Systems and Scale How systems depend on CARBON

Systems and Scale How systems depend on CARBON and CHEMICAL ENERGY

Lesson 5 Activity 1 Explaining what happens when methane burns.

Three Questions Poster Question Rules to Follow Evidence to Look For The Movement Question: Where atoms moving? Where atoms moving from? Where 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

What happens when methane burns? Where atoms moving to? Where atoms moving from? Chemical change What molecules are carbon atoms in before the change? What other molecules are involved? What forms of energy are in the reactants? What molecules are carbon atoms in after the change? What other molecules are produced? What forms of energy are in 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)

Making the Reactant Molecules: Methane and Oxygen The flame of burning methane comes when ethanol (CH 4) reacts with oxygen (O 2). Make a molecules of methane and oxygen on the reactant side of your Molecular Models poster: 1. Get the atoms you will need to make your molecules. Can you figure out from the formula for methane how many C, H, and O atoms you will need? 2. Use the bonds to make models of an ethanol molecule (CH 4) and at least 2 oxygen molecules (O 2, with a double bond) 3. Identify the high-energy bonds (C-C and C-H) by putting twisty ties on them. How many high energy bonds does a molecule of methane have? 4. Compare your molecules to the pictures on the next slide. Are they the same?

Photo of reactant molecules: Methane 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 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)

Rearranging the Atoms to Make Product Molecules: Carbon Dioxide and Water The flame of burning methane comes when methane (CH 4) reacts with oxygen (O 2) to produce carbon dioxide (CO 2) and water (H 2 O). Show this can happen: 1. The heat of the flame breaks the bonds in the molecules, so their bonds can break. Now they can recombine into carbon dioxide (CO 2) and water vapor (H 2 O). Make as many of these molecules as you can from one methane molecule and oxygen. 2. Figure out numbers of molecules: a) • • 1. b) How many O 2 molecules do you need to combine with one methane molecule? How many CO 2 and H 2 O molecules are produced by burning one molecule? Remember, atoms last forever. So you can make and break bonds, but you still need the same atoms. Remember, energy lasts forever. What forms of energy do the twisty ties represent now? Compare your molecules to the pictures on the next slide. Are they the same?

Photo of product molecules CO 2 and H 2 O (carbon dioxide and 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. Chemical change 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)

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. Chemical change 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)

Writing a Chemical Equation • Chemists use chemical equations to show atoms of reactant molecules are rearranged to make product molecules • Writing the equation in symbols: Chemists use an arrow to show 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?

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

What happens when ethanol burns? Where atoms moving to? Where atoms moving from? Chemical change What molecules are carbon atoms in before the change? What other molecules are involved? What forms of energy are in the reactants? What molecules are carbon atoms in after the change? What other molecules are produced? What forms of energy are in 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)

Lesson 5 Activity 2 Finding Organic and Inorganic Materials

Driving question Why do some things burn and other things do not burn? Why does ethanol behave more like wood than water?

Why does ethanol behave more like wood than water?

What we see… Macroscopic Scale ETHANOL WATER WOOD

Zooming out… Large Scale WATER (ocean and cloud) WOOD (Forest) Petroleum

Zooming in… Microscopic Scale WATER (a single droplet) WOOD CELLS ETHANOL (a single droplet)

Zooming in… Atomic-molecular Scale Water molecule (H 2 O) Ethanol molecule (C 2 H 6 O) Cellulose (C 6 H 10 O 5)m ( wood is a mixture of many large and small molecules, including cellulose)

What ATOMS are found in these materials? Water molecule (H 2 O) Ethanol molecule (C 2 H 6 O) Cellulose (C 6 H 10 O 5)m

What ATOMS are found in these materials? ATOMS FOUND IN EACH MOLECULE: Water: Hydrogen, Oxygen Ethanol: Hydrogen, Oxygen, Carbon Water molecule (H 2 O) Ethanol molecule (C 2 H 6 O) Wood: Hydrogen, Oxygen, Carbon Cellulose (C 6 H 10 O 5)m

What BONDS are found in these materials? Water molecule (H 2 O) Ethanol molecule (C 2 H 6 O) Cellulose (C 6 H 10 O 5)m

What BONDS are found in these materials? BONDS FOUND IN EACH MOLECULE: Water: H-O Ethanol: H-O, C-H, C-C Water molecule (H 2 O) Ethanol molecule (C 2 H 6 O) Wood: H-O, C-H, C -C Cellulose (C 6 H 10 O 5)m

What BONDS are found in these materials? Chemical Energy found in the bonds of molecules. C-C and C-H bonds means molecules have usable chemical energy. Water molecule (H 2 O) Ethanol molecule (C 2 H 6 O) So which materials have chemical energy? Cellulose (C 6 H 10 O 5)m

What makes something organic? ORGANIC AND INORGANIC MATERIALS

Materials That Burn Materials That Do NOT Burn WATER PROPANE SALT CARBON DIOXIDE WOOD BUTANE OXYGEN NITROGEN ETHANOL

What makes these burn? How are these different? WATER PROPANE SALT CARBON DIOXIDE WOOD BUTANE OXYGEN NITROGEN ETHANOL

Water, Ethanol, and Wood Ethanol is chemically similar to wood ETHANOL WATER WOOD

MATTER AND ENERGY • Every molecule has both ATOMS and BONDS ATOMS TELL YOU ABOUT MATTER BONDS TELL YOU ABOUT ENERGY

ORGANIC --means the molecule has C-C and C-H bonds INORGANIC --means the molecule does not have C-C and C-H bonds

What Makes Up Living Things? Average Human Water Average human Average apple Average chicken Average Apple Protein Fat Minerals 60% Carbohydrate 1% 15% 23% <1% 85% 14% 0. 5% <1% 62% <1% 30% 8% <1% Inorganic: Water, minerals; Organic: carbohydrates, fats, proteins Average Chicken

Lesson 5 Activity 3 Explaining burning of other materials

Burning materials Methane Butane Propane Ethanol Octane