Respostas

2013-07-26T16:44:32-03:00
Massa Molar Carbono C = 12g/mol.

1 mol = 6,02 * 10^23 átomos de carbono.

1mg = 10^-3g
12g --------------------- 1 mol
10^-3 -------------------x mols

12x = 10^-3

x = 10^-3 / 12 = 8,3 * 10^-5 mols de Carbono.


1 mol ------------------- 6,02 * 10^23 atomos

8,3*10^-5 --------------------x atomos

x= 8,3*10^-5 * 6,02*10^23

x=  49,96 * 10^18

arredondando

x = 50 * 10^18

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x = 5*10^19 atomos de Carbono em 1mg de grafite aproximadamente
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2013-07-26T16:45:55-03:00
Resolução1 mol de C ---------- 12 g de C ---------- 6 ∙ 1023 átomos de C0,0012 g de C ---------- x 

x = 6 ∙ 1019 átomos de C