Answer to Question #118688 in Chemistry for madison

Question

if i have 4.56 x 10^21 atoms of silver, what is the mass of the silver?

Answer 1

The mass of the silver can be calculated from its molar mass $M$ (107.87 g/mol) and its number of the moles $n$:

$m = M·n$ .

According to the definition of the Avogadro's number $N_A = 6.022·10^{23}$ , one mole of substance contains $N_A$ of its formula units. Therefore, the number of the moles of silver is its number of atoms divided by Avogadro's number:

$n =\frac{N}{N_A} = \frac{4.56·10^{21}}{6.022·10^{23}} = 7.57·10^{-3}$ mol.

Finally, the mass of the silver is:

$m = 107.87\text{ g/mol}·7.57·10^{-3}\text{ mol} =0.817$ g.

Answer: if you have 4.56 x 10^21 atoms of silver, the mass of the silver is 0.817 g.