Chapter 6 – 2 Warm - Up 1. What is a chemical reaction? 2. What is one sign that a chemical reaction has taken place? 3. What is the difference between an exothermic and an endothermic reaction? 4. What idea did Antoine Lavoisier come up with?

Chapter 6 – 2 Chemical Reactions Types of Reactions

Types of Reactions Chemists have defined 6 types of chemical reactions: Combustion Synthesis Decomposition Single displacement Double displacement Oxidation-Reduction Reaction

Synthesis Reactions Synthesis reaction - two or more substances combine to form another substance. A + B  AB 2 Na + Cl2  2 NaCl

Synthesis Reactions Metal sodium reacts with chlorine gas for form sodium chloride Table Salt 2Na + Cl2  2NaCl

Synthesis Reactions Glucose and oxygen gas form carbon dioxide and water Photosynthesis 6CO2 + 6H2O  C6H12O6 + 6O2

Decomposition Reactions Decomposition reaction - one substance breaks down, or decomposes, into two or more substances Reverse of a synthesis reaction AB  A + B 2H20  2H2 + 02 Most require the use of heat, light, or electricity

Decomposition Reactions Digestion Electrolysis – process where an electric current is used to produce a chemical reaction Metals resistant to corrosion Production of oxygen in subs Metal decoration Hair removal 2H2O  2H2 + O2

Combustion Reactions Combustion reaction - a substance reacts with oxygen to produce energy in the form of heat and light. Something burning Heat is released

Single Displacement Single-displacement reaction - One element replaces another element in a compound A + BC  AC + B 2Al + 3CuCl2  2AlCl3 + 3Cu

Single Displacement Aluminum undergoes a single-displacement reaction with copper (II) chloride to form copper and aluminum chloride 3CuCl2 + 2Al  2AlCl3 + 3Cu

Single Displacement Potassium reacts with water in a single replacement reaction to form potassium hydroxide and hydrogen K + H2O  KOH + H2

Double Displacement Double displacement - a precipitate, water, or a gas forms when two compounds in solution are combined AB + CD  AD + CB Pb(N03)2 + K2CrO4  PbCrO4 + 2KNO3

Oxidation-Reduction Reaction Oxidation-Reduction Reaction – chemical change where one part is oxidized (loses electron) and another part is reduced (gains electron) Redox Reaction

Oxidation-Reduction Reaction Respiration Combustion

Radials Radical – an organic group that has one or more electrons available for bonding Used to make polystyrene foam or insulation