1. Aim: What are the five general types of reactions? Do Now: Write and balance the Chemical Equation 1.Zinc and lead (II) nitrate react to form zinc nitrate and lead. 2. Potassium metal and chlorine gas combine to form potassium chloride Zn + Pb(NO 3 ) 2  Zn(NO 3 ) 2 + Pb 2K + Cl 2  2KCl

2. Types pf Reactions The five general types of reactions are:  Combination/Synthesis Reactions  Decomposition  Single-Replacement  Double-Replacement  Combustion

3. Combination/Synthesis Reaction  A combination or synthesis reaction is a chemical change in which two substances react to form a new single substance.  A + B  AB  N 2 + 3 Cl 2 → 2 NCl 3

4. Decomposition Reaction  A decomposition reaction is a chemical change in which a single compound breaks down into two or more simpler products.  AB  A + B  2 HgO → 2 Hg + O 2

5. Single-Replacement Reaction  A single-replacement reaction is a chemical change in which one element replaces a second element in the compound.  A + BC → AC + B  Cu + 2 AgNO 3 → Cu(NO 3 ) 2 + 2 Ag

6. Activity Series  Each metal in the activity series displaces any metals below it to form a salt in solution.  More active metals replace less active metals.

7. Double-Replacement Reaction  A double-replacement reaction is a chemical change in which there is an exchange of positive ions between compounds.  Occurs when different atoms in two different compounds trade places.  AB + CD  AD + CB  BaCl 2 + K 2 SO 4 → BaSO 4 + 2 KCl

8. Combustion Reaction  A combustion reaction is a chemical change in which an element or a compound reacts with oxygen, often producing energy in the form of heat or light.  CH 3 OH + O 2  CO 2 + 2H 2 O + heat  2Mg + O 2  2MgO + heat

9. Follow this series of questions. When you can answer "yes" to a question, then stop! 1) Does your reaction have oxygen as one of it's reactants and carbon dioxide and water as products? If yes, then it's a combustion reaction 2) Does your reaction have two (or more) chemicals combining to form one chemical? If yes, then it's a synthesis reaction 3) Does your reaction have one large molecule falling apart to make several small ones? If yes, then it's a decomposition reaction 4) Does your reaction have any molecules that contain only one element? If yes, then it's a single displacement reaction 5) If you haven't answered "yes" to any of the questions above, then you've got a double displacement reaction