1. Modeling & Explaining Ethanol Burning
Carbon TIME
Modeling & Explaining Ethanol Burning

2. What do you think happens when methane burns?
Entry Task:
Methane is CH4
What do you think happens when methane burns?
Include answers to the movement, carbon and energy questions in your answer

3. Three Questions Poster
Rules to Follow
Connecting 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 CO2.
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.

4. The bottom of flame at atomic-molecular scale
Credits: Craig Douglas, Michigan State University
Oxygen
Carbon Dioxide
Water
Methane
Nitrogen

5. The top of flame at atomic-molecular scale
Credits: Craig Douglas, Michigan State University
Oxygen
Carbon Dioxide
Water
Methane
Nitrogen

6. 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
Credits: Craig Douglas, Michigan State University K

7. What’s the hidden chemical change when methane burns?
Credits: Craig Douglas, Michigan State University
Oxygen
Carbon Dioxide
Water
Methane

8. Making the Reactant Molecules: Methane and Oxygen
Read Part A Complete Part B.1a-c Put ALL extra pieces away!!! Show Ms KL your Reactants before moving on to part B.2

9. Chemical change Methane Oxygen
Photo of reactant molecules: CH4 (methane) and O2 (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.
Chemical change
Methane
Photo Credit: Michigan State University
Oxygen
Reactants
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)

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

11. 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

12. Water Chemical change Carbon dioxide
Photo of product molecules: H2O (water) and CO2 (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.
Water
Chemical change
Carbon
dioxide
Photo Credits: Michigan State University
Reactants
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)

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.
Water
Chemical change
Carbon
dioxide
Methane
Photo Credits: Michigan State University
3. (Optional) Have students use molecular models and twist ties to show changes in matter and energy. 
Have students continue working in pairs to show how the matter and energy in methane and oxygen can be rearranged into the molecules of the products: carbon dioxide and water. Tell students that the product molecules have no high-energy bonds, so the chemical energy in the methane is transformed into heat and light energy.
Use Slide 6 and the instructions on the worksheet to assist students in constructing a model of the chemical reaction. Have students use the same materials they used to form their reactant molecules to form the product molecules. Tell them to place their products in the appropriate box on the product side of the poster.
Show Slide 7 to let students compare their products to the products in the picture. Have students use new energy cards (heat and light) to indicate what form the energy is in after the chemical change by putting the card under the twist ties.
Show Slide 8 to give students an overview of the entire reaction.
Oxygen
Reactants
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)

14. What happens to atoms and energy when methane burns?
Carbon Dioxide
Methane
Reactants
Chemical change
Credits: Craig Douglas, Michigan State University
Water
Products
Oxygen
Heat and light energy

15. What happens to carbon atoms when methane burns?
Carbon Dioxide
Methane
Reactants
Chemical change
Credits: Craig Douglas, Michigan State University
Water
Products
Carbon atoms in methane become part of carbon dioxide molecules.
Oxygen
Heat and light energy 15

16. What happens to oxygen atoms when methane burns?
Carbon Dioxide
Methane
Reactants
Chemical change
Credits: Craig Douglas, Michigan State University
Water
Products
Oxygen atoms become part of carbon dioxide and water molecules.
Oxygen
Heat and light energy

17. What happens to hydrogen atoms when methane burns?
Carbon Dioxide
Methane
Reactants
Chemical change
Credits: Craig Douglas, Michigan State University
Water
Products
Hydrogen atoms become part of water molecules.
Oxygen
Heat and light energy

18. What happens to chemical energy when methane burns?
Carbon Dioxide
Methane
Reactants
Chemical change
Credits: Craig Douglas, Michigan State University
Water
Products
Chemical energy is transformed into heat and light energy.
Oxygen
Heat and light energy

19. What happens to atoms and energy when ethanol burns?
Carbon Dioxide
Ethanol
Reactants
Chemical change
Credits: Craig Douglas, Michigan State University
Water
Products
Atoms last forever! Energy lasts forever!
Oxygen
Heat and light energy

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: [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?

21. Chemical equation for methane burning
CH4 + 2O2  CO2 + 2 H2O
(in words: methane reacts with oxygen to yield carbon dioxide and water)

22. 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