1. Chemical Equations By: Mr. Castillo & Ms. Garcia

2. Chemical Equations We learned that elements and compounds chemically react and exchange atoms. That, during the reaction the atoms are rearranged into a new substance. Today, we will learn that these reactions must be balanced.

3. Chemical Equations Chemical equation: A short way of showing a balanced chemical reaction using symbols, subscripts, and coefficients. Example: 2H 2 + O 2 2H 2 O ( 4 Hydrogen and 2 oxygen )( 4 Hydrogen and 2 oxygen ) Chemical equations have an equal number of elements and atoms on both sides of the reaction.

4. Chemical Equations Chemical equation examples:

5. Law of conservation of Mass Conservation of Mass: States that mass is neither created nor destroyed in any chemical reaction; mass remains balanced. Conservation: To save. Balanced: Even or equal.

6. Conservation of Mass Conservation of mass examples: Reactants -------> Products Mass of Reactants = Mass of Products Iron + Oxygen -----> Rust 100 g + 43g --------> 143g mass reactants = mass products mass products = 143g = mass reactants

7. Review Any questions???