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**Chemistry...Before/After

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    #662
    Hayezer
    Registered Users Posts: 652 ✭✭✭Hayezer


    Whats volatile liquid that you used? I said propanone

    And there was question about pressure or something, cant remember it? What was answer :L?


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    #663
    finality
    Registered Users Posts: 1,763 ✭✭✭finality


    ei.sderob wrote: »
    I'm not sure if I saw the "to two decimal places"....I hope I have. This will eat away at me now!!!:P

    I can't remember if I did either. I usually leave things to 2 decimal places, sincerely hoping that question wasn't the one exception :L


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    #664
    abbeymate
    Registered Users Posts: 14 ✭abbeymate


    Sorry everyone, I thought that you were supposed to multiply by 2 because it was 500 cm^3 but that I forgot.. So I did divide by 2 because it was 2:1 and I got 0.1202 M/L for moles per litre and I multiplied 0.1202 by 36.5 (Mr of HCl) to get 4.3873 g/L.. How does that sound? And thanks everyone for your help!


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    #665
    Mista
    Registered Users Posts: 183 ✭✭Mista


    Hayezer wrote: »
    Whats volatile liquid that you used? I said propanone

    And there was question about pressure or something, cant remember it? What was answer :L?

    I used that too :D

    I think it was how do you know the pressure is the same as atmospheric pressure? I said something along the lines of excess pressure/vapour escapng though the pinhole :L


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    #666
    ei.sderob
    Closed Accounts Posts: 108 ✭✭ei.sderob


    finality wrote: »
    I can't remember if I did either. I usually leave things to 2 decimal places, sincerely hoping that question wasn't the one exception :L

    I hate how this site makes you doubt yourself!


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    #667
    leaveiton
    Closed Accounts Posts: 1,778 ✭✭✭leaveiton


    Right, from this thread I don't think I got a single calculation other than the heat of formation one right :pac: Ah well, didn't want those marks anyway.


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    #668
    finality
    Registered Users Posts: 1,763 ✭✭✭finality


    abbeymate wrote: »
    Sorry everyone, I thought that you were supposed to multiply by 2 because it was 500 cm^3 but that I forgot.. So I did divide by 2 because it was 2:1 and I got 0.1202 M/L for moles per litre and I multiplied 0.1202 by 36.5 (Mr of HCl) to get 4.3873 g/L.. How does that sound? And thanks everyone for your help!

    Pretty sure that's correct, though...it should've been to two decimal places :P
    Mista wrote: »
    I used that too :D

    I think it was how do you know the pressure is the same as atmospheric pressure? I said something along the lines of excess pressure/vapour escapng though the pinhole :L

    That's what I said too.


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    #669
    ei.sderob
    Closed Accounts Posts: 108 ✭✭ei.sderob


    abbeymate wrote: »
    Sorry everyone, I thought that you were supposed to multiply by 2 because it was 500 cm^3 but that I forgot.. So I did divide by 2 because it was 2:1 and I got 0.1202 M/L for moles per litre and I multiplied 0.1202 by 36.5 (Mr of HCl) to get 4.3873 g/L.. How does that sound? And thanks everyone for your help!

    Think that's right! I THINK.


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    #670
    kaet
    Registered Users Posts: 9 ✭kaet


    Sorry to bring it up again, but I don't think it was solved earlier and it's killing me.. For the equilibrium question did it have to be inverted or anything or was it just a really big Kc? I got 704.95 I think.


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    #671
    abbeymate
    Registered Users Posts: 14 ✭abbeymate


    finality wrote: »
    abbeymate wrote: »
    Sorry everyone, I thought that you were supposed to multiply by 2 because it was 500 cm^3 but that I forgot.. So I did divide by 2 because it was 2:1 and I got 0.1202 M/L for moles per litre and I multiplied 0.1202 by 36.5 (Mr of HCl) to get 4.3873 g/L.. How does that sound? And thanks everyone for your help!

    Pretty sure that's correct, though...it should've been to two decimal places :P

    CRAP CRAP CRAP!! Cant believe I got this far and to be deducted for such stupidity!! Wonder will they disallow my answers?? Please God let ne have a decent examiner!! ;-)


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    #672
    ShaunaMoll
    Registered Users Posts: 15 ✭ShaunaMoll


    Yellowstars wrote: »
    what did ye say for Q7 problems arising after adding too much of fluorin or chlorine(there the ones i chose). oh and q8 9(e) the reagent and catalyst to bring about conversion R. and the instantaneous rate at 60 seconds? :):D aaaand 4e.the oxidation/reduction balance?

    actually, for the oxidation/reduction balance, I just got a 2 in front of the H+ on the left hand side, seemed weird but I couldn't see another way?


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    #673
    Mista
    Registered Users Posts: 183 ✭✭Mista


    abbeymate wrote: »
    finality wrote: »

    Pretty sure that's correct, though...it should've been to two decimal places :P

    CRAP CRAP CRAP!! Cant believe I got this far and to be deducted for such stupidity!! Wonder will they disallow my answers?? Please God let ne have a decent examiner!! ;-)

    Nooo lol, you'll lose like 1 mark at most :P


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    #674
    finality
    Registered Users Posts: 1,763 ✭✭✭finality


    kaet wrote: »
    Sorry to bring it up again, but I don't think it was solved earlier and it's killing me.. For the equilibrium question did it have to be inverted or anything or was it just a really big Kc? I got 704.95 I think.

    That's what I got and so far I haven't been convinced that it's wrong or right. :L


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    #675
    RedTexan
    Registered Users Posts: 217 ✭✭RedTexan


    kaet wrote: »
    Sorry to bring it up again, but I don't think it was solved earlier and it's killing me.. For the equilibrium question did it have to be inverted or anything or was it just a really big Kc? I got 704.95 I think.
    why would it have to be inverted?


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    #676
    ShaunaMoll
    Registered Users Posts: 15 ✭ShaunaMoll


    kaet wrote: »
    Sorry to bring it up again, but I don't think it was solved earlier and it's killing me.. For the equilibrium question did it have to be inverted or anything or was it just a really big Kc? I got 704.95 I think.

    I got the same! I don't see why it'd have to be inverted? I've only ever inverted when it was a question where you were given KC and you had to use x's? This seemed like a straight forward equil. question. I'm really doubting myself now, arrrrgh!!


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    #677
    kyle84
    Registered Users Posts: 21 ✭kyle84


    id be so gutted if i didn't get my A1,i love chem so much. I was actually lookin forward to the exam. Questions 1 and 2 were ok,4 was grand,5,6,7 were very fun..i messed up rates-possibly the easiest question in everyone's opinion :L and i think i messed up sumtin in acids and bases,so overall it shud b ok.


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    #678
    finality
    Registered Users Posts: 1,763 ✭✭✭finality


    RedTexan wrote: »
    why would it have to be inverted?

    Some guy was saying that because the top arrow was pointing backwards you had to reverse the reaction and invert Kc. I disagree but he seemed quite adamant about it (and patronising).


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    #679
    ChemHickey
    Closed Accounts Posts: 3,479 ✭✭✭ChemHickey


    finality wrote: »
    Some guy was saying that because the top arrow was pointing backwards you had to reverse the reaction and invert Kc. I disagree but he seemed quite adamant about it (and patronising).


    The top arrow was pointing backwards?


    It's bloody equilibrium! :L Of course there are two arrows! :L


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    #680
    Rebels101
    Registered Users Posts: 4 ✭Rebels101


    would propan-1-ol and propan-2-ol be isomers aswell as propan=2=ol was alcohol a?


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    #681
    abbeymate
    Registered Users Posts: 14 ✭abbeymate


    Mista wrote: »
    abbeymate wrote: »
    finality wrote: »

    Pretty sure that's correct, though...it should've been to two decimal places :P

    CRAP CRAP CRAP!! Cant believe I got this far and to be deducted for such stupidity!! Wonder will they disallow my answers?? Please God let ne have a decent examiner!! ;-)

    Nooo lol, you'll lose like 1 mark at most :P

    Ok... Thanks everyone im gonna stop checking up all the answers now before it drives me insane!! Was hoping for an A1 but would be happy with an A2 now, so many silly little mistakes :'( :L


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    #682
    ShaunaMoll
    Registered Users Posts: 15 ✭ShaunaMoll


    finality wrote: »
    Some guy was saying that because the top arrow was pointing backwards you had to reverse the reaction and invert Kc. I disagree but he seemed quite adamant about it (and patronising).

    Ugh, that's the first time i've ever seen the top arrow pointing backwards! Would they really be that mean? Could be a missprint?...please let it be a missprint..


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    #683
    kyle84
    Registered Users Posts: 21 ✭kyle84


    i dont like equilibrium but the position of the arrows sounds fairly irrelevant. A value of 704 sounds very high but then again it seems to be popular so its prob right


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    #684
    finality
    Registered Users Posts: 1,763 ✭✭✭finality


    ChemHickey wrote: »
    The top arrow was pointing backwards?


    It's bloody equilibrium! :L Of course there are two arrows! :L

    I'm glad I'm not alone in this. It scared me :(


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    #685
    FaoiSin
    Registered Users Posts: 789 ✭✭✭FaoiSin


    Oh god. It's going backwards... 18 marks :(


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    #686
    RedTexan
    Registered Users Posts: 217 ✭✭RedTexan


    finality wrote: »
    Some guy was saying that because the top arrow was pointing backwards you had to reverse the reaction and invert Kc. I disagree but he seemed quite adamant about it (and patronising).
    That's his logic? I think he might have been reading into it a little too much. The position of the arrows is most definitely irrelevant


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    #687
    RedTexan
    Registered Users Posts: 217 ✭✭RedTexan


    finality wrote: »
    Some guy was saying that because the top arrow was pointing backwards you had to reverse the reaction and invert Kc. I disagree but he seemed quite adamant about it (and patronising).
    That's his logic? I think he might have been reading into it a little too much. The position of the arrows is most definitely irrelevant


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    #688
    kyle84
    Registered Users Posts: 21 ✭kyle84


    if it was going backwards tho you would invert kc,don't know if it is though


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    #689
    Hayezer
    Registered Users Posts: 652 ✭✭✭Hayezer


    Doesn't every equilibrium question have a forward and backwards arrow? It's a reversible reaction.


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    #690
    TMCGY
    Registered Users Posts: 44 ✭TMCGY


    RedTexan wrote: »
    That's his logic? I think he might have been reading into it a little too much. The position of the arrows is most definitely irrelevant

    Yea sure the arrows just tell you that the reaction is going forwards and backwards isnt it?? Makes no diff which way they go?


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    #691
    Yellowstars
    Registered Users Posts: 4 ✭Yellowstars


    would you get any marks if you said propanone and propan-1-ol were isomers? i know propan1ol isnt,but just cos i said propanone? haha i know im being picky. also do esters have a fruity smell? delighted with q6 :) did ye get -224?? was there O2 in the equation for its formation ?


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