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    (Original post by KateSW)
    Okay here are some test qs for you guys to answer!
    -Define the enthalpy of combustion
    -What happens to a Boltzmann Distribution diagram with increased temp?
    -What does the molecular ion show in mass spec?

    1- Enthalpy change of combustion is the enthalphy change that occurs when one mol of a given substance reacts completely with oxygen under standard conditions (101kPa/1 atmosphere and 298K) with all products and reactants in their standard states.

    2- The peak lowers, and the curve flattens giving more molecules with energy above that of the activation energy.

    3- The molecular ion in mass spec shows the Mr of the compound/molecule. So allows you to work out the molecular formula once you've found the empirical formula, and it also allows you to work out fragment ions (which remember always have a + charge!)

    Here's one for you:
    How are scientists trying to reduce the effect of global warming?
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    (Original post by KateSW)
    Okay here are some test qs for you guys to answer!
    -Define the enthalpy of combustion
    -What happens to a Boltzmann Distribution diagram with increased temp?
    -What does the molecular ion show in mass spec?
    they are quiet easy questions exam alot harder
    molecular ion peak relative atomic mass
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    (Original post by Dave_Beeston)
    1- Enthalpy change of combustion is the enthalphy change that occurs when one mol of a given substance reacts completely with oxygen under standard conditions (101kPa/1 atmosphere and 298K) with all products and reactants in their standard states.

    2- The peak lowers, and the curve flattens giving more molecules with energy above that of the activation energy.

    3- The molecular ion in mass spec shows the Mr of the compound/molecule. So allows you to work out the molecular formula once you've found the empirical formula, and it also allows you to work out fragment ions (which remember always have a + charge!)

    Here's one for you:
    How are scientists trying to reduce the effect of global warming?
    CCS deep under oceans under sea beds, also use renewable sources of energy eg solar wind turbines
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    will sorting and recycling and incineration for energy count???
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    (Original post by Dave_Beeston)

    Here's one for you:
    How are scientists trying to reduce the effect of global warming?
    Well there is the Kyoto protocol so global warming is being monitored to establish more about it. Also trying to reduce carbon emissions through Carbon Capture Storage (Pumping it deep in the sea or into porous rocks etc.)

    EDIT: sorry I was a bit too late!!

    How do catalytic converters work, including an overall equation?
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    Hey guys what do you think the level of difficulty for this paper will be like....I've got predominantly A's in most practice papers but there have been one or two exceptions like the Jan 2010 and Jan 2011 paper in which I got solid B's....so do you think this paper will be a fairly standard paper based on previous years?
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    (Original post by asif123)
    Hey guys what do you think the level of difficulty for this paper will be like....I've got predominantly A's in most practice papers but there have been one or two exceptions like the Jan 2010 and Jan 2011 paper in which I got solid B's....so do you think this paper will be a fairly standard paper based on previous years?
    inshallah should be easy jan 11 was quiet easy
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    anyone else resitting F321 monday??
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    (Original post by shyro1000)
    anyone else resitting F321 monday??
    ME lol got b first time round wbu
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    (Original post by kingam)
    ME lol got b first time round wbu
    no lol i got a U, did shocking, even though i got A's and B's in the mock, i was so devastated. what are you focusing on?
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    (Original post by shyro1000)
    no lol i got a U, did shocking, even though i got A's and B's in the mock, i was so devastated. what are you focusing on?
    just past papers
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    (Original post by KateSW)
    How do catalytic converters work, including an overall equation?
    Nitrogen Oxides and Carbon Monoxide from the internal combustion engine are adsorbed on to the catalytic converter's palladium surface. The bonds between the molecules are then damaged by the catalyst, weakening them. This means that they have a lower activation energy. The molecules then react:

    2CO +2NO -> N2 + 2CO2

    The molecules of nitrogen and carbon dioxide are desorbed into the atmosphere.

    How are scientists trying to deal with polymers and CFCs?
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    (Original post by kingam)
    just past papers
    well good luck for monday
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    (Original post by shyro1000)
    well good luck for monday
    you too
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    (Original post by Dave_Beeston)

    How are scientists trying to deal with polymers and CFCs?
    Polymers can be combusted for energy, or melted and remoulded for other plastics.
    CFC's are being reduced (due to the Montreal protocol) and replaced by HFC's (which are much much slower at depleting the ozone)

    did I miss anything?

    What are the pros and cons of steam hydration over fermentation to produce ethanol?
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    (Original post by KateSW)

    What are the pros and cons of steam hydration over fermentation to produce ethanol?
    FERMENTATION:
    Advantages: the raw material is renewable, does not require oxygen, enzymes can be reused.

    Disadvantages: slow process, too much heat can cause enzyme to denature

    HYDRATION:
    Disadvantages: non-renewable raw material (crude oil), requires oxygen (steam)
    advantages: fast process
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    i was 1 mark of an A but my course is high so i didnt bother re sitting it because i only need alow B in f322 for an A overall wbu??
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    (Original post by akydon619)
    i was 1 mark of an A but my course is high so i didnt bother re sitting it because i only need alow B in f322 for an A overall wbu??
    how many marks did you get for CW
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    (Original post by shyro1000)
    FERMENTATION:
    Advantages: the raw material is renewable, does not require oxygen, enzymes can be reused.

    Disadvantages: slow process, too much heat can cause enzyme to denature

    HYDRATION:
    Disadvantages: non-renewable raw material (crude oil), requires oxygen (steam)
    advantages: fast process
    To be more precise, the enzyme in the yeast is zymase and the quoted temperature is around 37 C. The reaction is slow <25C and above 37C the enzyme denatures, losing its efficiency.

    May also be worth noting that another disadvantage of fermentation is that the enzyme ceases to function when the concentration (toxicity) of the ethanol is above 14/15%.

    I don't understand how the lack of oxygen is an advantage. Since fermentation is anaerobic, it is NECESSARY that there is an absence of oxygen, therefore money will need to be spent on suitable airtight apparatus. Otherwise, ethanol is oxidised to the aldehyde ethanal and then to the carboxylic acid, ethanoic acid. These undesirable compounds affect the flavour of the product.
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    you forgot to mention that hydration has a 100% atom economy while fermintation is less than 100% as it also produces CO2 as a waste product.
 
 
 
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