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  • 1. Conservation of MassFebruary 26th, 2013

2. Agenda1) Warm-up -15 min2) Set up C-notes and Vocabulary cards 15 min3) Candle demonstration and Questions 20 min4) Conservation of Mass Activity 30 min5) Notes & answer FQ 20 minNo homework 3. Warm-upPlease answer these questions on the next blankpage in your notebook1) What is a physical change?2) What is a chemical change?3) Give one example of a physical change andone example of a chemical change 4. Set up your notebooksPlease set up your C-notes for today (next blankpage)Topic: Conservation of MassFocus Question: Where do the atoms in theproducts of a chemical reaction come from? 5. VocabularyMr. Lee will now show you how to set up yourvocabulary cards 6. DemonstrationObserve the demonstration given by Mr. Lee andfill out your worksheet as you go along. 7. Physical ChangeAs we have learned before, in a physicalchange, a new substance is not formed.Ex: When ice turns into liquid water, and then intogas, the substance is still water. No newsubstances are formed. 8. Chemical ChangeIn a chemical change, atoms in the reactants willrearrange and form new bonds, creating products that are new substances.The process by which a chemical change occursis called a chemical reaction. 9. In most chemical reactions, two or moresubstances (reactants) interact to create different substances called products. Lets see a demonstration.. 10. A chemical reaction keeps the candle burning.What are the reactants in the chemical reaction? Oxygen and Wax 11. What are the products in the chemical reaction? Carbon dioxide and water vapor 12. What do you think will happen if a jar is placedover the candle?Why did the flame go out?Where does the wax go? Does it disappear? 13. Wax is made of long polymers called paraffin.Paraffin is a hydrocarbon, which means it is amolecule consisting of only Carbon andHydrogen.The simplest hydrocarbon is Methane (CH4). Wewill use methane to demonstrate how anyhydrocarbon burns. 14. Burning hydrocarbons Answer these questions with your elbow partner. 1) What are the molecules on the left side of the arrow called? The right side? 2) How many Carbon, Oxygen, and Hydrogen atoms are on the left side of the arrow? 3) Where do the atoms on the right side of the arrow come from? 15. You will now make a model to show how atoms inthe reactants rearrange to form the products You will have twenty minutes to complete thisactivity 16. NotesReactants are substances you start with thatinteract and form new substances.Products are the new substances that areproduced from a chemical reactionA chemical equation shows reactants formingproducts by an arrow 17. The Law of Conservation of Mass states thatatoms cannot be created or destroyed. The atomsin the reactants rearrange and form new bonds toform the molecules in the products.This means youre breathing in the same oxygenatoms as Einstein did! 18. Answer Focus QuestionFocus Question: Where do the atoms in theproducts of a chemical reaction come from? 19. Agenda: February 27thToday we will review chemical reactions and physical vs chemical change then find out what are the common signs that achemical reaction has occurred as we prep for ourlab on Friday Copy only the agenda below 1) Define Chemical Reaction 2) Chemical vs Physical Change 3) 6 Signs of Reactions 4) Vinegar & Baking Soda! 20. Today we will review chemical reactions and physical vs chemical changeand find out what are the common signs that a chemical reaction has occurred! 21. Please write these in the Cornell notes you set upyesterdayThe common signs that a reaction has occurredare: (the sense used is listed in parentheses)1) Change of color (sight)2) Change in temperature (touch)3) Flash of light (sight)4) Sound (hear)5) Formation of bubbles (gas) (sight)6) Formation of a precipitate (sight)We will define precipitate later in our unit. 22.