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Avogrado's constant question. Watch

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    The question is from June 2011 CCEA it asks :

    "Using Avogadro's Constant calculate the number of astatine atoms that exist in 30g astatine. Assume that all atoms are of astatine-210."

    So I did the calculation for n and got 8.6 times 10^22 and then multiplied this number by 2 because astatine is diatomic. However the mark scheme says my original answer ; 8.6 x 10 ^ 22, is correct. This is especially confusing as the next question requires me to state that astatine is diatomic. Any ideas as to where I have went wrong here?
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    (Original post by eoinoneill2506)
    The question is from June 2011 CCEA it asks :

    "Using Avogadro's Constant calculate the number of astatine atoms that exist in 30g astatine. Assume that all atoms are of astatine-210."

    So I did the calculation for n and got 8.6 times 10^22 and then multiplied this number by 2 because astatine is diatomic. However the mark scheme says my original answer ; 8.6 x 10 ^ 22, is correct. This is especially confusing as the next question requires me to state that astatine is diatomic. Any ideas as to where I have went wrong here?
    If you are going to calculate astatine molecules then you must divide the mass by the relative mass of a molecule = 420 and then multiply by Avogadro's number

    Only then should you multiply by 2.
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    (Original post by charco)
    If you are going to calculate astatine molecules then you must divide the mass by the relative mass of a molecule = 420 and then multiply by Avogadro's number

    Only then should you multiply by 2.
    Ah ok, apologies that was a bit of a brain fart. Thanks for the help, charco.
 
 
 
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