1. Word Equations ◦ use the IUPAC names of the chemicals ◦ use a + for “reacts with” ◦ an arrow  for “to produce” Ex: iron + oxygen  iron (III) oxide

2. Skeletal Equations ◦ chemicals written using symbols, but is not yet balanced ◦ Can include information about the state (s), (l), (g), (aq) Ex: Fe (s) + O 2(g)  Fe 2 O 3(s)

3. Balanced Chemical Equations ◦ represents the ratio in which the chemicals must react in order to carry out the reaction and the ratio in which the products are formed ◦ Law of Conservation of Mass Ex: 4Fe (s) + 3O 2(g)  2Fe 2 O 3(s)

 We use coefficients to balance chemical reactions  Coefficients are the numbers that show the ratio in which the species must react Ex: Ca + 2 H 2 O  Ca(OH) 2 + H 2

 Start by balancing species that are NOT O or H  Try to keep polyatomic ions together  Reduce coefficients to lowest possible ratio  Double Check!!

Lets Practice!!

Single Displacement Synthesis Decomposition Double Displacement A + B  C AB + CD  AD + CB AB + C  AC + B AB  A + B

 Balancing Practice from Worksheet  p. 118 #2