Physical Science December 7, 2011 Ms Cilli Pages
Describe the energy changes that take place during chemical reactions. Classify chemical reactions as exothermic or endothermic. Explain how energy is conserved during chemical reactions.
C 3 H 8 + 5O 2 3CO 2 + 4H 2 O
Chemical Energy: Chemical reactions involve the ________ of bonds in the reactants and the ________ of bonds in the products.
Breaking bondsForming Bonds
Is heat lost or gained? 1. A plastic bottle of water is placed in a freezer. After several hours, the water has frozen solid. 2. A chef places a stick of solid butter in a saucepan, and heats the saucepan over low heat on a stove. After several minutes, the stick of butter has melted.
Exothermic: Endothermic:
1. A plastic bottle of water is placed in a freezer. After several hours, the water has frozen solid. 2. A chef places a stick of solid butter in a saucepan, and heats the saucepan over low heat on a stove. After several minutes, the stick of butter has melted. 1. A plastic bottle of water is placed in a freezer. After several hours, the water has frozen solid. 2. A chef places a stick of solid butter in a saucepan, and heats the saucepan over low heat on a stove. After several minutes, the stick of butter has melted.
Heat is on the _____ side
All together now
Is it endothermic or exothermic? (Look and ask yourself what side the heat is on) C 3 H 8 + 5O 2 3CO 2 + 4H 2 O kJ 2HgO kJ 2Hg + O 2 Is it endothermic or exothermic? (Look and ask yourself what side the heat is on) C 3 H 8 + 5O 2 3CO 2 + 4H 2 O kJ 2HgO kJ 2Hg + O 2
Which one is not one of the 5 types of chemical reactions? a.synthesis b.decomposition c.single-replacement d.double-replacement e.All of these are chemical reactions Which one is not one of the 5 types of chemical reactions? a.synthesis b.decomposition c.single-replacement d.double-replacement e.All of these are chemical reactions
Independent Practice: – Read section 7.3 – Work on the study guide Homework: – Complete the section 7.3 HW – Due Thursday, December 8 by 8PM