1. Carbon TIME Modeling & Explaining Ethanol Burning

2. Entry Task: Which atoms form HIGH Energy Bonds? Which atoms form LOW Energy Bonds?

3. What happens when… An atom leaves a high energy bond and forms a low energy bond? C – C  C -- O

4. Evidence Based Argument Tool Share with a neighbor, compare the evidence you selected to help you answer each question. How are your ideas alike? How are your ideas different? Compare your claims How are they alike and different?

5. About Evidence Mass provides good evidence to answer the Movement question BTB evidence provides only a partial answer to the Carbon question. We know Carbon ends up in CO2 detected by the BTB We DON’T know where the carbon came from in the ethanol The observation of heat and light in the flame also provide only a partial answer to the Energy question We know that energy is released We DON’T know where the energy came from

6. Making the Reactant Molecules: Ethanol and Oxygen The flame of burning ethanol comes when ethanol (C 2 H 5 OH) reacts with oxygen (O 2 ). 1.Make a molecules of ethanol and oxygen on the reactant side of your Molecular Models Placemat. 2.Use twist ties to represent energy. 3.Use the Forms of Energy cards to show which form of energy the twist ties represent. Follow along with your worksheet… Read Part A Complete steps B.1a-d 6

7. 7 Oxygen Carbon Dioxide Water Ethanol What’s the hidden chemical change when ethanol burns? ?

8. How Atoms Bond Together in Molecules Atoms in stable molecules always have a certain number of bonds to other atoms: Carbon – Oxygen – Hydrogen – Oxygen atoms do NOT bond to other oxygen atoms if they can bond to carbon or hydrogen instead. Chemical energy is stored in bonds between atoms 8

9. 9 Photo of reactant molecules: C 2 H 5 OH (ethanol) and O 2 (oxygen) Start by making the molecules and energy units of the reactants and putting them on the reactants side, then rearrange the atoms and energy units to show the products. Remember: Atoms last forever (so you can rearrange atoms into new molecules, but can’t add or subtract atoms). Energy lasts forever (so you can change forms of energy, but energy units can’t appear or go away) ReactantsProducts Chemical change Ethanol Oxygen

10. Important: When you are finished constructing the reactants, put all extra pieces away. 10

11. Rearranging the Atoms to Make Product Molecules: Carbon Dioxide and Water The flame of burning ethanol comes when ethanol (C 2 H 5 OH) reacts with oxygen (O 2 ) to produce carbon dioxide (CO 2 ) and water (H 2 O). Show how this can happen: Follow along on your worksheet… Complete steps B.2.a-c 11

12. 12 Photo of product molecules: CO 2 (carbon dioxide) and H 2 O (water) Start by making the molecules and energy units of the reactants and putting them on the reactants side, then rearrange the atoms and energy units to show the products. Remember: Atoms last forever (so you can rearrange atoms into new molecules, but can’t add or subtract atoms). Energy lasts forever (so you can change forms of energy, but energy units can’t appear or go away) Reactants Products Chemical change Water Carbon dioxide

13. 13 Comparing photos of reactant and product molecules Start by making the molecules and energy units of the reactants and putting them on the reactants side, then rearrange the atoms and energy units to show the products. Remember: Atoms last forever (so you can rearrange atoms into new molecules, but can’t add or subtract atoms). Energy lasts forever (so you can change forms of energy, but energy units can’t appear or go away) Reactants Products Chemical change Ethanol Oxygen Water Carbon dioxide

14. Reactants Products Chemical change What happens to atoms and energy when ethanol burns? Ethanol Oxygen Water Heat and light energy Carbon Dioxide

15. Reactants Products Chemical change Ethanol Oxygen Water Heat and light energy Carbon Dioxide What happens to carbon atoms when ethanol burns? Carbon atoms in ethanol become part of carbon dioxide molecules.

16. Reactants Products Chemical change Ethanol Oxygen Water Heat and light energy Carbon Dioxide What happens to oxygen atoms when ethanol burns? Oxygen atoms become part of carbon dioxide and water molecules.

17. Reactants Products Chemical change Ethanol Oxygen Water Heat and light energy Carbon Dioxide What happens to hydrogen atoms when ethanol burns? Hydrogen atoms become part of water molecules.

18. Reactants Products Chemical change Ethanol Oxygen Water Heat and light energy Carbon Dioxide What happens to chemical energy when ethanol burns? Chemical energy is transformed into heat and light energy.

19. Reactants Products Chemical change What happens to atoms and energy when ethanol burns? Ethanol Oxygen Water Heat and light energy Carbon Dioxide Atoms last forever! Energy lasts forever!

20. Writing a Chemical Equation Chemists use chemical equations to show how atoms of reactant molecules are rearranged to make product molecules. Writing the equation in symbols. Chemists use an arrow to show how reactants change into products. Equations must be balanced. Remember: Atoms last forever. Try it: Can you write a balanced chemical equation to show the chemical change when ethanol burns? 20

21. 21 Chemical equation for ethanol burning C 2 H 5 OH + 3O 2  2 CO 2 + 3 H 2 O (in words: ethanol reacts with oxygen to yield carbon dioxide and water)

22. Finish What Happens when Ethanol Burns: Complete “Molecular Models for Ethanol Burning Worksheet Part C & D Complete “Explanation Tool: What happens when ethanol burns?” Combine everything you learned about what happens when ethanol burns into one explanation Consider evidence from the investigation and observations from the modeling activity (15 Minutes)

23. Molecular Modeling: Methane Burning You can use what you know about Ethanol burning to explain many other molecules burning too! Same Rules for Atoms and Energy Apply

24. 24 The bottom of flame at atomic-molecular scale Oxygen Carbon Dioxide Water Methane Nitrogen

25. 25 The top of flame at atomic-molecular scale Oxygen Carbon Dioxide Water Methane Nitrogen

26. 26 What happened between the bottom and the top of the flame? Bottom of the flame Top of the flame Oxygen Carbon Dioxide Water Methane Nitrogen

27. 27 Oxygen Carbon Dioxide Water Methane What’s the hidden chemical change when methane burns? ?

28. Always answer the 3 Qs Whenever you explain a chemical change (reaction) Use the next slide to help you practice answering the 3 Qs for Methane Burning

29. Three Questions Poster 29 QuestionRules to FollowConnecting Atoms to Evidence The Movement Question: Where are atoms moving? Where are atoms moving from? Where are atoms going to? Atoms last forever in combustion and living systems. All materials (solids, liquids, and gases) are made of atoms. When materials change mass, atoms are moving. When materials move, atoms are moving. The Carbon Question: What is happening to carbon atoms? What molecules are carbon atoms in before the process? How are the atoms rearranged into new molecules? Carbon atoms are bound to other atoms in molecules. Atoms can be rearranged to make new molecules. The air has carbon atoms in CO 2. Organic materials are made of molecules with carbon atoms: foods fuels living and dead plants and animals. The Energy Question: What is happening to chemical energy? What forms of energy are involved? How is energy changing from one form to another? Energy lasts forever in combustion and living systems. C-C and C-H bonds have more stored chemical energy than C-O and H-O bonds. We can observe indicators of different forms of energy: organic materials with chemical energy light heat energy motion.

30. Making the Reactant Molecules: Methane and Oxygen Read Part A Complete Part B.1a-c Put ALL extra pieces away!!! Then check your work with Ms KL before continuing 30

31. 31 Photo of reactant molecules: CH 4 (methane) and O 2 (oxygen) Start by making the molecules and energy units of the reactants and putting them on the reactants side, then rearrange the atoms and energy units to show the products. Remember: Atoms last forever (so you can rearrange atoms into new molecules, but can’t add or subtract atoms). Energy lasts forever (so you can change forms of energy, but energy units can’t appear or go away) ReactantsProducts Chemical change Oxygen Methane

32. Important: When you are finished constructing the reactants, put all extra pieces away. 32

33. Rearranging the Atoms to Make Product Molecules: Carbon Dioxide and Water Complete Steps B.2.a-c Check with Ms KL before continuing Complete Steps C & D 33

34. 34 Photo of product molecules: H 2 O (water) and CO 2 (carbon dioxide) Start by making the molecules and energy units of the reactants and putting them on the reactants side, then rearrange the atoms and energy units to show the products. Remember: Atoms last forever (so you can rearrange atoms into new molecules, but can’t add or subtract atoms). Energy lasts forever (so you can change forms of energy, but energy units can’t appear or go away) ReactantsProducts Chemical change Water Carbon dioxide

35. 35 Comparing photos of reactant and product molecules Start by making the molecules and energy units of the reactants and putting them on the reactants side, then rearrange the atoms and energy units to show the products. Remember: Atoms last forever (so you can rearrange atoms into new molecules, but can’t add or subtract atoms). Energy lasts forever (so you can change forms of energy, but energy units can’t appear or go away) ReactantsProducts Chemical change Water Carbon dioxide Oxygen Methane

36. Reactants Products Chemical change What happens to atoms and energy when methane burns? Methane Oxygen Water Heat and light energy Carbon Dioxide 36

37. Reactants Products Chemical change Oxygen Water Heat and light energy Carbon Dioxide What happens to carbon atoms when methane burns? Methane Carbon atoms in methane become part of carbon dioxide molecules. 37

38. Reactants Products Chemical change Oxygen Water Heat and light energy Carbon Dioxide Methane What happens to oxygen atoms when methane burns? Oxygen atoms become part of carbon dioxide and water molecules. 38

39. Reactants Products Chemical change Oxygen Water Heat and light energy Carbon Dioxide Methane What happens to hydrogen atoms when methane burns? Hydrogen atoms become part of water molecules. 39

40. Reactants Products Chemical change Oxygen Water Heat and light energy Carbon Dioxide Methane What happens to chemical energy when methane burns? Chemical energy is transformed into heat and light energy. 40

41. Reactants Products Chemical change What happens to atoms and energy when ethanol burns? Ethanol Oxygen Water Heat and light energy Carbon Dioxide Atoms last forever! Energy lasts forever! 41

42. Writing a Chemical Equation Chemists use chemical equations to show how atoms of reactant molecules are rearranged to make product molecules Writing the equation in symbols: Chemists use an arrow to show how reactants change into products: [reactant molecule formulas]  [product molecule formulas] Saying it in words: Chemists read the arrow as “yield” or “yields:” [reactant molecule names] yield [product molecule names] Equations must be balanced: Atoms last forever, so reactant and product molecules must have the same number of each kind of atom Try it: can you write a balanced chemical equation to show the chemical change when methane burns? 42

43. 43 Chemical equation for methane burning CH 4 + 2O 2  CO 2 + 2 H 2 O (in words: methane reacts with oxygen to yield carbon dioxide and water)

44. Homework: Complete “Molecular Models for Methanol Burning Worksheet Part C & D” Complete “Explanation Tool: What happens when Methanol burns?” Combine everything you learned about what happens when methanol burns into one explanation Consider evidence from the investigation about ethanol and observations from the methanol modeling activity