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****Leaving Certificate Chemistry [All Levels] Before and After Discussion****

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13567…13

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    #62
    rocco123
    Registered Users Posts: 7 ✭rocco123


    Wanderer41 wrote: »
    Thanks a million, I really appreciate it :)



    I think it says in the marking schemes that other answers are acceptable if they are correct, as in not all answers are listed. However I think for definitions especially you have to have the bold text.

    Yeah I suppose, but say for a question on rates of reaction on one of recent years, making schemes more collisions are effective if I say more effective collisions will I get the marks?


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    #63
    MacBizzle
    Closed Accounts Posts: 913 ✭✭✭MacBizzle


    Anyone else want the DEB paper?


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    #64
    Wanderer41
    Registered Users Posts: 240 ✭✭Wanderer41


    rocco123 wrote: »
    Yeah I suppose, but say for a question on rates of reaction on one of recent years, making schemes more collisions are effective if I say more effective collisions will I get the marks?

    I expect so, yes. Try not to worry about it. If you have the correct answer you will get the marks. At the beginning of the marking scheme it says that the answers provided are not the only answers acceptable. Just be careful for definitions but your example about rates should be fine.


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    #65
    Murky013
    Registered Users Posts: 7 ✭Murky013


    For exp, it's either %water of crystallization, iron tablets or vinegar titration.

    For organic its either ethylene, ethanal or ethanoic acid one

    That's my gut feeling imho


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    #66
    little sis...
    Registered Users Posts: 910 ✭✭✭little sis...


    I was feeling ok about chemistry before I read some of the posts here o_O
    Murky013 wrote: »
    For exp, it's either %water of crystallization, iron tablets or vinegar titration.

    For organic its either ethylene, ethanal or ethanoic acid one

    That's my gut feeling imho

    Ethylene?


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    #67
    Murky013
    Registered Users Posts: 7 ✭Murky013


    little sis... wrote: »
    Ethylene?

    Sorry I meant ethyne. Feckin' autocorrect. :P


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    #68
    marno21
    Moderators, Entertainment Moderators, Science, Health & Environment Moderators Posts: 14,389 Mod ✭✭✭✭marno21


    World Cup 2 - 0 Chemistry study :/

    What I meant abotu the biology is the biology paper was different to all the other years this year. None of the usual topics and strong emphasis on lesser stuff.

    Imagine a paper this year with no atomic theory as q5 etc. :/ (sorry for scaring some of ye)


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    #69
    MacBizzle
    Closed Accounts Posts: 913 ✭✭✭MacBizzle


    marno21 wrote: »
    World Cup 2 - 0 Chemistry study :/

    What I meant abotu the biology is the biology paper was different to all the other years this year. None of the usual topics and strong emphasis on lesser stuff.

    Imagine a paper this year with no atomic theory as q5 etc. :/ (sorry for scaring some of ye)

    Please stop.


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    #70
    little sis...
    Registered Users Posts: 910 ✭✭✭little sis...


    Why does everyone think it will all go wrong THIS year?
    Who cares if another person is setting it? It's hardly going to have some dramatically different layout and question types.
    Why don't we all get excited about the fact it may well be a lovely paper :D


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    #71
    marno21
    Moderators, Entertainment Moderators, Science, Health & Environment Moderators Posts: 14,389 Mod ✭✭✭✭marno21


    My apologies for the negativity :p

    I won't say what I was going to say next

    Easy experiment questions, 3 atomic theory, 2 fuels + heats of reaction + 2 water anyone? :D


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    #72
    accountname
    Registered Users Posts: 95 ✭✭accountname


    MacBizzle wrote: »
    Anyone else want the DEB paper?

    If you don't mind? :rolleyes:


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    #73
    WoolyAbyss
    Registered Users Posts: 98 ✭✭WoolyAbyss


    Do we need to know the diagrams for the organic experiments or do they always give them?
    The ethanal and ethanoic acid ones would be horrible to draw.


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    #74
    Soapndglory
    Registered Users Posts: 2 ✭Soapndglory


    WoolyAbyss wrote: »
    Do we need to know the diagrams for the organic experiments or do they always give them?
    The ethanal and ethanoic acid ones would be horrible to draw.

    Yes you have to be able to draw all the apparatus cus they can ask on it and it'll be worth a fair few marks! My teacher has drilled us to be able to draw them in under 4 minutes!!


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    #75
    plmko
    Registered Users Posts: 160 ✭✭plmko


    Could anyone explain the heat of neutralisation experiment with HCl and NaOH please? I know it came up last year but just incase it appears in Section B.

    What's the timing for Chemistry? Twenty mins per question or..?


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    #76
    MacBizzle
    Closed Accounts Posts: 913 ✭✭✭MacBizzle


    plmko wrote: »
    What's the timing for Chemistry? Twenty mins per question or..?

    22 and a half minutes per question if you want to get 8 done.

    20 per question and you'll get 9 done, which I'll be doing because I'm bound to mess up one question :p


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    #77
    accountname
    Registered Users Posts: 95 ✭✭accountname


    plmko wrote: »
    What's the timing for Chemistry? Twenty mins per question or..?

    22 mins per question. You'll probably find you get them done quicker than this, so you should have plenty of time for an extra question :)

    For the HCl and NaOH, just know the formula for it and the units you have to convert the figures to. If they ask it in Section B I'd only see them asking a calculation for it


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    #78
    plmko
    Registered Users Posts: 160 ✭✭plmko


    accountname wrote: »
    For the HCl and NaOH, just know the formula for it and the units you have to convert the figures to. If they ask it in Section B I'd only see them asking a calculation for it

    Thanks! And how do you do the calculations?


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    #79
    accountname
    Registered Users Posts: 95 ✭✭accountname


    plmko wrote: »
    Thanks! And how do you do the calculations?

    Formula is; heat= m * c * (t2-t1)
    where m = mass in kg
    c= specific heat capacity of solution given in the question
    and t2-t1 is the difference in the temperatures
    Just sub in all them and you'll get your heat in kJ/mol

    'Tis a dirty calculation but as you said, it came up last year so I wouldn't worry too much about it :P


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    #80
    EoghanIRL
    Registered Users Posts: 4,080 ✭✭✭EoghanIRL


    accountname wrote: »
    Formula is; heat= m * c * (t2-t1)
    where m = mass in kg
    c= specific heat capacity of solution given in the question
    and t2-t1 is the difference in the temperatures
    Just sub in all them and you'll get your heat in kJ/mol

    'Tis a dirty calculation but as you said, it came up last year so I wouldn't worry too much about it :P

    It was on pre for heats of reaction question . If you do physics then the mc delta t thing is so easy:P


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    #81
    MacBizzle
    Closed Accounts Posts: 913 ✭✭✭MacBizzle


    Are potassium iodate and potassium iodide the same thing? :confused:


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    #82
    Ompala
    Registered Users Posts: 905 ✭✭✭Ompala


    MacBizzle wrote: »
    Are potassium iodate and potassium iodide the same thing? :confused:

    Nope, Potassium Iodate is KI03 while potassium iodide is KI.
    -ate is used in the naming of things that contain oxygen e.g iron sulfate FeSO4


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    #83
    MacBizzle
    Closed Accounts Posts: 913 ✭✭✭MacBizzle


    Ompala wrote: »
    Nope, Potassium Iodate is KI03 while potassium iodide is KI.
    -ate is used in the naming of things that contain oxygen e.g iron sulfate FeSO4

    Think we must have skipped an experiment so, or else I just wasn't listening... :rolleyes:


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    #84
    Ompala
    Registered Users Posts: 905 ✭✭✭Ompala


    MacBizzle wrote: »
    Think we must have skipped an experiment so, or else I just wasn't listening... :rolleyes:

    Off the top of my head, isn't potassium iodide used in the winkler method for determining dissolved oxygen?


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    #85
    MacBizzle
    Closed Accounts Posts: 913 ✭✭✭MacBizzle


    Ompala wrote: »
    Off the top of my head, isn't potassium iodide used in the winkler method for determining dissolved oxygen?

    Yep, alkaline KI and manganese sulfate I think :p


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    #86
    JDOC1996
    Registered Users Posts: 445 ✭✭JDOC1996


    Predictions ?


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    #87
    MacBizzle
    Closed Accounts Posts: 913 ✭✭✭MacBizzle


    JDOC1996 wrote: »
    Predictions ?

    What can we really predict? Chemistry doesn't change much, all I've heard is soap being tipped, and the Hach test kit.


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    #88
    wafture
    Registered Users Posts: 17 ✭wafture


    Hach test kit?


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    #89
    MacBizzle
    Closed Accounts Posts: 913 ✭✭✭MacBizzle


    wafture wrote: »
    Hach test kit?

    You might have done the colorimeter, it's the free chlorine experiment in the water chapter.


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    #90
    TooMuchStudy
    Registered Users Posts: 82 ✭✭TooMuchStudy


    What are the chances of a gas question coming up this year?


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    #91
    MacBizzle
    Closed Accounts Posts: 913 ✭✭✭MacBizzle


    TooMuchStudy wrote: »
    What are the chances of a gas question coming up this year?

    Don't they come up every year in some shape or form?


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