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OCR Chemistry F322~ 4th June 2013~ AS Chemistry Watch

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    (Original post by joe1545)
    So how does everyone feel about this paper, im new to this thread, i think it could either go quite well or really bad...

    Few questions for anyone to try....
    'Describe the green house affect, and how it is created (8 marks)
    3 greenhouse gases : carbon dioxide, water vapour, methane
    Their covalent bonds absorb infra red radiation and vibrate.
    Strength of greenhouse gases dependant on atmospheric concentration and ability to absorb infra red
    The greenhouse gases emit this infra red radiation onto earth surface causing it to heat up
    Leading to global warming.......followed by examples

    That's all I can think of but I doubt such a question would come
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    (Original post by niceguy95)
    3 greenhouse gases : carbon dioxide, water vapour, methane
    Their covalent bonds absorb infra red radiation and vibrate.
    Strength of greenhouse gases dependant on atmospheric concentration and ability to absorb infra red
    The greenhouse gases emit this infra red radiation onto earth surface causing it to heat up

    That's all I can think of but I doubt such a question would come
    one more thing, residence time - the amount of time the gas stays in the atmosphere
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    (Original post by jenny1995)
    Is there any chance someone could please explain question 2d on the May 2012 paper? It says

    Ethane-1,2-diol reacts with an excess of ethanoic acid CH3COOH, in the presence of an acid catalyst. A compound is formed with the molecular formula C6H10O4. Draw the structure of this compound.

    Thanks
    righto
    first things first draw out ethane-1,2-diols
    H H
    I I
    H-C-C-H
    I I (you can put the diols whereever you like- but remember keep it simple)
    OH OH

    Next step, in the question we are told it reacts with 'excess ethanoic acid'
    'ethanoic acid' should remind you of esterification
    we also know that the molecules will react with excess ethanoic acid to form an ester
    O H
    II I
    ethanoic acid= C-C-H
    I I
    OH H

    ester= -O- bonds
    excess= as many -O- bonds as possible!!!
    so you should end up with:
    H O H H O H
    I II I I II I
    H-C-C-O-C-C-O-C-C-H
    I I I I
    H H H H

    in red is your original ethane-1,2-diol
    in black are the 2 ethanoic acid molecules- there are 2 because each OH reacted with the OH of the ethane-1,2-diol
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    Can soneone help me with this? I have no idea how to do this question... like No idea!!!!!

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    (Original post by anonymousecheese)
    righto
    first things first draw out ethane-1,2-diols
    H H
    I I
    H-C-C-H
    I I (you can put the diols whereever you like- but remember keep it simple)
    OH OH

    Next step, in the question we are told it reacts with 'excess ethanoic acid'
    'ethanoic acid' should remind you of esterification
    we also know that the molecules will react with excess ethanoic acid to form an ester
    O H
    II I
    ethanoic acid= C-C-H
    I I
    OH H

    ester= -O- bonds
    excess= as many -O- bonds as possible!!!
    so you should end up with:
    H O H H O H
    I II I I II I
    H-C-C-O-C-C-O-C-C-H
    I I I I
    H H H H

    in red is your original ethane-1,2-diol
    in black are the 2 ethanoic acid molecules- there are 2 because each OH reacted with the OH of the ethane-1,2-diol

    Oh dear my molecules were not meant to look like that- i think when i submitted the reply it got all crushed
    -i hope you still understand it though
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    (Original post by wndms)
    Can soneone help me with this? I have no idea how to do this question... like No idea!!!!!

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    I (tried to) explain this to someone yesterday.
    I attached a drawing of my cycle on page 27, its the last post on that page
    basically the cycle doesnt look like a normal hess's law one, but the principles are the same.
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    (Original post by wndms)
    Can soneone help me with this? I have no idea how to do this question... like No idea!!!!!

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    It's: 193 - 111

    = +82
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    Anyone up for revision questions
    Why can tertiary alcohols be oxidised
    Problems of high concentrations of CO and NO
    Define elctrophile
    Conditions for fermentation
    Describe conditions for productions of Magerine
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    (Original post by needtosucceed=))
    I (tried to) explain this to someone yesterday.
    I attached a drawing of my cycle on page 27, its the last post on that page
    basically the cycle doesnt look like a normal hess's law one, but the principles are the same.
    Oh I think I get it. So you added Carbon for both sides right? But for N2 + 0.5O2 bit, I understand Carbon + oxygen = CO hence you right at the bottom.. but then N2 + C doesn't make sense?! (Is that why you ignored it?)

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    (Original post by niceguy95)
    Anyone up for revision questions
    Why can tertiary alcohols be oxidised
    Assume you mean CANT be oxidised because the carbon with OH on it has 3 other R groups on it



    Problems of high concentrations of CO and NO
    not really sure what the questions means...
    Define elctrophile
    electron pair acceptor
    Conditions for fermentation yeast and 37 degrees
    Describe conditions for productions of Magerinedon't remember this.. is it on the spec
    Answers in bold
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    (Original post by wndms)
    Oh I think I get it. So you added Carbon for both sides right? But for N2 + 0.5O2 bit, I understand Carbon + oxygen = CO hence you right at the bottom.. but then N2 + C doesn't make sense?! (Is that why you ignored it?)

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    not exactly. basically, what you do is look at ur overall equation, then draw arrows down with the corresponding equations given in that table. so, for the reactants, the corresponding equation would be the c+0.5o2=co ( just look at which one has the same reactants/at least one reactant is the same) so for the product n2o, the arrow coming down must be for the equation c+n20=co + n2. does that make more sense? it doesnt really matter what products you get after you've drawn the arrow, the main thing is that you've got the numbers in the right places
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    (Original post by t()m)
    Answers in bold
    For co it was toxic and no can cause acid rain

    For magerine it's the hydrogenation reaction using hydrogen in 150c and nickel catalyst

    Fr year include anaerobic conditions
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    (Original post by needtosucceed=))
    not exactly. basically, what you do is look at ur overall equation, then draw arrows down with the corresponding equations given in that table. so, for the reactants, the corresponding equation would be the c+0.5o2=co ( just look at which one has the same reactants/at least one reactant is the same) so for the product n2o, the arrow coming down must be for the equation c+n20=co + n2. does that make more sense? it doesnt really matter what products you get after you've drawn the arrow, the main thing is that you've got the numbers in the right places
    Could you be kind enough to draw it out, as I was was struggling at that kind of question as well


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    (Original post by Jimmy20002012)
    Could you be kind enough to draw it out, as I was was struggling at that kind of question as well


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    i've done it already, page 27 last post ive attached it
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    (Original post by niceguy95)
    For co it was toxic and no can cause acid rain

    For magerine it's the hydrogenation reaction using hydrogen in 150c and nickel catalyst

    Fr year include anaerobic conditions
    ok

    Define hydrolysis?
    Compare rate of reaction of halogenalkane hydrolysis?
    whats the difference between structural isomers and sterioisomers?
    Whats the generic formula for a cycloalkene ?
    Whats the prefix for a 9 carbon side chain?
    How are alkenes formed?
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    (Original post by niceguy95)
    Anyone up for revision questions
    Why can tertiary alcohols be oxidised
    Problems of high concentrations of CO and NO
    Define elctrophile
    Conditions for fermentation
    Describe conditions for productions of Magerine
    - tertiary alcohols can't be oxidised
    - because for oxidation to occur there must be a Hydrogen on the carbon that is attached to the OH group
    - this is because the C-H bond is broken during oxidation

    Problems with CO:
    - toxic / poisonous
    - reduces the O2 carrying capacity in blood

    Problems with NO:
    - acid rain
    - formation of low level ozone
    - photochemical smog
    - irritants in animals

    Electrophile:
    - electron pair acceptor

    Fermentation of sugars ie glucose:
    - anaerobic
    - yeast
    - 37 degrees


    Making margarine:
    - unsaturated of vegetable oils
    - using Ni catalyst
    - 150 degrees

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    (Original post by t()m)
    ok

    Define hydrolysis?
    Compare rate of reaction of halogenalkane hydrolysis?
    whats the difference between structural isomers and sterioisomers?
    Whats the generic formula for a cycloalkene ?
    Whats the prefix for a 9 carbon side chain?
    How are alkenes formed?
    Hydrolysis:
    - breaking of bonds (compounds)
    - upon addition of water

    Halagenoalkanes:
    - as you go down group 7 bond Enthalpy decreases
    - C-I bonds break easily/fastest
    - this is because they are shorter
    Etc

    Structural isomer:
    - compounds that have the same molecular formula
    - but have a different structural formula

    Stereoisomer:
    - compounds that have the same structural formula
    - but have a different 3D spatial arrangement

    Prefix ?? Is that just C9H20?

    How alkenes formed:
    - adjacent p orbitals overlap to form a Pi bond
    - then draw simple diagram with labels

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    (Original post by needtosucceed=))
    i've done it already, page 27 last post ive attached it
    Still don't get it, hate that question I cannot do Hess law cycles, my teacher only said you need to only know for combustion it's reactants - products and for formation you do Products - Reactants. Can out help me out please????


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    (Original post by needtosucceed=))
    not exactly. basically, what you do is look at ur overall equation, then draw arrows down with the corresponding equations given in that table. so, for the reactants, the corresponding equation would be the c+0.5o2=co ( just look at which one has the same reactants/at least one reactant is the same) so for the product n2o, the arrow coming down must be for the equation c+n20=co + n2. does that make more sense? it doesnt really matter what products you get after you've drawn the arrow, the main thing is that you've got the numbers in the right places
    Yeah it does now. Thank you!

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    (Original post by Jimmy20002012)
    Still don't get it, hate that question I cannot do Hess law cycles, my teacher only said you need to only know for combustion it's reactants - products and for formation you do Products - Reactants. Can out help me out please????


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    Yup that's all you need to know. Easy 3 marks always!
 
 
 
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