A substance X contains 10 gram of calcium carbonate calculate the number of oxide of calcium carbonate present in X

First you have to calculate the number of moles of caco3 ! Use n=m/M ! YOH will get 0.1 moles ! By using stiochiometry you will get

O3/Caco3 = 48/100 (molar masses ) = x/0.1. ( using moles ) then you will get x = 0.048 moles

Answer; carbon monoxide (co);