Question

20 g mixture of `Na_(2)CO_(3)` and `CaCO_(3)` is gently heated. On heating this sample produces 2.24 litre of `CO_(2)` at STP. Calculate the % weight of `Na_(2)CO_(3)` in that sample.

Answer 1

We know that `Na_(2)CO_(3)` does not decompose on heating. So `CO_(2)` will be produced by only `CaCO_(3)`
`CaCO_(3)(s)rarr CaO(s)+CO_(2)(g)`
By use of stoichiometric coefficient
Mole of `CaCO_(3)=(1)/(10)`
Weight of `CaCO_(3)=(1)/(10)xx100`
= 10 g
% wt. of `Na_(2)CO_(3) =(10)/(20)xx100`
= 50 %