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    I'm confused :confused: did you guys dissolve the Na2CO2? if so, what solvent did you use? AND how did you find the number of moles of water? tnx in advance!
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    Guys, I've found a VERY useful bit of information (well.. useful to me..) "Sodium carbonate has three known form of hydrates: sodium carbonate decahydrate, sodium carbonate heptahydrate and sodium carbonate monohydrate." That's from Wikipedia for your Bibliography. Its significance, should, I think, be obvious. Suzukieskudo, your '8' might be wrong.. dunno. I've only just started tonight.. just started research.. no actual work yet.

    Um Shylock.. maybe I'm just blind (lol I am actually going for new lenses tomorrow) but where is that other thread!!!? Cheers!
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    Good grief! I've gone back 6weeks to find traces of any other threads. Apologies Shylock, I did find two others which I presume you must have been referring to.. but they were shorter than this one and didn't say anything else. The A2 Bio planning thread has just made it to 13pages, so I was a little dissapointed.. but that's prob because people like me turned it into a chat room in order to procrastinate the torture!!!

    Does anybody think it would be possible to do titrations of each of the three diff types of hydrates, and then titrate compound x and match it up to the others to see which hydrate it is? There are only 3. I can't think of any other way that a titration would allow you to find out the formula, seeing that its all in aqueous solutions so you can't trace water lost!
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    the work is rediculous anyway! the whole titration scene is rubbish, i dont think anyone understands how to find X from conducting a titration... as well as having to give this in on wednesday... i also have the PPP for PE to do, and all my friends have physics planning... we are all all swamped with work...

    Background info -
    (what specifically needs 2 be here?)

    Method 1 (heating)
    (calculations?)

    Method 2 (titraiton)
    (calculations?)

    im clueless here
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    (Original post by Craghyrax)


    Does anybody think it would be possible to do titrations of each of the three diff types of hydrates, and then titrate compound x and match it up to the others to see which hydrate it is? There are only 3. I can't think of any other way that a titration would allow you to find out the formula, seeing that its all in aqueous solutions so you can't trace water lost!
    How exactly do you titrate a dehydrated substance? Think! Use a suitable solvent.
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    Suzukieskudo, your '8' might be wrong.. dunno.
    nooo!!

    are you sure, it must be 8!
    please some1 back me up.

    pratty, what did you write in your intro?
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    (Original post by Baal_k)
    How exactly do you titrate a dehydrated substance? Think! Use a suitable solvent.
    The molecule is hydrated! otherwise number moles h20 = 0!
    This nulifies the question!

    Plus, it is water soluble.

    (Original post by suzukiescudo)
    nooo!!

    are you sure, it must be 8!
    please some1 back me up.

    pratty, what did you write in your intro?
    Wiki says the only known hydrates of na2co3 are 10, 7 and 1. hence one of those should be your answer.
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    (Original post by Baal_k)
    How exactly do you titrate a dehydrated substance? Think! Use a suitable solvent.
    can i use an organic solvent (such as methol?)
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    tozhan: Wiki says the only known hydrates of na2co3 are 10, 7 and 1. hence one of those should be your answer.
    whos wiki?
    also if its not eight then how?
    i dont understand.... where have i gone wrong?
    im gona ask my teacher. oh yea shes on maternity leave....
    damn!
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    (Original post by suzukiescudo)
    whos wiki?
    also if its not eight then how?
    i dont understand.... where have i gone wrong?
    im gona ask my teacher. oh yea shes on maternity leave....
    damn!
    Wiki is short for wikipedia. Type it into Google, and then look up Sodium Carbonate in its search field.
    Read that first.
    Then.. if you can explain how you came up with 8, then we'll see if we can figure out how you found it. You might not be too far off, seeing as one of the known hydrated forms of Sodium Carbonate is a heptahydrate :cool:
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    (Original post by Baal_k)
    How exactly do you titrate a dehydrated substance? Think! Use a suitable solvent.
    Its not a dehydrated substance. The paper indicates using hydrated crystals. Even if it were dehydrated, the aim is to determine the formula of the hydrated form.
    Sodium Carbonate is water soluble, so there's no need for any special solvent.
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    yepp... all my mates got 10 for no of moles of H2O! anybody with any relevant calculations?!
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    Balanced equation:
    Na2CO3 + 2HCl --> 2NaCl + H2O + CO2
    1 mole 2 moles 2 moles 1 mole 1 mole

    is this correct?
    can some1 please correct it...
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    theres nothing wrong with it!!

    its balanced!

    but u gotta use superscipt or subscript to get the numbers smaller.... and in the right place, otherwise u will lose marks for qwc (2 Marks)
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    theres nothing wrong with it!!
    its balanced!
    yes, i think i have finally got round to balance the equations.
    cheers for that karsh!!
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    (Original post by karsh)
    yepp... all my mates got 10 for no of moles of H2O! anybody with any relevant calculations?!
    Well there we go then.. that fits. It must be the SodiumCarbonateDecahydrate form then.

    (Original post by suzukieskudo)
    Balanced equation:
    Na2CO3 + 2HCl --> 2NaCl + H2O + CO2
    1 mole 2 moles 2 moles 1 mole 1 mole

    is this correct?
    can some1 please correct it...
    Erm.. that doesn't explain how you got 8. So if you want feedback on whether 8 is right or not you need to explain how you did that... what calculations you used and logic you relied on.

    I'll do my best to help out with calculations when I start writing it up tonight. Just in looking at it with my mates this morning we decided we were going to work it out by subtracting the Mr of sodium carbonate (* no.moles determined by titration) from the original mass of the hydrate.. then divide the answer to that by Mr water. I'll see what I come up with later.
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    (Original post by Coolraj)
    can i use an organic solvent (such as methol?)
    I think you mean methanol. and no you shouldnt use it, its poisonous, flamable and volitile.


    Fancy organic solvents are not AS level chemistry, water is the best solvent as craghyrax mentions dispite the fact that this will further hydrate the crystals. This doesnt matter because you measure the weight of your crystals before you dissolve them.

    EDIT: ok except cyclohexane....i think that one is mentioned...once...
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    (Original post by karsh)
    the work is rediculous anyway! the whole titration scene is rubbish, i dont think anyone understands how to find X from conducting a titration... as well as having to give this in on wednesday... i also have the PPP for PE to do, and all my friends have physics planning... we are all all swamped with work...

    <snip>

    im clueless here
    I think the idea is that by doing a titration you can determine an unknown concentration, in this case, the concentration of sodium carbonate which has been dissolved in water. Additionally, you know what mass of hydrated sodium carbonate you added to what volume of water. So for a certain volume of water, you know the mass of hydrated sodium carbonate, and you know the amount (no of mol) of sodium carbonate. If you know the amount of sodium carbonate in a certain volume of solution, you can work out the mass of this, and compare this with the mass of hydrated sodium carbonate - the difference is the mass of the water that formed the crystal. Work out what amount this is.

    Hope this helps.
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    OK, now I have an idea of what i'm supposed to do tnx to electric.avenue's reply, but what is it that we have to include where it says;
    the quantities of chemicals you would use in the titration experiment and calculations to show how you decided these quantities
    Am i supposed to write some sort of calculations to show how much Na2CO3 hydrate i would use? or is this where you show how you would find the value of X from the experiment? tnx in advance!
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    both really isnt it!
 
 
 
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