Law of Conservation of Mass

The law of conservation of matter says that mass cannot be created or destroyed.

In a reaction, matter cannot be created or destroyed. That means that the mass of all reactants in a reaction will be equal to the mass of all the products.
The mass can change form in the reaction, but the matter is neither created, or destroyed.

All chemical reactions can demonstrate the law of conservation of matter.

2H₂ + O₂ → 2H₂O

​Write the below equation in your notebook.

2H₂ + O₂ → 2H₂O

​Reactants

​Products

​yields

​Label your equation.

​before
on the left
goes into reaction

after
on the right
produced by reaction

​Create a T-Chart to compare and contrast reactants and products.

2H₂O → 2H₂ + O₂

​Copy this equation into your notebook.

2H₂O → 2H₂ + O₂

​coefficient

subscript

​coefficient

subscripts

​Label your equation.

2H₂O → 2H₂ + O₂

To balance a chemical equation, you can change (or add) coefficients in an equation.

​Review:

Next you will review counting atoms and bonding. You may use your notes if you want.