(a) How many gram molecules are present in `4.9` g of `H_(2)SO_(4)` ?
(b) Calculate the mass of `0.72` gram molecules of `CO_(2)`.

Explanation

(a) Molecular mass of `H_(2)SO_(4)= 2xx` Atomic mass of `H +` Atomic mass of `S + 4 xx` Atomic mass of `O`
`= 2xx1+32+4xx16=98u`
Gram molecular mass of `H_(2)SO_(4)=98` g
`98` g of `H_(2)SO_(4)=1` gram molecule
`4.9` g of `H_(2)SO_(4)=(1)/(98)xx4.9 = 0.05` gram molecule
(b) Molecular mass of `CO_(2)=` Atomic mass of `C+2xx` Atomic mass of `O`
`= 12+12 xx16=44 u`
Gram molecular mass of `CO_(2)=44g`
`1` gram molecule of `CO_(2)` has mass `= 44 g`
`0.72` gram molecule of `CO_(2)` has mass `= (1)/(44)xx0.72=0.016g`.