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    How did everyone find it?
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    I thought it was ok.
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    (Original post by LearningMath)
    I thought it was ok.
    I think, overall it was alright... but there are some hard questions..


    Like that Nylon + water one... :confused: bit confusing..


    And the moles calculation... evry1 in my class had a different answer.... Thats abit ridiuclous...
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    Also, didnt expect the nucleophilic substitution there... forgot all about it since last year
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    I think it was nucleophilic addition, if memory serves correct it was a cyanide ion attacking an aldehyde?
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    yea it was nucleophilic addition

    what did yous get for the calculation?
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    (Original post by LearningMath)
    I think it was nucleophilic addition, if memory serves correct it was a cyanide ion attacking an aldehyde?
    I had no idea... Didnt think nucleophilic addition/substitution would come into it... Didnt come across it at all when in class or revising... :mad2:

    *sigh* maybe another resit in June then... :rolleyes:

    But yeah, it was CN attacking an aldehyde... how did you draw the curly arrows? and what ion forms as ar esult?
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    75.03%, possibly lost mark for sig figs, i cant remember how many they used in given values.

    Errr... what other questions were there? Oh yes, when the polymer is hydrolyised with NaOH. I gave the products as ^-OOC-CH2-CH2-CH2-CH2-CH2-NH2....
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    (Original post by LearningMath)
    75.03%, possibly lost mark for sig figs, i cant remember how many they used in given values.

    Errr... what other questions were there? Oh yes, when the polymer is hydrolyised with NaOH. I gave the products as ^-OOC-CH2-CH2-CH2-CH2-CH2-NH2....
    Yea i got 75% so not sure if sfs are right.

    And i got the same for the product but i put Na^+ next to the COO^-
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    (Original post by LearningMath)
    75.03%, possibly lost mark for sig figs, i cant remember how many they used in given values.

    Errr... what other questions were there? Oh yes, when the polymer is hydrolyised with NaOH. I gave the products as ^-OOC-CH2-CH2-CH2-CH2-CH2-NH2....
    75.03 % ?

    Argh.. What was the question again...

    Cant remember too clearly, but I think I got around 20%
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    Lmao, yeh i probably should have written in the Na^+ ion... some past papers have excused it though so i'l hope they do again!

    What about the potassium manganate question. I found order to be 1st order as half-life was ~constant, and for the concentration one i just pointed out that the other reactants were in excess therefore connc ~constant.
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    Also how did the hydrolysis of the nylon affect the Tg?
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    Yes i did did you?

    I found this exam very hard but im hoping i wont have to resit in june.

    what did you get for the glass transition question?
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    Something along the lines of:

    -nylon-6 has secondary amide group, N-H and C=O in this group have large dipoles, hence able to form hydrogen bond to water. (Explaining why it absorbs)
    -Water molecules disrupt the crystalline structure of polymer, so chains cannot fit together as closely and in such an orderely manner, results in weaker intermolecular forces. So Tg is lower.
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    I found the questions on the DNA bits quite diffcult, which is stupid because i do biology! But yeh didn't know what the condentsation reaction of the phosphate group etc looked like. Hoping for relatively low grade boundaries but we shall see. Exams done... PHEW.... all will be retaken but still
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    (Original post by 3107a)
    I found the questions on the DNA bits quite diffcult, which is stupid because i do biology! But yeh didn't know what the condentsation reaction of the phosphate group etc looked like. Hoping for relatively low grade boundaries but we shall see. Exams done... PHEW.... all will be retaken but still
    The phosphate question is on page 47 in storylines...that was my last exam too
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    I hated that nylon question and the 7 mark % mass question was just annoyingly long.
    Got to the end though :P
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    (Original post by Eccentric)
    I hated that nylon question and the 7 mark % mass question was just annoyingly long.
    Got to the end though :P
    Was it 7 marks just for 75%?! I hope they can make sense of my working lol...:p:
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    (Original post by LearningMath)
    Was it 7 marks just for 75%?! I hope they can make sense of my working lol...:p:
    Yeah I am sure it was 7 , got as far as doing both conc. equations and then looked at the time and carried on :p:
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    I think it was 6 marks in total.

    Can any one remember what the % mass question was?
 
 
 
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