary hardness)[2]

    5) Ester[1]
    6) Bromine water / addition reaction alkene decolourises etc cant remember his results. [Double bonded/ alkene decolourises to form a dibromino compound. This is an 'additional reaction'.] [2]
    7) Margarine made from vegetable oil reacted with hydrogen and a catalyst. [Hydrogen is bubbled through the oil at about 200 degrees using a nickle catalyst. The reaction turns the carbon-carbon double bonds into single bonds.]
    [2]
    Section D

    1) On graph there was a decrease between 1977-1979 so this shows it was effective [There was a sudden peak at 1977, though the concentration was shown to slow in it's increase, therefore it was effective- to an extent. This may have been a 2 mark question.]

    2) [For the pie chart question, the second half of the question asked you to determine whether or not farming or residential use made the most impact of global warming; it was farming, as farming contributed the most to nitrous oxide and methane, which contribute to global warming. I believe the answer to the first one was nitrous oxide, but I'm not entirely sure what I wrote.]

    3) B more land more crops so more fertilizer needed [There was less agricultural land available in country B than country A, so more fertilizer was used perhaps to increase the crop yield to sustain the country.]
    Predictions for grade boundaries.
    The last couple of grade boundaries are as follows;

    2015- A*: 60, A: 50, B: 40, C: 30
    2014- A*: 62, A: 52, B: 41, C: 31
    2013- A*: 54, A: 45, B: 36, C: 28

    [Links: http://www.ocr.org.uk/i-want-to/convert-raw-marks-to-ums/]
    Despite my own opinion on the difficulty of the paper, the vast majority thought that this paper was relatively difficult, more so than past papers. On account of the comparative easiness of the first paper, I'd say that these grade boundaries will be lower than 60, though no lower than, say, 55.
    Predictions for 2016- A* 56, A: 46, B: 38, C: 30.

    Hope this helps. I appreciate feedback!
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    (Original post by GCShElpme)
    Predictions for grade boundaries.
    The last couple of grade boundaries are as follows;
    2015- A*: 60, A: 50, B: 40, C: 30
    2014- A*: 62, A: 52, B: 41, C: 31
    2013- A*: 54, A: 45, B: 36, C: 28
    [Links: http://www.ocr.org.uk/i-want-to/convert-raw-marks-to-ums/]
    Despite my own opinion on the difficulty of the paper, the vast majority thought that this paper was relatively difficult, more so than past papers. On account of the comparative easiness of the first paper, I'd say that these grade boundaries will be lower than 60, though no lower than, say, 55.
    Predictions for 2016- A* 56, A: 46, B: 38, C: 30.
    Hope this helps. I appreciate feedback!
    do you remember what question 1-3 of C5 and question 3 for C6 were about? I can't remember
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    (Original post by Str355ed)
    do you remember what question 1-3 of C5 and question 3 for C6 were about? I can't remember
    The first three for C5 were about precipitate reactions, I believe, while the first couple for C6 asked you about fats.
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    (Original post by GCShElpme)
    The first three for C5 were about precipitate reactions, I believe, while the first couple for C6 asked you about fats.
    For the C5 6 marker, wasn't the concentration 0.16? as it was (40x0.1)/25 or something like that - may be wrong? I've seen you highlighted it you see so was double checking to see if you agreed?
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    (Original post by Gamer_44)
    For the C5 6 marker, wasn't the concentration 0.16? as it was (40x0.1)/25 or something like that - may be wrong? I've seen you highlighted it you see so was double checking to see if you agreed?
    Yeah, I agree. I asked a couple of my friends, and we consulted our teacher, who got the same answer.
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    (Original post by Gamer_44)
    For the C5 6 marker, wasn't the concentration 0.16? as it was (40x0.1)/25 or something like that - may be wrong? I've seen you highlighted it you see so was double checking to see if you agreed?
    but you use the volume needed for it to reach the end point, which was 20cm^3?
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    (Original post by Vanilla Cupcake)
    but you use the volume needed for it to reach the end point, which was 20cm^3?
    Exactly! :erm:

    Posted from TSR Mobile
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    I wish I revised.
    I would've finished the paper would've been faster.
    Think I got an A lol needed a good A*, but oh well.
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    I got 0.08 as the concentration on the six marker
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    (Original post by leopard923)
    Exactly! :erm:

    Posted from TSR Mobile
    The equation = volume of acid x concentration of acid = volume of alkali x concentration of alkali.

    What I don't understand is where it says you have to use the 'end point'.

    I understand what you mean but the volume of acid was continued beyond the end point?
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    (Original post by mxskaan)
    For the C4 6 marker it was copper chloride for compund A and compound B was iron (II) bromide.

    For the C5 6 marker I got 0.08mol/dm3 of NaOH.

    For C6 I got Fe + CuSO4 --> FeSO4 + Cu. Fe oxidised. Cu reduced.


    Posted from TSR Mobile
    What did you get for the volume of gas at RTP?
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    (Original post by Wolfram Alpha)
    What did you get for the volume of gas at RTP?
    0.08 mols and 1920cm^3

    Posted from TSR Mobile
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    (Original post by Wolfram Alpha)
    What did you get for the volume of gas at RTP?
    What was the exact question again?
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    (Original post by JickDee)
    But didnt it say that only 18% of the land was agricultural land in the table?
    So you had to multiply 1.26 billion by 0.18 to get the actual amount?
    Yes. Your method is the correct one.
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    (Original post by OllieBiggs)
    What was the exact question again?
    There's 0.16g of hydrogen, what's the volume of this has at RTP? I got 300,000 but am certain my answer is incorrect.
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    (Original post by mxskaan)
    0.08 mols and 1920cm^3

    Posted from TSR Mobile
    Argh, I divides rather than multiplied!
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    (Original post by Wolfram Alpha)
    There's 0.16g of hydrogen, what's the volume of this has at RTP? I got 300,000 but am certain my answer is incorrect.
    Pretty sure it was 1920cm^3

    This is because 1mole of H2 = 24000cm^3 = 2g

    1g H2 = 12000cm^3

    0.01g H2 = 120

    0.16g H2 = 1920

    But I may be wrong

    HAVING SAID THAT

    I put 3840cm^3

    This is because (24000/100) * 16

    Have a look here: http://www.thestudentroom.co.uk/show....php?t=4176844
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    (Original post by Wolfram Alpha)
    Argh, I divides rather than multiplied!
    Oh no! How many marks was it? I'm sure you'll definitely get 1 at least.

    What I did was mass/mr = mols
    0.16g/2 (H2 =1×2)
    This got me 0.08 mols
    1 mol = 24000cm^3
    Divide 24000 by 12.5 bc 1/12.5 = 0.08

    Posted from TSR Mobile
 
 
 
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