Calculate the number of molecules of sulphur (S8) present in 16g of solid sulphur.

We have to find the number of molecules present in 16g of solid sulphur.
The molecular mass of the sulphur molecule is 32 × 8 = 256 u.
1 mole of sulphur molecules is equal to 256 grams.
This means 256 g of solid sulphur contains = 6.022 x 10²³ molecules.
Then, 16 g of solid sulphur contains = 6.022 x 10²³/ 256 × 16 molecules = 3.76375 x 10²² molecules
Therefore, 16 g of S8 contains 3.76 x 10²² molecules.