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    Okay so I've just done a quantitative assessment on water of crystallisation.

    I had had to work out the metal 'X' in the formula XCl2 • 2H2O

    what I'm stuck on:

    determine the the amount in mol of anhydrous salt (XCl2)

    mass of of anhydrous salt = 1.68g

    so the equation is

    n(XCl2) = 1.68g / x + (35.5 + 35.5)

    how the bloody hell do I rearrange this to work out the Mr/ moles?

    Ps Im terrible at maths so the answer could be really simple lol
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    (Original post by Georgiam247)
    Okay so I've just done a quantitative assessment on water of crystallisation.

    I had had to work out the metal 'X' in the formula XCl2 • 2H2O

    what I'm stuck on:

    determine the the amount in mol of anhydrous salt (XCl2)

    mass of of anhydrous salt = 1.68g

    so the equation is

    n(XCl2) = 1.68g / x + (35.5 + 35.5)

    how the bloody hell do I rearrange this to work out the Mr/ moles?

    Ps Im terrible at maths so the answer could be really simple lol
    You need the mass of water lost ...
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    (Original post by charco)
    You need the mass of water lost ...
    To workout that particular thing? I thought it was n = M/m
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    (Original post by Georgiam247)
    To workout that particular thing? I thought it was n = M/m
    You thought wrong ...
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    (Original post by charco)
    You thought wrong ...
    Well can you please tell me how I forgot the water loss but can you give me a hypothetical example? Say the hydrate was 2.525g, and the anhydrous was 1.68g
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    (Original post by Georgiam247)
    Well can you please tell me how I forgot the water loss but can you give me a hypothetical example? Say the hydrate was 2.525g, and the anhydrous was 1.68g
    Oh my God. It's just the same as the moles of water lost isn't it.
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    (Original post by Georgiam247)
    Oh my God. It's just the same as the moles of water lost isn't it.
    mass of water lost ===> moles of water lost

    use the given formula to get moles of anhydrous salt from moles of water

    moles of anhydrous salt and mass ====> relative mass and hence X
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    (Original post by charco)
    mass of water lost ===> moles of water lost

    use the given formula to get moles of anhydrous salt from moles of water

    moles of anhydrous salt and mass ====> relative mass and hence X

    Woo thank you
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    PLEASE HELP!Just wondering if anyone would be able to help ASAP? I found the number of moles for h2o to be 0.04694 by doing 0.845 divided by 18 and divided that by 2 to find XCl2 equals 0.02347mol. I then divided that by 1.68 (mass of anhydrous salt) and found the Mr of it to be 71.57gmol.
    I thought that I'd do 71.51 - 71 (Mr of Cl2) to find X but that can't be correct?
 
 
 
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