Question

If sulphur exists as S₈ molecules, calculate the number of moles in 100 g of sulphur. (S = 32 u)

Answer 1

Mass of sulphur = 100g (sulphur exists as S8 molecules)

molecular mass of sulphur = (8 × 32) = 256g

Number of moles in 256g of sulphur  = 1 mole

Therefore, number of moles in 100g of sulphur = 100/256 = 0.39 moles

Hence, 100g of sulphur contains 0.39 moles of sulphur.