Chemical Equations

By: Mr. Castillo & Ms. Garcia

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.

Chemical Equations• Chemical equation: A short way of showing a

balanced chemical reaction using symbols, subscripts, and coefficients.

• Example: 2H2 + O2 2H2O (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.

Chemical Equations

• Chemical equation examples:

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.

Conservation of Mass

• Conservation of mass examples: Reactants -------> Products

• Mass of Reactants = Mass of ProductsIron + Oxygen -----> Rust

100 g + 43g --------> 143g • mass reactants = mass products • mass products = 143g = mass reactants

Review

• Any questions???