Lesson 1: Polarity Sort: What Kinds of Molecules are There?
Students will work in small groups to use highlighters to identify atoms as high, middle, or low electronegativity using a chart of atoms electronegativities. Students will then sort the molecules into two piles: polar molecules and non-polar molecules. Students will then share their methods and reasoning with the class, and compare to accepted values.
Lesson 2: Molecule Build: How do I Figure out a Molecule’s Correct Type?
Students will build models of common molecules (like NH
O, HF) in molecular model sets and also with balloons. They will then label the balloon models with the partial positive charges by coloring with a red marker. Label the partial negative charges by coloring with blue marker. Students will then share their models and reasoning with the class.
Lesson 3: Molecular Speed Dating: How do Molecules of Different Types Interact With Each Other?
Each student will take one molecular model that they helped build in their group from Lesson 2. Students will break out into individuals, and “speed date” another molecule for 5 minutes. During that time the dating pair will evaluate the type of molecule they are dating: non-polar covalent, polar covalent, ionic, charged ion; and determine the types of interactions at work between them: London dispersion forces, dipole-dipole, dipole-induced dipole, ionic attraction, ionic repulsion, and hydrophobic effect, and rank the “date” as “terrible”, “okay”, “good”, “great”. After 6 “speed dates”, students will rank each date from best to worst. They will then look at the list of all potential dates and pick the ideal date and the least ideal date. Students will justify their reasoning for each rank and choice. Students will share their methods.
Lower level groups will be provided a chart with the type of molecule each molecule is, and a chart with diagrams and point values for each type of interaction. They will only have to match the molecule to its type from the chart, match it to the type of interaction, add up the points, and rank the molecular date (London dispersion forces = +1, dipole-dipole = +3, dipole-induced dipole = +2, ionic attraction = +5, ionic repulsion = -5, and hydrophobic effect = -5). They will also justify, but will share their reflections instead of methods.
Lesson 4: Molecular Attraction: What is Molecule Attraction/Repulsion Similar to in Real Life?
The teacher will explain and show real life analogies of the behavior of molecules will be given and explained in a lecture format. The students will listen, write notes, discuss, ask questions, and pose their own analogies for the types of intermolecular interactions.
Van der Waals Forces Analogies:
when cars line up on the highway for no reason.
when people line up for no reason.
when people in survival situation movies, they group together. “Safety in Numbers”.
Molecules are attracted to each other in different ways, some stronger attractions than others, but they almost always prefer to be near other molecules than on their own.
Induced Dipole-Induced Dipole Interactions Analogies:
“Books in a Bookcase”: Books always end up together: stacked on a table, shoved in a locker/backpack, stored on a shelf. When they are on a shelf they are all lined up the same way: beginning-end: beginning -end: beginning -end, induced dipole molecules line up the same way (+ -) (+ -) (+ -).
“Parallel Parking”: Cars on the street are always parked parallel from front to back to front to back, or in a parking lot from driver side-passenger side.
Dipole-Dipole Interactions Analogy:
“Besties”. When 2 people who are exactly alike are friends, and they stick together all the time, just like two molecules that are polar covalent.
Dipole-Induced Dipole Interactions Analogies:
“Good-cop/bad-cop.”: The dipole is like the bad-cop, and won’t budge, the other has to be the good-cop, he has to flex a little, and will “help you out”, just like the molecule will temporarily be polarized.
“Frenemies”: When you start acting crazy, but only around your one crazy friend. You are temporarily crazy, just like a molecule is temporarily polarized.
Ionic Bonding Analogy:
“Opposites attract, siblings repel”: Romantic relationships are strongest when personalities complement each other, and siblings are the most romantically repulsive people we know. Ionic bonds can only occur when positives ions and negative ions are nearby each other, positive ions and negative ions repel other alike ions. This is one of the only times molecules would rather be alone than with other molecules. Think about it, would you rather go to prom alone, or with your brother/sister?
Hydrophobic Effect Demonstration:
“Oil & Water”: Everyone knows this example, so this is a demonstration rather than a real life analogy. Show how oils bead up in water in an attempt to get as far away as possible, and show how water does the same thing in a cup of oil. Use a visual aid, drop water in a beaker of oil, and drop oil in a beaker of water.
Lesson 5: Ionic Matchup Game: How do Ions Bond With Each Other?
Students will use refrigerator magnets to make ionic bonding pairs. Note to teachers: Small firm cylindrical magnets are ideal, the flimsy plastic magnets have no discernable poles, and neodymium magnets are too strong. The magnets need to be labeled, half with the (+) on the N side, half with (-) on the S side. This is so the (+) ions will only stick to (-) ions, and will repel other (+) ions, and vice versa. The magnets can be labeled with specific ions, like Na
, etc... , or not. Students will choose a (+) or a (-) ion, and identify which ion it represents. They will then try to make ionic bonding pairs with other students’ ions. Students will write down all pairs that bond to each other.
For each bonding pair, students will write down the charges of each ion, and figure out how many of each positive and negative ion they would need to balance the compound to zero. Students will then write the ionic formula and name for each ionic compound. All compounds will be shared on the board with the class.
Lesson 6: Hydrogen Bonding Game: How Does Hydrogen Bonding Work?
Students will make hydrogen bonds by creating handshakes where there is one and only glove between them, and where each handshake has a left hand shakes a right hand. (gloved left hand + non-gloved right hand = 1 hydrogen bond.)
To illustrate how hydrogens can transfer from one molecule to another, the hands need touch middle fingers like in Figure 1 below. Carefully take the glove off the gloved hand, turn it inside out, put it on the ungloved hand, so that the glove is now inside out and on the other hand.
Figure 1: A photo of a left hand, mirrored for demonstration purposes. Retrieved:https://commons.wikimedia.org/wiki/File:Paume_de_main.jpeg#/media/File:Paume_de_main.jpeg
Lesson 7: Miscibility Lab: What’s Miscible With What?
Students will be given samples of oil, alcohol, water, salt, sugar, and petrolatum, along with the name, chemical formula, and type of molecule (polar, non-polar, ionic). Students have to mix each solid with each solvent, and each solvent with each other. Students will observe and record whether each pairing is able to mix. Students will then write rules for miscibility, and predict the outcomes of pairs of compounds based on their name, and formula.
Lesson 8: Soap Lab: How do I Make Soap?
Students will blend melted coconut oil with a solution of sodium hydroxide (lye) to make small bars of coconut oil based soap. Students will write the chemical equation with diagrams for saponification to release fatty acids from the coconut oil: lauric acid, and any of the other fatty acids. Saponification of the triglycerides in coconut oil will be done together as a model. Lauric acid is the most prevalent in coconut oil.
Lauric acid + sodium hydroxide -> sodium laurate + water.
It is vital to make sure students understand and can explain why a water is produced and not a glycerol. This is because the fatty acids in coconut oil are carboxylic acids, and do not have a functional group on the other side of the carbonyl carbon.
The Hydrogen that exists there bonds to the OH
to produce water. It is also useful to discuss oleic acid’s saponification because it is a component of linseed oil which will be used in Lesson 10.
Lesson 9: Pre-lab Inquiry: What Ingredients of Lake Paints Can Mix With Each Other?
Students will use what they learned in Lesson 7 to develop a plan to test how the components of Lake paints interact with each other. In small groups they will develop a plan to test the miscibility of linseed oil, water, pigments, and aluminum potassium sulfate. Once the plan is developed and students are clear on what they want to test, how they will test it, and proper safety precautions, they will run their tests, analyze their results, and explain how the components of a lake paint are able to mix together.
Lesson 10: Paint Making Lab: How do I Dissolve the Pigment to Make a Lake Paint?
Students will plan a method of making lake paint using their knowledge of the ingredients, and what they learned from Lessons 7, 8, and 9. They have the same ingredients as Lesson 9, as well as solubility data, and suggested starting amounts based on an existing recipe for Madder Lake paint.
Ingredients: linseed oil, water, pigment, potassium aluminum sulfate to make lake pigment paint.
When ready with a method, and safety precautions, students will make lake paint, and try it out. Students can then share their lake paints with each other to create color palettes, and create small paintings. Students will evaluate which paints work the best, compare methods, share data and observations, and will write conclusions and reflections on the project.