Hello!
To find the number of moles present in 16.2 grams of lead, we need to know how much one mole of lead weighs.
1 mole is equal to the atomic mass of an element, so, 1 mole of lead is equal to about 207.2 grams.
To find that, divide the given amount of lead by 1 mole of lead (207.2 grams).
16.2 grams / 207.2 grams ≈ 0.07818
Therefore, the amount of moles present in 16.2 grams of lead is about 0.078 moles. (round to amount of sigfigs: 0.0782 moles)