CATALYST (10 minutes, individual work): 1. Counting atoms Assignment 4 Chemical Detectives at the Molecular Level LO: To explain the differences between chemical and physical changes through observable evidence. EQ: What evidence can be used to tell the difference between chemical and physical changes. LEVEL ZERO VOICE CATALYST (10 minutes, individual work): 1. Counting atoms 2. Define: endothermic exothermic physical change chemical change AGENDA Discuss lab Lab Reading exhibition HOMEWORK 1. Finish processing tasks  

Class discussion: How do you know when a chemical reaction has taken place?

Guiding Question: How can I explain the differences between a chemical change and a physical change through observable evidence?   You will be observing several ways in which matter interacts. Your task is to collect evidence to prove whether the interaction demonstrates a physical change or a chemical change.

Now you will be testing the following compounds Sugar C12H22O11 Wax C31H64

Sugar Cubes Rows (1-3) Write observations

Row 1: Crush sugar https://www.youtube.com/watch?v=QCfEVnaIguM

Row 2: sugar in water https://www.youtube.com/watch?v=qc1z84MDKxE

Row 3: burning sugar https://www.youtube.com/watch?v=8gVyaAXKjd4

Row 4: melt wax https://www.youtube.com/watch?v=lK-vMXg0gJs

Row 5: burn candle wick https://www. youtube. com/watch

Now you will be testing the following compounds Vinegar (acetic acid) C2H4O2 Citric acid C6H8O7 Baking soda (sodium bicarbonate) NaHCO3 Cornstarch C6H12O5 Iodine solution I2 Washing soda (sodium carbonate) Na2CO3

Lab safety: These are all household chemicals that you don’t need gloves to handle but you do need goggles because they can’t get in your eyes. Do not get on your skin. Do not ingest. Proper smelling technique

Originally, you were going to design the experiment yourself and determine the amount of each you would test…. We don’t have time so… (class discussion) Vinegar (acetic acid) C2H4O2 Citric acid C6H8O7 Baking soda (sodium bicarbonate) NaHCO3 Cornstarch C6H12O5 Iodine solution I2 Washing soda (sodium carbonate) Na2CO3

Lab safety: These are all household chemicals that you don’t need gloves to handle but you do need goggles because they can’t get in your eyes. Do not get on your skin. Do not ingest. Proper smelling technique

Reaction observations for iodine: Iodine/citric acid: clump together, no reaction Iodine/baking soda: no reaction Iodine/cornstarch: changes color, turns black

We will use the following mixture to highlight what happens at the molecular level: citric acid and washing soda.

C6H8O7 + Na2CO3 → CO2 + H2O + Na3C6H5O7 The mixture between citric acid (C6H8O7) and washing soda (Na2CO3) showed evidence of a chemical reaction.  Scientists write chemical reactions as equations to show what happened before and after.  It makes carbon dioxide, water, and trisodium citrate. Write the chemical equation and label each item with its name (found above): C6H8O7    +  Na2CO3   →   CO2    +  H2O  + Na3C6H5O7

C6H8O7       +    Na2CO3       →   CO2        +     H2O      +    Na3C6H5O7 Reactants Products

Before chemical reaction

After chemical reaction

Cl.Ev.Re.: Prove how you know the citric acid and washing soda mixture produced a chemical change with evidence and reasoning.  Make sure you include the what happens at the molecular level.  You may include labeled diagrams, but you need to explain your ideas in words as well.   Claim: Write your claim. (chem rxn?) Evidence: What is your evidence to support your claim? State evidence without reasoning. List lines of evidence. Reasoning: Explain why your evidence supports your claim.

Desalination Project (phase changes) Final Project Temperature in Reactions (includes Conservation of Mass) Chemical vs Physical Changes (includes Conservation of Mass) Structure of the atom, Isotopes, Valence Electrons

PROCESSING TASK (10 minutes, individual work): Assignment #3 Chemical Detectives at the Molecular Level LO: To be able to draw a molecule given its molecular formula. EQ: Compare and contrast atoms and molecules? LEVEL ZERO VOICE PROCESSING TASK (10 minutes, individual work): Model the chemical reaction for the electrolysis of water. Underneath the diagram, explain in words how you can tell if a chemical reaction has taken place. AGENDA Writing reactions Modeling reactions HOMEWORK 1. Finish processing tasks