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    How many marks would I get more the energy density one .. I calculated mr as 112 and divided -5700 or what ever it was by 112 = -47 and the did 2 sig fig ... 1 pr 2 marks ?


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    (Original post by CameronLee)
    Thought this exam ws okay , dropped about 7-8 marks ... What did envy one put for the extra information needed ... No of moles of the hydrocarbon ?
    Nope, Mass of fuel at start of combustion and mass at the end. To calculate mass of fuel burnt.
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    (Original post by Isaacymoose)
    I put mass/volume of hydrocarbon. Which could be used to calculate moles so both could be correct!
    Neither will get the marks. look in the cgp, has to be difference between start and end mass of the fuel.
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    (Original post by Richyp22)
    Nope, Mass of fuel at start of combustion and mass at the end. To calculate mass of fuel burnt.
    It will be moles to calculate enthalpy change


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    QP:
    https://docs.google.com/viewer?url=h...y-for-life.pdf
    MS:
    https://docs.google.com/viewer?a=v&q...abCxOrbBFvXLlw

    For question 3dii is it okay to say the following:
    "The catalyst poison blocks a catalyst's active site and so prevents reactant molecules from being adsorbed onto the catalyst surface."

    ??

    thanks so much!
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    Is that the paper ^^


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    (Original post by krisshP)
    QP:
    https://docs.google.com/viewer?url=h...y-for-life.pdf
    MS:
    https://docs.google.com/viewer?a=v&q...abCxOrbBFvXLlw

    For question 3dii is it okay to say the following:
    "The catalyst poison blocks a catalyst's active site and so prevents reactant molecules from being adsorbed onto the catalyst surface."

    ??

    thanks so much!
    Nope, you'll get nothing for saying active site thats biology tbh. Marks will be for - So you'll get 1 maybe 2/2

    -Poisen coats catalysts surface
    - Preventing reactants from adsorbing onto catalysts surface
    - Therefore catalyst cant get involved in the reaction
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    (Original post by krisshP)
    QP:
    https://docs.google.com/viewer?url=h...y-for-life.pdf
    MS:
    https://docs.google.com/viewer?a=v&q...abCxOrbBFvXLlw

    For question 3dii is it okay to say the following:
    "The catalyst poison blocks a catalyst's active site and so prevents reactant molecules from being adsorbed onto the catalyst surface."

    ??

    thanks so much!
    I don't think active sites are involved .. I put binds more strongly than reactant molecules , coats surface , reactants can't adsorb


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    Predicted grade boundaries 48/50 = A


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    what were the bond angles for A and B ? I put 120 for both, thinking they both had 3 areas of electron density - but did the one w/o the double bond have a lone pair and therefore 109?
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    (Original post by Tikara)
    what were the bond angles for A and B ? I put 120 for both, thinking they both had 3 areas of electron density - but did the one w/o the double bond have a lone pair and therefore 109?
    I put 120 for first one and got the second one wrong , but because it was skeletal there was another hydrogen bond so it turned out to be tetrahedral


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    (Original post by Richyp22)
    Nope, you'll get nothing for saying active site thats biology tbh. Marks will be for - So you'll get 1 maybe 2/2

    -Poisen coats catalysts surface
    - Preventing reactants from adsorbing onto catalysts surface
    - Therefore catalyst cant get involved in the reaction
    yeah, but isn't that a bit too picky??

    thanks anyway
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    (Original post by CameronLee)
    It will be moles to calculate enthalpy change


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    Bra look in the cgp for your answer. Im correct.

    (Original post by Tikara)
    what were the bond angles for A and B ? I put 120 for both, thinking they both had 3 areas of electron density - but did the one w/o the double bond have a lone pair and therefore 109?
    Nope second one is 109 because theres also a hydrogen bond around the carbon atom, its skeletal so you cant see it on the diagram
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    (Original post by krisshP)
    yeah, but isn't that a bit too picky??

    thanks anyway
    Yes probably, but you wont get anything for active site. Ms answer will probably be.

    -Coats surface -prevents adsorption
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    what about catalyst adsorbed on surface too stongly, prevents catalysis
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    (Original post by Richyp22)
    Yes probably, but you wont get anything for active site. Ms answer will probably be.

    -Coats surface -prevents adsorption
    thanks! good luck to you

    I got my mock tommorow of F331 so I probably will be doing the same paper as you.
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    (Original post by Richyp22)
    Neither will get the marks. look in the cgp, has to be difference between start and end mass of the fuel.
    Yeah so you need to know the mass of the fuel.
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    (Original post by Richyp22)
    Bra look in the cgp for your answer. Im correct.



    Nope second one is 109 because theres also a hydrogen bond around the carbon atom, its skeletal so you cant see it on the diagram
    daaaaaaaaaaaaaaaarn it!! little things like this are gonna mess my mark up -completely forgot it was skeletal
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    (Original post by Richyp22)
    Nope, you'll get nothing for saying active site thats biology tbh. Marks will be for - So you'll get 1 maybe 2/2

    -Poisen coats catalysts surface
    - Preventing reactants from adsorbing onto catalysts surface
    - Therefore catalyst cant get involved in the reaction
    Active sites have been in F331 mark scheme before- pretty sure he will get the mark for it. All catalysts have active sites but yep your three points would be better lol

    Okay legit grade boundaries for this paper? Doubt 48/50 will be an A but I do think they'll be high.
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    the mark scheme are so annoying and picky!!!!
 
 
 
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