Question

The mass of cao that shall be obtained by heating 20kg of 90% pure limestone caco3 is

Answer 1

Rxn involved -

   CaCO3 →  CaO +  CO2

due to 90% purity,  mass of CaCO3 available  is   20× 0.9  =  18gm

so no. of moles of CaCO3 = 18/100 = 0.18

and 1 mole of  CaCO3   yields  1 mole of CaO

therefore,  mass of CaO produced =  0.18 ×  56 = 10.08 gm

hope this helps