Question

How many atom are present in a piece of iron that has a mass of 65.
0g​

Answer 1

Iron has an atomic mass of 55.845 g/mol, so the amount of iron in 65.0 g is 65.0/55.845 = mol.

Avogadro's law states that in every mole of a substance, there are
`6.022 * 10^(23)` particles per mole, so in this case, that means there are
`(1.16393589)(6.022 * 10^(23))=\boxed{7.01 * 10^(23)} \text{ atoms (to 3 sf)}}`