Law of Conservation of Mass
Law of Conservation of Mass: In science, in accordance with the law of conservation of mass or principle of mass conservation for any closed system all the matter or energy transfers must remain constant over time. As the mass of the system does not change, so the quantity can neither be added nor removed. Therefore, the quantity remains the same. Hence it is conserved. The concept of the Law of conservation was discovered by Antoine Lavoisier in the year 1789.
Explanation of Law of Conservation of Mass
According to the law of conservation of mass," Mass can neither be created nor destroyed, it may be transformed from one form to the other form". For instance, in chemical reactions, the mass of the chemical components before the reaction is equal to the mass of the components after the reaction.
Law of Conservation Formula
According to this law, in a chemical reaction, the mass of products in chemical reactions equals the mass of reactants. We can express the law of conservation of mass in differential form by an equation of the mechanics of fluids and continuum mechanics with the following equation-
∂ρ/∂t +⛛(ρv) = 0
ρ indicates the density
t indicates the time
v indicates the velocity
⛛ indicates the divergence
Law of Conservation of Mass Examples
When Matter Undergoes a Physical Change
Take a cube of ice (ice is solid water) and place it in a flask. Properly weigh the flask and then heat it gently to melt the ice into water.
Ice(solid) → Heat → Water(Liquid)
Again, after heating weighs the flask you will notice that the weight remains constant. It has only undergone a physical change.
When Matter Undergoes a Chemical Change
One tube contains a solution of sodium chloride and another contains a silver nitrate solution; The tube which contains these two solutions is called Landolt’s tube. Both tubes were corked and then weighed. The chemical reaction occurs which forms a curdy white precipitate of silver chloride. The chemical reaction is-
NaCl (s) + AgNO3 (aqueous) → AgCl (s) + NaNO3 (aqueous)
After this reaction, it was held that the weight remains the same.