Question

In 96.0 gm of Sulphur, calculate 

(i) the number of gram atoms of the element, 

(ii) the number of gram molecules, if a molecule of Sulphur has the formula, S₈, 

(iii) the number of atoms of Sulphur, and 

(iv) the number of molecules. (At. wt. S = 32, Avogadro's number, N 6.02 x 10²³ molecules per mole),

Answer 1

(i) Atomic weight of Sulphur = 32

1 gm atom of Sulphur = 32 gm

\(\therefore\) No. of gram atoms in 96 gm of Sulphur = \(\frac{96}{32}\) = 3

(ii) Molecular weight of S₈ = 32 × = 256

\(\therefore\) No. of gram atoms in 96 gm of sulphur

= \(\frac{96}{256}\) = 0.375

(iii) 32 gm (1 gm atom) of Sulphur contain 6.02 × 10²³ atoms.

96 gm of Sulphur contains \(\frac{6.02}{32}\times96\times10^{23}\)

= 1.806 × 10²⁴ atoms.

(iv) 256 gm (1gm molecule) of Sulphur contain 6.02 × 10²³ molecules

96 gm of Sulphur contains \(\frac{6.02}{256}\times96\times10^{23}\)

= 2.257 x 10²³ molecules