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    (Original post by jannattulfirdaus)
    hey guys,
    im new but i was wondering if anyone can help me with this question...
    6) step by step to make mayonaise and...
    how long it takes to sepearate
    ?

    I've never seen that anywhere, is it an F324 question? What paper is it.
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    (Original post by D4rth)
    ?

    I've never seen that anywhere, is it an F324 question? What paper is it.
    Hi, I think she is trolling!

    Want to revise
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    (Original post by jannattulfirdaus)
    hey guys,
    im new but i was wondering if anyone can help me with this question...
    6) step by step to make mayonaise and...
    how long it takes to sepearate
    I'll give you my mayonnaise if you want :cool:
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    (Original post by otrivine)
    Hi, I think she is trolling!

    Want to revise
    Sure, you start, I'll have to do the best I can, haven't started revision yet.
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    (Original post by D4rth)
    Sure, you start, I'll have to do the best I can, haven't started revision yet.
    no worries

    Describe electrophilic substitution in words (4)
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    (Original post by otrivine)
    no worries

    Describe electrophilic substitution in words (4)
    So you start with the hardest thing! :P *Grabs textbook*

    Substitution reaction when an electrophile (accepts a pair of electrons to form a dative covalent bond) is attracted to an electron rich centre and accepts a pair of electrons to form a new covalent bond. Something is also removed as it's substitution.

    Q: Compare the relative relative reactivity of bromine with cyclohexene and benzene (8)
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    (Original post by D4rth)
    So you start with the hardest thing! :P *Grabs textbook*

    Substitution reaction when an electrophile (accepts a pair of electrons to form a dative covalent bond) is attracted to an electron rich centre and accepts a pair of electrons to form a new covalent bond. Something is also removed as it's substitution.

    Q: Compare the relative relative reactivity of bromine with cyclohexene and benzene (8)
    Sorry but good your answer is partially correct!


    1) Bromine reacts more readily with cyclohexene than benzene. This is because cyclohexene contains pie-localised electrons sited above and below the plane of the carbon atom. The pi bond is rich in electron density, once the bromine appraches the double bond (C=C) in cyclohexene an electrophilic addition mechanism takes place, as the bromine molecule approaces the pie electron (bond) repels (in double sited above and below the carbon ring) the bromine molecule induces a dipole, forming Br deta+ and bromine deta -. The bromine that is more negative is because both of the electrons move to the bromine which makes it negatively charged and the type of bond breaking is heterolytic fission, the postively deta charged bromine is bonded to the carbon atom, the negatively charged bromine atom is attracted to the postively charged carbocation forming a new covalent bond. This shows that the cyclohexene has a higher (pie) electron density and has pie localised electron that can depolorise the bromine molecule.


    When benzene reacts with bromine no reaction takes place under normal conditions this is because benzene has pie delocolased electrons, is a stable molecule, has insufficnet pie electron density and less/no depolarisation of bromine molecule and hence, a halogen carrier is needed for reaction to take place.
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    (Original post by otrivine)
    Sorry but good your answer is partially correct!


    1) Bromine reacts more readily with cyclohexene than benzene. This is because cyclohexene contains pie-localised electrons sited above and below the plane of the carbon atom. The pi bond is rich in electron density, once the bromine appraches the double bond (C=C) in cyclohexene an electrophilic addition mechanism takes place, as the bromine molecule approaces the pie electron (bond) repels (in double sited above and below the carbon ring) the bromine molecule induces a dipole, forming Br deta+ and bromine deta -. The bromine that is more negative is because both of the electrons move to the bromine which makes it negatively charged and the type of bond breaking is heterolytic fission, the postively deta charged bromine is bonded to the carbon atom, the negatively charged bromine atom is attracted to the postively charged carbocation forming a new covalent bond. This shows that the cyclohexene has a higher (pie) electron density and has pie localised electron that can depolorise the bromine molecule.


    When benzene reacts with bromine no reaction takes place under normal conditions this is because benzene has pie delocolased electrons, is a stable molecule, has insufficnet pie electron density and less/no depolarisation of bromine molecule and hence, a halogen carrier is needed for reaction to take place.
    Good!
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    I've been at this questions for ages with no clue on how to move forward, could someone help please?

    Question 1.e) http://www.ocr.org.uk/Images/79471-q...d-analysis.pdf

    Thanks!
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    (Original post by XiLE)
    I've been at this questions for ages with no clue on how to move forward, could someone help please?

    Question 1.e) http://www.ocr.org.uk/Images/79471-q...d-analysis.pdf

    Thanks!
    It's pretty simple once you see what you need to do. If you look at the structure they give, it's the same answer but if you look at the carbon between the NH and C=O bond on the top and bottom if the structure, you add on the R group.

    It's basically the molecules forming bonds with themselves, just imagine another molecule attaching to the bottom of itself.

    I know I didn't explain very well... but I hope I kind of explained.
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    (Original post by D4rth)
    It's pretty simple once you see what you need to do. If you look at the structure they give, it's the same answer but if you look at the carbon between the NH and C=O bond on the top and bottom if the structure, you add on the R group.

    It's basically the molecules forming bonds with themselves, just imagine another molecule attaching to the bottom of itself.

    I know I didn't explain very well... but I hope I kind of explained.


    Describe transesterification (3)
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    I've got a question for you guys which Is the stronger base and why, phenyl amine or hexan1amine?
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    (Original post by Patel3000)
    I've got a question for you guys which Is the stronger base and why, phenyl amine or hexan1amine?
    hexan-1-amine because it readily accepts a proton and can undergo multiple nucleophilic substitution.
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    (Original post by otrivine)
    Describe transesterification (3)
    This is esterification but between Glycerol (Propane-1,2,3-triol) and a long fatty chain carboxylic acid which is unsaturated and it is trans (z) about the c=c double bond.

    Glycerol undergoes esterification with 3 molecules of the fatty acid eliminating water under a Conc. H2SO4 catalyst.
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    (Original post by D4rth)
    This is esterification but between Glycerol (Propane-1,2,3-triol) and a long fatty chain carboxylic acid which is unsaturated and it is trans (z) about the c=c double bond.

    Glycerol undergoes esterification with 3 molecules of the fatty acid eliminating water under a Conc. H2SO4 catalyst.
    No transesterification is involved in the process of making biodisel ? or am i WRONG
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    (Original post by Zaphod77)

    To get an A you need 480/600 over the whole A-level. You have 260+109+45(coursework)=414. This means that you need 66/90UMS in F324. To get an A* you need 270/300 for the A2 year - currently at A2 you have 109+45=154, so you would need 116/90 UMS for an A* in F324, which is impossible, sorry. You should be able to get an A, just work hard and you'll get there!
    how did you know 35/40 was 45 ums ?
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    Does anyone have any combined techniques questions (IR, mass spec and NMR)? I can't find more than a few on the internet and i've already done the ones in the book
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    (Original post by otrivine)
    No transesterification is involved in the process of making biodisel ? or am i WRONG

    Explain why it is bad to make a racemic drug [3]



    How do drug companies make a drug with no optical isomers? [3]
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    (Original post by Zzzyax)
    Explain why it is bad to make a racemic drug [3]



    How do drug companies make a drug with no optical isomers? [3]
    1) This is because there are 2 optical isomers , one of the isomers is pharmacologically active and has the good effect such as thalidomide, one of the isomer helps to treat morning sickness but the other isomer could have potentially adverse side effects such as in thalidomide the isomer that is harmful is that it leads to deformities in babies.

    2) By different methods, seprating isomer such as using enzymes as biological catalysts, chiral pool synthesis, using transition metal complexes.
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    (Original post by otrivine)
    1) This is because there are 2 optical isomers , one of the isomers is pharmacologically active and has the good effect such as thalidomide, one of the isomer helps to treat morning sickness but the other isomer could have potentially adverse side effects such as in thalidomide the isomer that is harmful is that it leads to deformities in babies.

    2) By different methods, seprating isomer such as using enzymes as biological catalysts, chiral pool synthesis, using transition metal complexes.
    1)Be more specific
    other optical isomers could have unwanted side effects
    increased dosage required
    cost of seperation

    2) good, but do you know what chiral pool synthesis is, or how transition metals are used
 
 
 
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