Answer 1

1.6 g of Sulphur (S)

Molar mass of sulphur = 32 g mol^–1

Number of moles = `"Mass of a substance"/"Molar mass of a substance"=(1.6"g")/(32"g mol"^-1)` = 0.05 mol

Number of atoms of S = Number of moles × Avogadro's constant
= 0.05 mol × 6.022 × 10²³ atoms/mol
= 0.3011 × 10²³ atoms
= 3.011 × 10²² atoms of S

Number of sulphur atoms in 1.6 g = 3.011 × 10²² atoms of S