Question

(ii) Calculate the number of molecules of sulphur (S8)
present in 128gm of sulphur.(atomic mass of Sulphur is
32gm).


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Answer 1

Answer:

The molecules formula of sulphur is given to be S8 ( it Contains 8 atoms of sulphur ). So , the molecular mass of sulphur molecule is 32 × 8 = 256 u. This means that 1 mole of sulphur molecules is equal to 256 grams.

Now, 256 g of sulphur = 1 mole of sulphur molecules

So, 16 g of sulphur = 1/ 256 × 16 mole of sulphur molecules

= 0.0625 mole of sulphur molecules

Also, 1 mole of sulphur molecules = 6.023 × 10²³ molecules

So, 0.0625 mole of sulphur molecules = 6.025 × 10²³ × 0.0625 molecules

= 3.76 × 10²² molecules