Question

5.2g of CaCO3 when heated produced 1.99g of carbaon dioxide and the residue (CaO) left behind weighs 3.2g. show that these results illustrate the law of conservation of mass

Answer 1

Chemical reaction:
CaCO3  ----> CaO  +    CO2
5.2g                  3.2g      1.99g
Total mass of reactants= 5.2g
total mass of products= 3.2 +1.99⇒5.19≈5.2g
∴total mass of reactants= total mass of products.
Hence law of conservation of mass is satisfied which states that mass in a chemical reaction is neither destroyed nor created.