1. UNIT 7 - CHEMICAL REACTIONS Section 2 - Types of Reactions 1. Classified by type of reactants or number of reactants and products. 2. Describes the different ways in which reactants interact to form products. Definitions: Reactants - the substances that will undergo change in a chemical reaction. Products - the new substances that are formed as a result of the chemical reaction. Reactants ----> Products Carbon + Oxygen ----> Carbon Dioxide

2. Types of Reactions 1. Synthesis - a reaction in which two or more substances react to form a single new substance. 2. Decomposition - a reaction in which a compound breaks down into two or more simpler substances. 3. Single Replacement - a reaction in which one element takes the place of another element in a compound. 4. Double Replacement - a reaction in which two different compounds exchange positive ions and form new compounds. 5. Combustion - a reaction in which a substance reacts with oxygen, often producing heat and light. 6. Oxidation-Reduction - a reaction in which electrons are transferred from one reactant to another.

3. Synthesis - a reaction in which two or more substances react to form a single new substance. (The case of the new couple.) Reactant + Reactant ---> Product ME + YOU = WE 2Na + Cl 2 = 2 NaCl A + B = AB

4. Decomposition - a reaction in which a compound breaks down into two or more simpler substances. (The case of the break up!) Reactant -----> Product + Product Let's Split! Sob! I was so happy. They -----> He + She AB ------> A + B CaCO 3 -------> CaO + CO 2

5. Single Replacement - a reaction in which one element takes the place of another element in a compound. (The case of the flirt.) I like you Hmm, who's that good look'n chick? Hey Baby Traitor! Gal 1 Couple 1 Gal 2 Couple 2 A + BC -------> B + AC Cu + 2AgNO 3 --------> 2Ag + Cu(NO 3 ) 2 Reactant 1 + Reactant 2 -----> Product 1 + Product 2

6. Double Replacement - a reaction in which two different compounds exchange positive ions and form new compounds. (The case of the bad double date.) He's Cool! She's Hot! Well, I never! Reactant 1 + Reactant 2 -----> Product 1 + Product 2 Couple 1 Couple 2 Couple 3 Couple 4 AB + CD --------> CB + AD Pb(NO 3 ) 2 + 2KI --------> PbI 2 + 2KNO 3

7. Combustion - a reaction in which a substance reacts with oxygen, often producing heat and light. Reactant + Oxygen -----> Product + Water + Heat/Light CH 4 + 2O 2 --------> CO 2 + 2H 2 O + Heat/Light Oxidation-Reduction - a reaction in which electrons are transferred from one reactant to another. (Ionic bonding) 2Ca + O 2 ------> 2CaO neutral neutral -----> 2Ca + O - (cations/anions bonded to each other)

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