Week 5 9/29-10/3

The Highlander Sheet  Objective: Use Conservation of Mass to explain a chemical reaction. New WHOT today. (remember your science journals should be out.) Responsibilities: Reactants, products, chemical reaction, physical reaction 9/29

Title: Density vs Pressure  Draw the table to the right…make it take up at least half a page.  Sketch each bottle after the reaction. Note: Watch the mass on the scale. BalloonCap Sketch: Change in Mass:

Observations.  Did you note any change in the shape of the bottle or the balloon? Explain.  1. Did you observe any changes in the antacid tablet or the water? Explain.  2. Was there a difference in the mass of the bottle and its contents after the reaction?  3. What did you see when you removed the cap or balloon and record what you see, hear &/or feel.  4. Did the material that exited the balloon or bottle have any mass? How do you know?

What happened in the bottle?  Was it a physical reaction or was it a chemical reaction?  How do we know?  Lets compare: Make a T chart. And look at the evidence. ChemicalPhysical Rearrangement of atoms in a molecule (breaks or forms bonds) Rearranged molecules but not their bonds

What was in the bottles?  The gas produced was carbon dioxide, the same gas we exhale during breathing. Suppose both the cap and balloon methods captured exactly 50 particles (molecules) of carbon dioxide CO2.  Add 50 “particles” to your sketches of the demonstration.

Lets look at a common reaction: one that’s delicious…  Reactants:  Products:

How we write a chemical equation:  Reactants ----  Products

WHOT question:  Compare and contrast the differences between a chemical and physical reaction.

9/30 The Highlander Sheet  Objective/SWBAT:  Model conservation of mass in a reaction  Responsibilities:  New Vocab: reactivity, reactant, product, yield  Balancing equation practice

Warm up… how much do you remember from last year?  Draw 3 particle diagrams. One of each phase: Solid, liquid, and gas. Each sample should have 10 particles.

Sketch the following in your notebook… It’s called a phase diagram 1. Label the section of the figure that is most likely to represent the temperature and pressure conditions associated with the solid phase of matter. 2. Draw a horizontal line across the phase diagram so that it touches all 3 phases of matter.  Imagine being a particle experiencing the temperatures and pressures indicated by your line. Discuss with your table-partner what you would see and feel from the macroscopic and microscopic viewpoints. Pressure Temperature low high

9/30 Title: What happens in a reaction?  Reminder: Conservation of Mass  Mass can neither be created nor destroyed, but can be changed from one form to another.  What does this have to do with a chemical reaction??  Number of each type of atom present before the reaction (reactants) must be equal to the number of each type of atom present after the reaction (products)  Reactions contain two parts Reactants The starting substances Always on left of equation  Yields Products Substances that are new Formed during reaction

Breaking the code  A chemical equation is a way of describing a chemical reaction using chemical formulas  Symbol for Hydrogen ______  Symbol for Oxygen ______  Subscript ______  Coefficient ______  Chemical bonds hold atoms close to each other to form molecules. 3H2O3H2O H O 2 – describes how many of the H (the atom before it) 3 – describes how many of the H 2 O molecules there are

WHOT QUESTION: WHOT QUESTION: After years of burning candles in your house, explain how the ceiling got coated with smokex.  Hint: use the term: combustion, CO2, H20… and your candle diagrams from today.

10/1 The Highlander Sheet  Objective/SWBAT:  Use models to help understand how to balance chemical equations.  Responsibilities  Diatomic Elements  Test next week! Shooting for Wednesday 10/8

Building Chemical Models Chemical# of Bonding Sites Hydrogen1 Oxygen2 Nitrogen3 Carbon4 Each bonding site needs to be filled!

When ignited, the natural gas methane (CH 4 ), combines with oxygen gas (O 2 ) in the air to produce carbon dioxide (CO 2 ) and water (H 2 O).  Use your atomic ball and stick models to create models of the molecules described in the reaction.  Sketch each molecule below and determine whether it is a reactant or product methane (CH 4 ) oxygen gas (O 2 ) carbon dioxide (CO 2 ) water (H 2 O). Reactant OR Product Reactant OR Product Reactant OR Product Reactant OR Product

Lets make one together… lets try… you guessed it!  New vocab word!  Diatomic elements – H, N,O,F,Cl,Br, or I (lets take a look at where they are…)   So whenever you see an Oxygen or Hydrogen MOLECULE!!! You need to make sure it has a pair (but only if its by itself.

Making of water.

Get done early? Build some complex molecules using the kits and draw them in your journal.  Suggested models:  Ethane  Propane  Butane  Benzene(forget the adding H atoms.)  Ethanol  Adrenaline

Does conservation of mass work so far?  So far we have:  Can add more molecules to balance numbers  Use coefficients as necessary:  CH 4 + 2O 2  CO 2 + 2H 2 O + +  1 carbon (black) 2 oxygen (red) 4 hydrogen (white) 1 carbon (black) 3 oxygen (red) 2 hydrogen (white) + + 

WHOT QUESTION:  Combustion is a type of chemical reaction. What evidence tell you a chemical reaction happened. Responsibilities: Finish any practice problems not previously attempted.

10/2 The Highlander Sheet  Objective/SWBAT:  Start to explain how a Galilean thermometer works.  Differentiate between mass and weight.  Responsibilities  Test next week! (Thursday 10/9)  Finish any balancing chem. Equations from the lab.

When ignited, the natural gas methane (CH 4 ), combines with oxygen gas (O 2 ) in the air to produce carbon dioxide (CO 2 ) and water (H 2 O).  Use your atomic ball and stick models to create models of the molecules described in the reaction.  Sketch each molecule below and determine whether it is a reactant or product methane (CH 4 ) oxygen gas (O 2 ) carbon dioxide (CO 2 ) water (H 2 O). Reactant OR Product Reactant OR Product Reactant OR Product Reactant OR Product

Yesterday’s Lab  Lets look at #3  “Explain why the mass of your candle changed after 2 minutes of combustion, considering the law of conservation of matter and the procedures you used.”  Take a moment to answer the question with your table partner.  -Finished – Take some time to add what you and your partner talked about.  -Not Finished – Write… NOW!!!

Next Week’ Test  Here… This is actually it.  I’m not kidding.  You need to be able to explain this from a macroscopic and microscopic level.  Lets try to understand what’s going on.

Label your Journal “Properties R’ Us”  1. Draw a sketch of the setup at the front.  Label all parts (include beaker scale and weight.)  (mass)  2. Predict what will happen when I lower the mass in the water.  Sketch what you think will happen.  (remember we add why when we predict.)  3. Compare your prediction with your table partner.  4. Sketch what actually happens.

 Did the density of the dangling object change? How do you know?  What happened to the mass and the volume of the object.

WHOT QUESTION:  What makes a substance less dense or more dense. Is there something invisible that can explain density?  Words that may help: Mass, volume, space, particles, atoms  You may want to draw a picture to explain…