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    (Original post by girl :D)
    i didn't put partial charges on the compounds in any of the mechanisms how many marks do u guys think i'll lose
    I didn't think AQA asked for the whole delta-/delta+ partial charges on mechanisms? I looked on last years mark scheme and the mechanism didn't have partial charges on
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    Guys I'm pretty sure there was a double bond in the alcohol. The molecular formula was C4H8O for A and B and C4H10O for P and Q
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    (Original post by jessyoung)
    Guys I'm pretty sure there was a double bond in the alcohol. The molecular formula was C4H8O for A and B and C4H10O for P and Q
    Can someone put together mark scheme please?
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    I thought the paper was actually quite a good paper - that may be because I had to cope with the unit physics yesterday (which was tough). So I won't be acidifying bleach anytime soon.
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    Does anyone know the answer to why acidifying bleach is dangerous question, I really didn't get it so i just put down that Nacl and Naclo are already acidic so acidifying further would give a strong acid which is dangerous as corrosive-but that seems way too simple to be correct. :/
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    (Original post by nooonooo)
    Does anyone know the answer to why acidifying bleach is dangerous question, I really didn't get it so i just put down that Nacl and Naclo are already acidic so acidifying further would give a strong acid which is dangerous as corrosive-but that seems way too simple to be correct. :/
    because it was an equilibrium, although the product was NaCl and not Cl-, I wrote that it could form HCL and that would be dangerous...complete guess
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    (Original post by nooonooo)
    Does anyone know the answer to why acidifying bleach is dangerous question, I really didn't get it so i just put down that Nacl and Naclo are already acidic so acidifying further would give a strong acid which is dangerous as corrosive-but that seems way too simple to be correct. :/
    The eq. is NaOH + Cl2 <-> ClO- + H+ + NaCL

    If you add acid you incr. the conc. of H+ Ions which will cause the eq. to shift left, thus producing Cl2 which is toxic.
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    (Original post by AngryRedhead)
    What will happen if we want to retake after this year? Can we resit these again or would you have to do all of the new spec a-level exams from scratch?
    You wouldn't be able to resit AS but you would be able to resit A2
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    (Original post by RME11)
    The eq. is NaOH + Cl2 <-> ClO- + H+ + NaCL

    If you add acid you incr. the conc. of H+ Ions which will cause the eq. to shift left, thus producing Cl2 which is toxic.
    Isnt it 2NaOH + Cl2 -> NaClO + NaCl + H2O?
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    Hi i also made a mistake on the fermentation one and spoke about advantages and disadvantages of hydration rather than fermentation. Did u find out if we lose or gain marks as we did imply the points.
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    (Original post by Jackmilne95)
    Isnt it 2NaOH + Cl2 -> NaClO + NaCl + H2O?
    Yes that's the correct equation.

    I don't know what would be the correct answer to the question but I'm assuming they wanted us to say the H+ would react with the OH- ions on the LHS which would remove them, so equilibrium would shift to the left to oppose the decrease of OH- and would produce more toxic Cl2 gas.

    I fluffed up and said it would react with the NaCl to form HCl but I don't think that's right.
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    (Original post by Hopefulmedic15)
    Yes that's the correct equation.

    I don't know what would be the correct answer to the question but I'm assuming they wanted us to say the H+ would react with the OH- ions on the LHS which would remove them, so equilibrium would shift to the left to oppose the decrease of OH- and would produce more toxic Cl2 gas.

    I fluffed up and said it would react with the NaCl to form HCl but I don't think that's right.
    Ok cool. I just said that acidifying the solution would cause the equilibrium to shift to the left to oppose the increase in H+ ions and so the conc/moles of chlorine gas would increase and chlorine gas is toxic in high concs
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    (Original post by EmmaHarvard)
    Can someone put together mark scheme please?
    Put together some rough answers on page 12 for quite a few questions. They should all be correct
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    Hey does anyone know how many marks in total question 9 was?
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    (Original post by RME11)
    The eq. is NaOH + Cl2 <-> ClO- + H+ + NaCL

    If you add acid you incr. the conc. of H+ Ions which will cause the eq. to shift left, thus producing Cl2 which is toxic.
    ahhh, thank you, don't know why I didn't think to write out the equation
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    Did you guys tick the box 'oxidising agent'?
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    (Original post by girl :D)
    omd yes!!!!!!!!!!!!!!
    Hate to break this ...

    They ignore partial charges UNLESS they are incorrect. If they are wrong, they penalise you.
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    (Original post by jessyoung)
    Guys I'm pretty sure there was a double bond in the alcohol. The molecular formula was C4H8O for A and B and C4H10O for P and Q
    yeah there had to be one, it was a tertiary alcohol too right?
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    Is the paper you guys did different from the one the yr 12s did? i cant remember any of these questions
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    hey guys im in A2, i didnt do the unit 2 test, but to summarise how did people find it?
    were there a lot of curveballs, like were questions weirdly written

    trying to prepare for my chem 4 paper on tuesday
 
 
 
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