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

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    Hard A= 72
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    It was okay A= 76
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    Easy A= 79
    75
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    Very Easy A=82
    60
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    (Original post by needtosucceed=))
    thats the rule for working out any empirical formula with .5
    How many post have made this thread btw, must be 300+
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    Guys i need help on question 6 c i June 2010

    It's only a marker and i don't know..

    THANKS

    Apparently., many ppl at my college are saying that the paper is goin to be harder... coz Jan was easy SCARING MEEE ..
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    (Original post by needtosucceed=))
    sorry im just gonna butt in..

    - corrosive and toxic
    - toxic, reduces the ability of the blood to carry oxygen
    - forms photochemical smog and low level ozone
    - petrol additive, making esters, methylated spirits (i think?)


    define average bond enthalpy (2)
    why would the value for enthalpy change be different when using average bond enthalpy 1)
    why is international cooperation important (3)
    Great!

    - average energy required to break 1 mole of a given (covalent) bond,
    - in the molecules in its gaseous state

    - bond enthalpies may not be the same as average bond Enthalpy

    - all countries contribute towards pollution
    - allows world wide legislation to be made
    - allows protocols to be developed
    - scientists can provide evidence and warn risk to governments
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    (Original post by GeneralOJB)
    Why is A2 harder? What is harder about it? I'm debating about whether to drop chemistry or not. I don't need it for uni as I wanna do maths.
    Because AS chemistry is mostly recall questions, with a few applied questions that require you to apply your knowledge to unfamiliar scenarios, whereas A2 is mostly applied and less recall questions
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    (Original post by niceguy95)
    How many post have made this thread btw, must be 300+
    EXACTLY....
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    (Original post by needtosucceed=))
    the average enthalpy change when one mole of gaseous covalent bonds are broken
    the enthalpy change that occurs in the molar quantities expressed in a chemical equation under standard conditions
    298k and 1atm
    alkene - br2 would decolourise it, alkane - it would stay brown
    butan-1-ol + pentanoic acid. conc h2so4 + reflux. cba to write the equation lol
    more particles per unit volume therefore more successful/frequent collisions
    c=c, restricted rotation and each carbon bonded to 2 different atoms/groups of atoms
    Great answers! Say orange to colorless for decolourises
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    (Original post by TheFootyKing19)
    If anyone can be bothered, try these:

    Define average bond Enthalpy (2)
    Define standard Enthalpy change of reaction (2)
    State standard conditions (1)
    State the test and colour change for Alkane and Alkene (3)
    How can you make Butylpentanoate, state the conditions and give an equation (5)
    How does an increase in concentration increase the rate of reaction? (2)
    State two features of E/Z isomerism? (2)
    This is the enthalpy change when 1 mole of a gaseous non is broken.

    This is the enthalpy change of a reaction experienced in its molar quantities which are in standard conditions

    Standard conditions: 100Kpa of pressure, 298K of temperature and 1.0dm of concentration

    Orange to colourless,

    Not sure, but is it butan-1-ol and pentatonic acid? You need a acid catalyst such H2SO4. You need to heat. The equation would be CH2OHCH2CH2CH3 + CH3CH2CH2CH2COOH ------ CH3CH2CH2CH2COOCH2CH2CH2CH3 + H2O- this is probably totally wrong

    Increasing concentration means there are more particles per unit volume, do more frequency collision per second.

    Non rotation of Double bonds and each carbon atom has two different groups attached

    Are these right?



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    can somebody help me do question 3d on JUNE 2012 http://www.ocr.org.uk/Images/135164-...urces-june.pdf
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    (Original post by niceguy95)
    How many post have made this thread btw, must be 300+

    (Original post by Jacksgap)
    EXACTLY....
    LOL probably..I like to help
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    (Original post by needtosucceed=))
    sorry im just gonna butt in..

    - corrosive and toxic
    - toxic, reduces the ability of the blood to carry oxygen
    - forms photochemical smog and low level ozone
    - petrol additive, making esters, methylated spirits (i think?)


    define average bond enthalpy (2)
    why would the value for enthalpy change be different when using average bond enthalpy 1)
    why is international cooperation important (3)
    AVERAGE BOND ENTHALPY:
    "The enthalpy change where one mole of reactants within their gaseous, covalent bonds are broken."

    - would this be: "The average bond enthalpy will consider the bond averages for a larger range of molecules and not specified for specific bond with a specific molecule."

    I'll leave the international cooperation one for someone else...



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    (Original post by TheFootyKing19)
    If anyone can be bothered, try these:

    Define average bond Enthalpy (2)
    Define standard Enthalpy change of reaction (2)
    State standard conditions (1)
    State the test and colour change for Alkane and Alkene (3)
    How can you make Butylpentanoate, state the conditions and give an equation (5)
    How does an increase in concentration increase the rate of reaction? (2)
    State two features of E/Z isomerism? (2)
    The enthalpy change when 1 mol of any given type of bond is broken down by homolytic fission in its gaseous state

    The enthalpy change when a reaction occurs In molar quantities shown in the equation u der standard conditions with products and reactants in their standard states

    298 K and 1 atmosphere

    Bromine water, with alkane stays orange, but with Alkenes bromine water turns colourless due double bonds

    Add butanol and pentanpic acid in the prsence of heat under reflux using a strong acid and water is the other product

    It means molecules are closer together, so collisions more frequent and successful, so increase rate of reaction

    Restricted rotation of c=c and 2 different groups attached each carbon atom of c=c

    Check that please
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    (Original post by Joey952)
    can somebody help me do question 3d on JUNE 2012 http://www.ocr.org.uk/Images/135164-...urces-june.pdf
    work out the moles for each one then divide one by the other and x100

    ignore the tonnes just work in grams.
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    Has anyone got a business exam tomorrow too,out of interest btw ?


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    (Original post by niceguy95)
    The enthalpy change when 1 mol of any given type of bond is broken down by homolytic fission in its gaseous state

    The enthalpy change when a reaction occurs In molar quantities shown in the equation u der standard conditions with products and reactants in their standard states

    298 K and 1 atmosphere

    Bromine water, with alkane stays orange, but with Alkenes bromine water turns colourless due double bonds

    Add butanol and pentanpic acid in the prsence of heat under reflux using a strong acid and water is the other product

    It means molecules are closer together, so collisions more frequent and successful, so increase rate of reaction

    Restricted rotation of c=c and 2 different groups attached each carbon atom of c=c

    Check that please
    correct
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    (Original post by krishkmistry)
    Has anyone got a business exam tomorrow too,out of interest btw ?


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    yea im resitting unit 2 are u?
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    (Original post by willcoombes)
    Just read the questions really carefully and make sure you answer is exactly what the examiners want, it's so easy to leave something minor out and lose marks because of it! Don't forget your minuses in enthalpy change of combustion :P
    thankyou kind soul! I'll try, damn I really need a high A! >.<
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    (Original post by needtosucceed=))
    use the equation actual/theoretical x100

    ignore the tonnes, just use grams

    work out the moles of each one then divide one by the other.
    i do this but i never seem to get the 1.5 mols that the markscheme says!! gaaaaah!
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    (Original post by Ché.)
    AVERAGE BOND ENTHALPY:
    "The enthalpy change where one mole of reactants within their gaseous, covalent bonds are broken."

    - would this be: "The average bond enthalpy will consider the bond averages for a larger range of molecules and not specified for specific bond with a specific molecule."

    I'll leave the international cooperation one for someone else...



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    defintions right.
    thats correct, an easier way of saying it would be that bond enthalpy values arent the same as average bond enthalpy vaues
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    In terms of the full UMS cap conversion in F322, what will that exactly be?
    I know the grade boundaries are quite high, but just out of interest!?



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    (Original post by JimmyA*)
    To be honest if your good at maths you'll find it easy as most people struggle with Unit 5 as it's lots of calculations. It is harder but alot more interesting. If you dropped chemistry what would your subjects be?
    further maths in a year(as+a2) and physics a2. I'm doing extra maths modules too for 'additional further maths' lul
 
 
 
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