Question

A necklace contains 0.250 mol of silver. How many atoms of silver are in the necklace

Answer 1

In one mole of any substance, there are 6.022·10²³ formula units (Avogadro's number). Therefore, in 0.250 mol of silver:

$N = N_A·n = 6.022·10^{23}·0.250 = 1.51·10^{23}$ atoms.

Answer: There are 1.51·10²³ atoms in the necklace.