EXPLAIN THE LAW OF CONSERVATION OF MASS WITH AN EXAMPLE ?
For example: When 100g of mercuric oxide is heated, 92.6 g of mercury and 7.4 g of oxygen are obtained as products.
i.e. HgO→ Hg + O2
In this case mass of reactant =100g
Mass of products = Mass of Hg + Mass of O2 = 92.6 + 7.4 = 100g
Thus, we obtain Mass of product = Mass of reactants
This verifies the law of conservation of mass.
The law of conservation of mass, or principle of mass conservation, states that for any system closed to all transfers of matter and energy (both of which have mass), the mass of the system must remain constant over time, as system mass cannot change quantity if it is not added or removed.
In a chemical reaction, the mass of the reactants before the reaction and the mass of the reactants after the reaction will be same. That is, Mass can neither be destroyed nor be created.
- Take the example of burning a piece of paper. It seems that the mass shrinks as the paper burns. However, what is really happening is that the paper is changing form to ash, carbon dioxide, and water vapor.
If you could capture all of those bits during the burning, they would have the same mass as the paper itself.
- When you react 2 molecules of hydrogen gas (H2) with 1 molecule of oxygen gas (O2), you will get 2 molecules of water (H2O):
2 H2 + 1 O2 –› 2 H2O
Notice in the equation above that you started with 4 atoms of hydrogen and 2 atoms of oxygen, and you ended with 4 atoms of hydrogen and 2 atoms of oxygen.
The law of conservation of mass states that the mass of a closed system will remain constant in a chemical reaction. In other words, mass can neither be created nor destroyed in a chemical reaction. This law was first formulated by Antoine Laurent Lavoisier in 1789.For example: When 100g of mercuric oxide is heated, 92.6 g of mercury and 7.4 g of oxygen are obtained as products.i.e. HgO→ Hg + O2In this case mass of reactant =100gMass of products = Mass of Hg + Mass of O2 = 92.6 + 7.4 = 100gThus, we obtain Mass of product = Mass of reactantsThis verifies the law of conservation of mass.