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    Having done the paper on thurs I thought it was ok... having re-done and marked it, it was hardd! :-s lol... just managed to get 60/80... and being harsh marker hehehe
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    (Original post by pingu09)
    Having done the paper on thurs I thought it was ok... having re-done and marked it, it was hardd! :-s lol... just managed to get 60/80... and being harsh marker hehehe
    That'll probably get you a high A. Well done! :yes:
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    when do we find the official grade boundries are they shown in the edexcel website any time soon??
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    Yup. With harsh marking I counted it up to be about 63. Thats a low A using last grade boundaries. I'll take an "A" in any shape or size!
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    (Original post by moh2009)
    Yup. With harsh marking I counted it up to be about 63. Thats a low A using last grade boundaries. I'll take an "A" in any shape or size!
    lol... totallyy agree... an A in any shape or sizee!
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    (Original post by Narik)
    That'll probably get you a high A. Well done! :yes:
    hopee sooo!.. going to do unit 2 along with the A2 units in june so really need this one to be off my back.
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    (Original post by pingu09)
    hopee sooo!.. going to do unit 2 along with the A2 units in june so really need this one to be off my back.
    Unit 2 with A2 Units? Wow man. I could never do that unless I had no choice, any particular reason you're doing it in summer instead of January? Mines next Thursday.
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    who has the paper that was done? and has scanned it to upload or even just have the multiple choice answers?
    this would be very helpful!
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    omg omg omg i just realized that i didnt see the part saying "the remainder is oxygen" in the sulfumic acid thing! oh no no no !!!! 4 marks gone!! :'(
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    The answer to question 5 is A. If you read the question they ask which reaction show the mean enthalp[y change for a C-H bond. The enthalpy change for reaction C will show the enthalpy of 4 H bonds, and would need dividing by four, which has been done already in A.
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    (Original post by Monkeyy)
    Shouldn't it be C! Since the highest ionization energy is the I.E of a noble gas, which is B, and the proceeding one is a group 1 element. :O
    Yep that would be the case if they were asking for the first IE but they are asking for the second.
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    (Original post by Teacherman)
    The answer to question 5 is A. If you read the question they ask which reaction show the mean enthalp[y change for a C-H bond. The enthalpy change for reaction C will show the enthalpy of 4 H bonds, and would need dividing by four, which has been done already in A.
    http://www.webchem.net/notes/how_far...y_diagrams.htm

    It is: CH4 --> C + 4H
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    (Original post by Narik)
    http://www.webchem.net/notes/how_far...y_diagrams.htm

    It is: CH4 --> C + 4H
    LOL. After the posts on here last night I thought I'd got that wrong. But thankss dude. Given me a great start to the day lol.
    Ach. Back to Physics noww... :p:
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    (Original post by Narik)
    http://www.webchem.net/notes/how_far...y_diagrams.htm

    It is: CH4 --> C + 4H
    The answer is A

    not that ...

    Read the question CAREFULLY...

    it says which of the following reactions will give a value for the mean bond enthalpy of the C-H bond....

    CH4 --> C + 4H
    the enthalpy of reaction is like +1612 kJ/ mol
    WHICH IS NOT the mean bond enthalpy of the C-H bond...
    :eek3:
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    (Original post by killfestab)
    exactly...

    Section A
    Question 7 has to be C ... i thought long and hard because they tried to trick us with second ionization energy... but obviously, if you are comparing the second ionization energies of all elements, it has to be the same :/

    and i think question 5 section A
    should be A
    because the question asks "the mean bond enthalpy"
    Yes indeed!! No matter what number of Ionization energies it is, it will be the same! About question 5, I'm not really sure about that :/
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    (Original post by killfestab)
    The answer is A

    not that ...

    Read the question CAREFULLY...

    it says which of the following reactions will give a value for the mean bond enthalpy of the C-H bond....

    CH4 --> C + 4H
    the enthalpy of reaction is like +1612 kJ/ mol
    WHICH IS NOT the mean bond enthalpy of the C-H bond...
    :eek3:
    No you are wrong. You work out the mean bond enthalpy using that equation. This is because you can't have H2, since you'd need energy to break the hydrogen molecule into hydrogen atoms and then bond it with the carbon. It has to be: CH4 --> C + 4H, because this is the reaction you use to work out the MEAN bond enthalpy, since you work out the total energy and then you divide by 4.

    It's not that hard to understand you know.
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    (Original post by Monkeyy)
    Yes indeed!! No matter what number of Ionization energies it is, it will be the same! About question 5, I'm not really sure about that :/
    I'm sorry, but I'm pretty certain you're wrong. This is because, the pattern of the ionisation energies change when you're talking about the second ionisation energy. This is because of the existence of subshells and different energy levels [i.e. principle quantum number]. This means that the pattern will not be the same.

    Lithium has the highest SECOND ionisation energy because you need A LOT of energy to remove a second electron from its 1s2 subshell because it is complete.

    Hope I made myself clear. :yes:
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    (Original post by Narik)
    I'm sorry, but I'm pretty certain you're wrong. This is because, the pattern of the ionisation energies change when you're talking about the second ionisation energy. This is because of the existence of subshells and different energy levels [i.e. principle quantum number]. This means that the pattern will not be the same.

    Lithium has the highest SECOND ionisation energy because you need A LOT of energy to remove a second electron from its 1s2 subshell because it is complete.

    Hope I made myself clear. :yes:
    But when you remove an electron from any subshell, the Ionisation energy becomes higher, right?
    Why is it, when you remove a second electron, Lithium suddenly has the highest I.E??? But.... I don't know... Maybe you're right, maybe I am...
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    (Original post by Monkeyy)
    But when you remove an electron from any subshell, the Ionisation energy becomes higher, right?
    Why is it, when you remove a second electron, Lithium suddenly has the highest I.E??? But.... I don't know... Maybe you're right, maybe I am...

    Narik is right. Its closer to the nucleus more energy is required to remove it cos of increased attraction. Etc etc.
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    ehhh....
 
 
 
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