4.90 g of KClO3 when heated produced 1.92 g of oxygen and the residue (KCl) left behind weight 2.96 g. Show that these results illustrate the law of conservation of mass.


Correct option is

4.88 g


Mass of KClO3 taken = 4.90 g

Total mass of the products (KCl + O2)

             = 2.96 + 1.92 = 4.88 g

Difference between the mass of the reactant and the total mass of the products


Thus small difference may be due to experimental error.

Thus, law of conservation of mass hold good within experimental errors.




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