Conservation of mass
When two clear solutions of lead nitrate and potassium iodide are mixed a solid, yellow substance called lead iodide is formed. The picture on the right shows the lead iodide sinking to the bottom of the beaker in which the solutions were mixed. It is obviously very heavy.


What will happen when these two solutions are mixed together? Will the total mass increase since a new substance is created?



Antoine Lavoisier n 1789 discovered that mass is neither created nor destroyed in chemical reactions. The mass of any one element at the beginning of a reaction will equal the mass of that element at the end of the reaction. Simply put the total mass of reactants before a reaction is equal to the toal mass of prodcuts after the reaction. This is known as the Law of Conservation of Mass.

Using the "Law of Conservation of Mass" explain the result shown in the video on the right when silver chromate is formed from the mixing of two solutions
Continue with an activity