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1. 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?
2. (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.
3. (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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