Question

Mass of one atom of an element is 6.645 × 10⁻²³ g. How many moles of element are there in 0.320 kg.

Answer 1

Given: Mass of one atom = 6.645 × 10^–23 g

∴ Mass of 1 mole of atom = 6.645 × 10^–23 g × 6.022 × 10²³

= 40 g

∴ Number of moles of element in 0.320 kg = `(1  "mole")/(40  "g") xx 0.320` kg

= `(1  "mol" xx 320  "g")/(40  "g")`

= 8 mol.