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    if you have 1.5cm cubed of 0.2 molarity iron chloride, why is it if you mix it with 0.5 water you get 0.15 molarity. and if u 1.25 water with 0.75 fecl3 you get 0.075 and so on.
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    0.0003moles of FeCl in the first
    if you add 0.5cm^3 water you get 2cm^3 of 0.15M

    yes that's correct. What's the problem? You use the equation:

    moles = concentration*volume
    where the volume is in dm^3 (to convert from cm^3, divide by 1000)
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    im assuming you mean 0.5 cm³ water....

    originally: n = cv = 0.2 * 0.0015 = 0.0003 moles FeCl3

    0.5 cm³ water is added, but the moles of iron chloride stays the same, so
    c = n/v = 0.0003/(0.0015 + 0.0005) = 0.15 M
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    if the solid was pure: you would take the required mass of solid (i believe the rmm of FeCl3 is 162.5). so 162.5g of the pure solid dissolved in 5l of pure water would make a 0.2M solution. you can then use that to make the other solutions
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    how does "elpaw" make me polish? it could be "the paw" in spanish.

    as for my knowledge, i did Alevel Chemistry.
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    ok i thought you meant - my name "elpaw"
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    yeah, 4 As
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    Someone's been deleting posts...
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    (Original post by mik1a)
    Someone's been deleting posts...
    either that or elpaws goin crazy..
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    (Original post by ShOcKzZ)
    either that or elpaws goin crazy..
    there were posts there a minute ago
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    (Original post by ShOcKzZ)
    either that or elpaws goin crazy..
    Good point. Eplaw's finally lost it. :eek:
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    (Original post by mik1a)
    Good point. Eplaw's finally lost it. :eek:
    Lol...someone's framing Elpaw...
 
 
 

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