1. You learned that chemistry involves 3 areas of focus: Building blocks, Force/Energy, and math. Let's say you are teaching your little girl how to make a cake. You will explain it to her using these 3 areas of focus.

1a: What building blocks will you mention that make a cake?

1b: What force or energy aspects will you mention?

1c: What math is involved in making a cake?

2. Building blocks:
Here is a progression of molecules that starts with one carbon going up to six carbons. Each carbon has a hydroxyl group (OH). The smallest molecule is methanol (a racing fuel) has four hydrogen atoms (H), one carbon (C), and one oxygen (O). The next is ethylene glycol (car antifreeze). The next four are often used as artificial sweeteners. There's a group of 4 atoms that is the basic building block for all of these molecules.
2) What is that group of 4 atoms? (multiple choice answers below)
a) CH3
b) CH2O
c) C2H4O
d) Methanol

4. Force and Energy: Here are three compounds from #2. Let's focus on the force and energy aspects. You've heard of the states of gas, liquid, and solid. The reason for these states is the force of attraction between the atoms or molecules. The stronger the attraction, the more likely it becomes a solid. Methanol becomes a vapor (a gas) very readily. Ethylene glycol stays a liquid even when hot. Mannitol is a solid.
4. All of these can be turned into a vapor (gas). Which one do you think would take the most energy (most heat) to turn into a vapor?

5. Math:  Here are the compounds from #2. Now we are using math to better understand these compounds.
The melting point of a compound reflects how strong the molecules are held together. The stronger they are held together the more heat is required to shake them enough so they will break loose from each other (that's the melting point).
5a. Which one of these compounds in the list has the weakest force holding them together?
5b. Which one has the strongest force holding the molecules together?
5c. The pattern seems to be... the longer the carbon chain, the higher the melting point. There is one exception here. Which one?

6. Building block: This molecule is called iron porphyrin. It's very similar to the molecule in hemoglobin. The "heme" in hemoglobin is referring to a molecule almost like this one. The green spheres here are carbon atoms. The blue ones are nitrogen atoms, and the small white ones are hydrogen atoms. In the center is iron (pink atom). The major building block for this molecule is a five atom ring (4 carbons[green] and 1 nitrogen[blue]). This 5 atom ring is called a "pyrrole". These are bridged to each other using one carbon atom with a hydrogen atom. One of these groups is circled.  The molar mass of this one group of 5 carbon atoms, 3 hydrogen atoms, and 1 nitrogen atom is 77.0845 grams per mole.  The molar mass the iron atom in the center is 55.8452 g/mol.  6. What the molar mass of the whole molecule?

For students in Phoenix College's CHM151 class, send your answers to me (Ken Costello) at chm151@chemistryland.com