Answer:
1.915 x 10²³ atoms Pb
Step-by-step explanation:
To find the amount of atoms, you need to (1) convert grams to moles (via atomic mass of lead) and then (2) convert moles to atoms (via Avogadro's Number). It is important to arrange the conversions in a way that allows for the cancellation of units (the desired unit should be in the numerator). The final answer should have 4 sig figs to match the given value (65.89 g).
Atomic Mass (Pb): 207.20 g/mol
Avogadro's Number:
6.022 x 10²³ atoms = 1 mole
65.89 g Pb 1 mole 6.022 x 10²³ atoms
------------------ x ---------------- x ------------------------------- = 1.915 x 10²³ atoms Pb
207.20 g 1 mole