Calculate the number of
(i) gram atoms in 669.6 g of iron (at. mass = 55.8)
(ii) gram molecules in 73.6 g of `C_(2)H_(5)OH`.

Answer

A, B

Explanation

(i) Atomic mass of iron = 55.8
55.8 g of iron = 1 gram atom
669.6 g of iron `=1/(55.8) xx 669.6=12` gram atom.
(ii) Molecular mass of `C_(2)H_(5)OH = 2 xx 12 + 5 xx 1 xx 16 + 1 xx 1=46`
46 g of `C_(2)H_(5)OH =1` gram molecule
73.6 g of `C_(2)H_(5)OH =1/46 xx 73.6= 1.6` gram molecule.