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***2013 LC Chemistry Before/After***

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12467…33

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    #92
    weirdspider
    Registered Users Posts: 346 ✭✭weirdspider


    SecondMan wrote: »
    Me

    Jaysus JJ you've lived a lengthy life!


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    #93
    Hamza Malik
    Registered Users Posts: 161 ✭✭Hamza Malik


    In relation to recrystalisation of benzoic acid..

    Why is it important to use the the least amount of hot solvent at crystallisation stage ?

    What would you do if crystals formed on the filter paper?


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    #94
    outnumbered
    Closed Accounts Posts: 1,696 ✭✭✭outnumbered


    Hamza Malik wrote: »
    In relation to recrystalisation of benzoic acid..

    Why is it important to use the the least amount of hot solvent at crystallisation stage ?

    What would you do if crystals formed on the filter paper?

    To maximise the amount precipitating out
    Scrape them off?


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    #95
    ladymacbeth
    Registered Users Posts: 64 ✭✭ladymacbeth


    Hoping for the Iron Tablet experiment as question 1 and a lovely Organic Experiment in question 3. If there was a decent question 3, i would have less to do in section 2 - ideally!


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    #96
    Acciaccatura
    Registered Users Posts: 428 ✭✭Acciaccatura


    The definition video is now on its way, I only got time to do 11 though, and I stress what I said earlier about my singing. Stay tuned :P


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    #97
    Slow Show
    Registered Users Posts: 4,248 ✭✭✭Slow Show


    outnumbered wrote: »
    To maximise the amount precipitating out
    Scrape them off?

    I think a more precise answer would be to ensure the solution is saturated as with too much solvent, the solution would be too dilute for crystals to form.

    As for the second question there, err I dunno really, I know you use the Buchner apparatus with the suction pump to minimise the possibility of that happening, as for those that would form I'd just get rid of them and forget they ever happened. :L


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    #98
    woopah92
    Registered Users Posts: 482 ✭✭woopah92


    Acciaccatura wrote: »
    The definition video is now on its way, I only got time to do 11 though, and I stress what I said earlier about my singing. Stay tuned :P

    What song are the defintions sung to?


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    #99
    Parawhore.xD
    Registered Users Posts: 571 ✭✭✭Parawhore.xD


    Slow Show wrote: »
    I think a more precise answer would be to ensure the solution is saturated as with too much solvent, the solution would be too dilute for crystals to form.

    As for the second question there, err I dunno really, I know you use the Buchner apparatus with the suction pump to minimise the possibility of that happening, as for those that would form I'd just get rid of them and forget they ever happened. :L

    I was told to pour hot water on the filter paper to allow them to redissolve and filter through I think?


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    #100
    Acciaccatura
    Registered Users Posts: 428 ✭✭Acciaccatura


    woopah92 wrote: »
    What song are the defintions sung to?

    Lots of different ones, everything from Lady Gaga to Mozart :pac: Gimme another 10 minutes and I'll show you :P


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    #101
    Acciaccatura
    Registered Users Posts: 428 ✭✭Acciaccatura


    Here it is! I'm not gonna lie, I am quite embarrassed about this :pac: I'll just leave all my shame with this post :P




    NB: Mods should note that I'm not a regular Youtuber looking for attention and subscribers. I'm far too mediocre for that crap :P


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    #102
    outnumbered
    Closed Accounts Posts: 1,696 ✭✭✭outnumbered


    Acciaccatura wrote: »
    Here it is! I'm not gonna lie, I am quite embarrassed about this :pac: I'll just leave all my shame with this post :P




    NB: Mods should note that I'm not a regular Youtuber looking for attention and subscribers. I'm far too mediocre for that crap :P

    Sin absolutely ar fheabhas!!!!!!!!!!
    Take a Bow!!
    How did you come up with this?


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    #103
    Hamza Malik
    Registered Users Posts: 161 ✭✭Hamza Malik


    The aufbau principle was very good :o


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    #104
    Acciaccatura
    Registered Users Posts: 428 ✭✭Acciaccatura


    outnumbered wrote: »
    Sin absolutely ar fheabhas!!!!!!!!!!
    Take a Bow!!
    How did you come up with this?

    I had waaay too much time on my hands during 5th year, you'd think I'd had nothing better to do :rolleyes: But thank you, hope it's useful now :o


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    #105
    outnumbered
    Closed Accounts Posts: 1,696 ✭✭✭outnumbered


    Acciaccatura wrote: »
    I had waaay too much time on my hands during 5th year, you'd think I'd had nothing better to do :rolleyes: But thank you, hope it's useful now :o

    Cool! Well you will remember them anyway! :D
    Thank you!


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    #106
    Acciaccatura
    Registered Users Posts: 428 ✭✭Acciaccatura


    outnumbered wrote: »
    Cool! Well you will remember them anyway! :D
    Thank you!

    I've gone all shy now :o:p You're very welcome! :D


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    #107
    outnumbered
    Closed Accounts Posts: 1,696 ✭✭✭outnumbered


    Acciaccatura wrote: »
    I've gone all shy now :o:p You're very welcome! :D

    Don't be! An obvious genious and an excellent singer! Nothing to be shy about.
    By the way, some reason on the Med forum I always thought you were a boy? haha. HPAT results soon? :/


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    #108
    Acciaccatura
    Registered Users Posts: 428 ✭✭Acciaccatura


    outnumbered wrote: »
    Don't be! An obvious genious and an excellent singer! Nothing to be shy about.
    By the way, some reason on the Med forum I always thought you were a boy? haha. HPAT results soon? :/

    Ah that's pushing it now :p Last time I checked, I'd no Y chromosomes anyway :pac: Don't be worried about the HPAT, just enjoy the break between chemistry and the 24th and you can get as psyched up in the morning as you want. You'll be FINE, I've seen some of your posts, you're a hard worker, you'll have this medicine in that bag :)


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    #109
    Scuid Mhór
    Registered Users Posts: 2,326 ✭✭✭Scuid Mhór


    Acciaccatura wrote: »
    Here it is! I'm not gonna lie, I am quite embarrassed about this :pac: I'll just leave all my shame with this post :P




    NB: Mods should note that I'm not a regular Youtuber looking for attention and subscribers. I'm far too mediocre for that crap :P

    Marry me?!


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    #110
    outnumbered
    Closed Accounts Posts: 1,696 ✭✭✭outnumbered


    Acciaccatura wrote: »
    Ah that's pushing it now :p Last time I checked, I'd no Y chromosomes anyway :pac: Don't be worried about the HPAT, just enjoy the break between chemistry and the 24th and you can get as psyched up in the morning as you want. You'll be FINE, I've seen some of your posts, you're a hard worker, you'll have this medicine in that bag :)

    No it's not! :)
    haha sorry, don't know why I thought that? :P what's your name mean anyway?
    Ah I suppose, it's just i know I did crap! Hah, I do work hard, but sometimes for Med that's not enough. I'm sure you'll get it too! Where's your first choice?


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    #111
    outnumbered
    Closed Accounts Posts: 1,696 ✭✭✭outnumbered


    Scuid Mhór wrote: »
    Marry me?!

    Back off, she's mine!


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    #112
    Acciaccatura
    Registered Users Posts: 428 ✭✭Acciaccatura


    outnumbered wrote: »
    Back off, she's mine!

    Form an orderly queue now :P

    Ehm, I've UCD down first because I'd like to do the premed and I just felt I'd have liked it better than Trinity. If I get medicine at all, I'd say it'll be by some miracle, like third round offers, to Galway :pac: Where are you hoping to go?


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    #113
    outnumbered
    Closed Accounts Posts: 1,696 ✭✭✭outnumbered


    Acciaccatura wrote: »
    Form an orderly queue now :P

    Ehm, I've UCD down first because I'd like to do the premed and I just felt I'd have liked it better than Trinity. If I get medicine at all, I'd say it'll be by some miracle, like third round offers, to Galway :pac: Where are you hoping to go?
    hehe
    Ah UCD looks amazing! Well, I'm the same as you in that it will be a miracle if I get it! I applied to that HEAR but it's really unlikely I will get that, and even with that I MAY have a slim chance for NUIG!
    So, if you don't get it what's your plans?


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    #114
    MarieCurie22
    Registered Users Posts: 204 ✭✭MarieCurie22


    Predictions:
    Many of these predictions have come from different teachers who all said the same thing so they are likely however they are only predictions...

    Q1. BOD of water or % bleach or % iron in iron tablets. My guess is BOD.
    Q2. Ethanoic Acid or Ethanal. Definitely one of these two id put my money on ethanoic acid it's off the course next year.
    Q3. The affect of temp on rate of reaction or Decomposition of H2O2 by MnO2

    For question 5:
    -Bohrs theory and its limitations and or ionisation energy.

    Other tips....
    -Equilibrium with experiments to show Le Chateliers principle.
    -Octane number and fuels (obviously thats always there)
    -Radioactivity

    I would really go over organic as so little came up last year it could be all over the paper this year...especially as the guy who sets the papers is an organic chemist!


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    #115
    Acciaccatura
    Registered Users Posts: 428 ✭✭Acciaccatura


    outnumbered wrote: »
    hehe
    Ah UCD looks amazing! Well, I'm the same as you in that it will be a miracle if I get it! I applied to that HEAR but it's really unlikely I will get that, and even with that I MAY have a slim chance for NUIG!
    So, if you don't get it what's your plans?

    Ah I'm sure you'll get medicine :) I've pharmacy and physio down in a few places, but I've that nice BBB science course in UCD down too, and #10 is science in Galway for 380 points. If I don't get that I'm outta here! :pac:

    Oh, btw, my name is a music reference, it's a little note you sometimes see on a music score that you just sort of flick off really quick, also called a grace note. I chose it cos I'm small and it's a cool word :P


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    #116
    MarieCurie22
    Registered Users Posts: 204 ✭✭MarieCurie22


    Hamza Malik wrote: »
    In relation to recrystalisation of benzoic acid..

    Why is it important to use the the least amount of hot solvent at crystallisation stage ?

    What would you do if crystals formed on the filter paper?

    -To maimise yield of Benzoic acid.
    -Rinse through with hot water.


  • Options
    #117
    outnumbered
    Closed Accounts Posts: 1,696 ✭✭✭outnumbered


    Acciaccatura wrote: »
    Ah I'm sure you'll get medicine :) I've pharmacy and physio down in a few places, but I've that nice BBB science course in UCD down too, and #10 is science in Galway for 380 points. If I don't get that I'm outta here! :pac:

    Oh, btw, my name is a music, it's a little note you sometimes see on a music score that you just sort of flick off really quick, also called a grace note. I chose it cos I'm small and it's a cool word :P

    I hope so! :) Ah similar to mine. I have the 2 dublin Pharmacy down but i think i'd find it boring! What BBB course?
    Ah cool, you learn something everyday! This week, just a whole lot more! :P


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    #118
    yoppo
    Registered Users Posts: 206 ✭✭yoppo


    MarieCurie22 wrote: »
    Predictions:
    Many of these predictions have come from different teachers who all said the same thing so they are likely however they are only predictions...

    Q1. BOD of water or % bleach or % iron in iron tablets. My guess is BOD.
    Q2. Ethanoic Acid or Ethanal. Definitely one of these two id put my money on ethanoic acid it's off the course next year.
    Q3. The affect of temp on rate of reaction or Decomposition of H2O2 by MnO2

    For question 5:
    -Bohrs theory and its limitations and or ionisation energy.

    Other tips....
    -Equilibrium with experiments to show Le Chateliers principle.
    -Octane number and fuels (obviously thats always there)
    -Radioactivity

    I would really go over organic as so little came up last year it could be all over the paper this year...especially as the guy who sets the papers is an organic chemist!

    Oh I love organic :pac:

    Done my degree in chemistry specialising in organic

    Roll on the 18th!
    :cool:


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    #119
    MarieCurie22
    Registered Users Posts: 204 ✭✭MarieCurie22


    Prodigious wrote: »
    Mocks are bull****.

    What are the three stresses which LCP applies to?

    It is to provide H+ ions but you have to say WHY
    Becareful what they ask...
    if they ask why is it added to the iron tablets when grinding its 2 things:
    1-To aid the crushing of the hard shells.
    2-To prevents Fe+2 being oxidised by air and becoming Fe+3 there for sulfuric acid is needed.

    If they ask why was it added to the conical flask the answer is...
    To prevent The Mn+7 from becoming Mn+4 which is brown, we want it to be fully reduced to Mn+2 therefore we need H+ ions from the sulfuric acid!


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    #120
    Acciaccatura
    Registered Users Posts: 428 ✭✭Acciaccatura


    outnumbered wrote: »
    I hope so! :) Ah similar to mine. I have the 2 dublin Pharmacy down but i think i'd find it boring! What BBB course?
    Ah cool, you learn something everyday! This week, just a whole lot more! :P

    It's just general science in UCD, but you can specialise in biology, chemistry or physics, it's DN200 :) Oh yeah, the amount of unrelated stuff I've learned this month, for example how to mimic a bird call a la spy movies, is impressive :pac:


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    #121
    Hamza Malik
    Registered Users Posts: 161 ✭✭Hamza Malik


    MarieCurie22 wrote: »
    It is to provide H+ ions but you have to say WHY
    Becareful what they ask...
    if they ask why is it added to the iron tablets when grinding its 2 things:
    1-To aid the crushing of the hard shells.
    2-To prevents Fe+2 being oxidised by air and becoming Fe+3 there for sulfuric acid is needed.

    If they ask why was it added to the conical flask the answer is...
    To prevent The Mn+7 from becoming Mn+4 which is brown, we want it to be fully reduced to Mn+2 therefore we need H+ ions from the sulfuric acid!

    So they are looking for two things.

    To supply H+ ions so the Mn7 is reduced to Mn2 ?

    I really need a B1 for chemistry :/


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