Thursday, October 23rd, 2014

 Homework ◦ Define the following types of reactions  Synthesis  Decomposition  Single Replacement  Double Replacement ◦ Complete questions 4 and 6 from page 160 in textbook (reading from page )  Do Now  Balance the following chemical equations __Na + __HCl  __H 2 + __ NaCl __C 2 H 6 + __ O 2  __CO 2 + __H 2 O Due Tuesday: VSVS on Monday

 SWBAT identify endothermic and exothermic reactions by looking at a graph. Essential Question: How can you tell the difference between endothermic and exothermic reactions?

 Some chemical reactions produce heat ◦ what are some examples?  Some chemical reactions absorb heat ◦ What are some examples?

 Endothermic ◦ A reaction that absorbs heat  “more energy is needed to break the bonds than is given off to form new bonds.”  Exothermic ◦ A reaction that releases heat  “after an exothermic reaction the temperature of the surroundings rises because energy is releases.”  Activation energy ◦ the amount of energy (heat) needed to start a chemical reaction.  ΔH or ΔT ◦ Change in heat or temperature

 Write down a way that you can remember the difference between the two.  EXothermic = EXplosion = produces heat

 Title: Endothermic and Exothermic reactions  Date: 10/24/2014  Unit: Chemical Changes

 Copy graphs ΔT Reaction AReaction B

A.What are the chemicals in an ice pack and what type of reaction is it? B.When the narrator starts talking about energetics, what are molecules always doing and how are temperature and movement related? C.How are the attractive forces between molecules related to energy and temperature? D.Why does your cold pack get cold?

 What is happening inside of our cold pack? ◦ What are the steps/sequence ◦ 2 minutes to write your answer  What is happening inside of our hand warmer? ◦ Hand Warmers Hand Warmers

 How can you tell the difference between endothermic and exothermic reactions?

1. Label the following graphs as endothermic or exothermic reactions. 2. Write one sentence explaining how you know each one is endothermic or exothermic. A B

 We learned about ◦ Physical properties and changes ◦ Chemical properties and changes  Reading chemical reactions ◦ Products and reactants ◦ Coefficients and subscripts  Balancing chemical equations  Common outcome of ALL chemical reactions  VSVS on Monday  HW due Tuesday