Answer:
- Law of conservation of mass
Step-by-step explanation:
1.Law of conservation of mass : Matter can neither be created nor destroyed in a chemical reaction .
or
Total mass of Reactants should be equal to total mass of product.
Use : This law is used to balance the chemical reaction
it helps in calculating amount of product formed
2.Naming "Oxygen":
He deduced that combustion and respiration are occuring from some molecule. He named that element as "Oxygen"