21-3 Classifying Chemical Reactions You will be learning: 1.How to identify the four general types of chemical reactions. 2.How to predict which metals will replace other metals in compounds.

Types of Reactions Combustion –Any time something is burning –A combustion reaction occurs when a substance reacts with oxygen to produce energy in the form of heat and light.

Synthesis Reaction When 2 or more substances combine to make 1 new substance H 2 + O H 2 O

Decomposition Reaction When one substance breaks down (decomposes) into two or more substances. H 2 O H 2 + O

Single Displacement When one element replaces another element in a compound. Zn + CuSO 4 Zn SO 4 + Cu

Double Displacement When a positive ion of one compound replaces the positive ion of the other to form 2 new compounds. CuCl 2 + H 2 S CuS + 2HCl

Precipitate is an insoluble compound that comes out of solution during a double displacement reaction.

Activity Series Predict which metal will replace another using Figure 13 p Lists metals according to how reactive they are. A metal will replace any less active metals.

Oxidation-Reduction Reactions Oxidation describes the loss of electrons during chemical changes. Reduction describes the gain of electrons during chemical changes. Oxidation and reduction work together (take an electron from one atom and it will join a different atom). This is called redox.

What type of reaction? Cl + NaBr NaCl + Br 2 SINGLE DISPLACEMENT

What type of reaction? KClO 3 KCl + O 2 DECOMPOSITION