Write down the names of compounds represented by the following formulae.

$(i) $ $Al_{2}\left(S O_{4}\right)_{3}$

$(ii)$ $CaCl _{2}$

$(iii)$ $K_{2} S O_{4}$

$(iv)$ $KNO _{3}$

$(v)$ $CaCO _{3}$.

What is meant by the term chemical formula ?

Which postulate of Dalton’s atomic theory is the result of the law of conservation of mass ?

How many atoms are present in a 

$(i)$ $H_2S$ molecule and

$(ii)$ $PO_4^{3-}$ ion ?

Which postulate of Dalton’s atomic theory can explain the law of definite proportions ?