3 g of a hydrocarbon on combustion in excess of oxygen produces 8.8 g of CO2 and 5.4 g of H2O. The data illustrates the law of:

Mass of “C” in 8.8 as of CO2=1244×8.8=2.4gm ;  mass of “H” in 5.4 g of A2O=218×5.4=0.6g∴ total mass of (C+H)=2.4+0.6=3.0 gThus law of mass conservation is illustrated.