Question
Define the law of conservation of mass. How will you verify this law?
Solution
Law of conservation of mass (A. Lavoisier 1774) states that matter is neither created nor destroyed during any physical or chemical change and as such the total mass of the reactants before the reaction is equal to the total mass of the products after the reaction. This law is also called the law of indestructibility of matter.
Verification. This law can be verified with the help of Landolt’s experiment. Landolt took the solutions of sodium chloride and silver nitrate separately in two limbs of Landolt’s tube. The tube was weighed and sealed. After weighing, the two solutions were mixed thoroughly by shaking the tube. As a result, silver nitrate reacted with sodium chloride to from a white precipitate of silver chloride.
After the reaction, the tube was again weighed and weight was found to be the same as it was before the chemical reaction. This confirms the truthfulness of the law.
Verification. This law can be verified with the help of Landolt’s experiment. Landolt took the solutions of sodium chloride and silver nitrate separately in two limbs of Landolt’s tube. The tube was weighed and sealed. After weighing, the two solutions were mixed thoroughly by shaking the tube. As a result, silver nitrate reacted with sodium chloride to from a white precipitate of silver chloride.
After the reaction, the tube was again weighed and weight was found to be the same as it was before the chemical reaction. This confirms the truthfulness of the law.
