6.1- The Nature of Chemical Reactions I CAN: -ANALYZE THE FLOW OF THERMAL ENERGY AND DETERMINE IF IT IS TRANSFERRED FROM THE SYSTEM TO THE SURROUNDINGS OR TRANSFERRED FROM THE SURROUNDINGS TO THE SYSTEM (ENDOTHERMIC VS EXOTHERMIC). -RECOGNIZE THAT TEMPERATURE CHANGE IN THE SURROUNDING MAY NOT BE DETECTABLE DUE TO THE LARGE SIZE OF THE SYSTEM

Chemical Reactions Change Substances Grow, ripen, decay, and burn… Even your own health… What causes bread to rise? Chemical reactions rearrange atoms Reactant: substance or molecule that participates in a chemical reaction Product: substance that forms in a chemical reaction.

Energy and Reactions Isooctane and oxygen= burning gasoline. Need energy to get started (Where does it come from) Added energy breaks covalent bonds. Chemical energy: the energy released when chemical compounds react to produce new compounds.

Exothermic vs. Endothermic Ex (exit) othermic reaction: heat is released into surroundings. Temp rises Combustion of fuels En (enter) dothermic reaction: chemical reaction that requires heat. More energy needed to break bonds than is given off. May notice a drop in temp. Melting or dissolving

6.2 Reaction Types I CAN: -DEMONSTRATE CONSERVATION OF MATTER BY WRITING BALANCED CHEMICAL EQUATIONS. -IDENTIFY REACTANTS AND PRODUCTS AND SIMPLE EQUATIONS CAN BE WRITTEN AND BALANCED GIVEN EITHER THE FORMULAS OF THE REACTANTS AND PRODUCTS OR A WORD DESCRIPTION OF THE REACTION.

Classifying Reactions Synthesis Reaction: two or more substances combine to form a new compound. (Synthesis= make something… think photo) A + B  AB 2Na + Cl 2  2NaCl Decomposition Reactions: single compound breaks down to form two or more simpler substances. ( think decompose=break down) AB  A + B 2H 2 0  2H Electrolysis= process in which an electric current is used to produce a chemical reaction, such as the decomposition of water. Combustion reaction: oxidation reaction of an organic compound, in which heat is released.

Single-displacement reactions: one element takes the place of another element in a compound. AX + B  BX +A 3CuCl 2 + 2Al  2AlCl 3 + 3Cu The more reactive element will take the place of a less reactive one. Double-displacement reaction: a gas, a solid, or molecular compound forms from the exchange of atoms between two compounds. AX + BY  AY + BX Pb(NO 3 ) 2 + K 2 CrO 4  PbCrO 4 + 2KNO 3