Friday, October 29, 2010


Today students took a mole challenge to see how much they knew about moles... besides their favorite number. The high score was a 9.5/10 so I must have stumped them. They did do better than they thought they would... and most of them were a bit mad when they saw what the answers were to the ones they didn't know.

For moles there are basically three conversions to know.
1 mole
6.02 x 10^23

1 mole
(molar mass) grams (add weights from PT)

1 mole
22.4 Liters

Today we learned about Avogadro's theory about gases and then practiced converting using our new favorite number, 22.4. Avogadro, that handsome devil, did a lot of important stuff with moles and is also the guy who gave us our other favorite number 6.02.

Thursday, October 28, 2010


Today, we started talking about moles. Moles are used to count atoms. There are 22,000,000,000,000,000,000 quintillion atoms in a grain of sand and even counting grains of sand is a pain. Because atoms are so tiny, we use the mole to estimate.

There are 6.02 x 10 ^23 molecules in one mole. That's a whole lot. This is our new favorite number because it needs to be memorized. We practiced converting from moles to molecules.

Next we discussed molar mass. Molar mass = 1 mole and it also equals atomic mass from the periodic table. To find the molar mass of carbon dioxide you find the mass of carbon and two oxygens and add them together. Finding molar mass is not difficult unless the molecule has tricky subscripts (which we have been practicing).

Friday, October 22, 2010

Mole Day Festivities

Mole Day festivities were started on October 22, because we aren't going to be at school on the true Mole Day of October 23.

Students did a mix of goofy things and actual chem-mole-stry math problems. Activities included the mole hunt to see if they could find the 27 moles hidden in my room, pin the nose on the mole, and coloring a famous mole celebrity like the Little Mole-mid, Mole-ky Mouse, Mole-y Cyrus, and other funny ones.

Students also learned how to calculate molar mass and how to do a few mole conversions. In 4th period, Katelin scored the most points, followed by her partner Sam in second, and Josh in third.

Friday, October 15, 2010

Reaction Rates

Reaction Rates are affected by a few things. Without telling them the point, the students had a quick demo where they had to dissolve sugar cubes the fastest. 

In third period, Taylor K was the quickest and in fourth, Maria and Sam were the fastest. The key was to use warm water (I only have one warm sink and they were def fighting over it or trying to remember which one it is) - or chew them up and spit them out. 

The things that speed up reactions are:
  • Temperature - warmer is faster
  • Surface Area - small pieces have more surface area
  • Concentration - the more water, the faster sugar will dissolve
  • Catalyst - lowers the activation energy and speeds up the reaction
  • Agitation - shaking or stirring increases the frequency of collisions.
Lucas is using scissors to bust up his sugar cubes and make the pieces smaller. Josh is looking for the warm sink

Le Chatlier

Today students learned about reaction rates and how to increase them. They also learned about reversible reactions and how Le Chatlier's principle influences shifts of equilibrium in reversible reactions.

Basically as you apply a stress to a system, the system will shift in response to the stress. If you add one of the molecules it will shift away from that molecule. If you take away a molecule, it will shift towards it to make more. Heat works the same way.

Pressure is the tricky one. If pressure is applied to an equilibrium, then the reaction will shift to the side that has the least amount of molecules (count the coefficients).

We finished class by reviewing concepts about bonding and naming in preparation of Monday's benchmark.
Homework: finish Orange Benchmark Review Sheet

Thursday, October 14, 2010

We started by talking about the simple definition of the terms, what the probably products and reactants are and went over a basic formula for the reaction types the students need to be familiar with.

Reaction Types include:
  • synthesis
  • decomposition
  • singe replacement
  • double replacement
  • combustion
  • endothermic
  • exothermic
  • oxidation-reduction
  • neutralization
After discussing the basics, we drew cartoons of stick men and women going on dates to show how atoms move around in the simpler reactions. The picture posted is someone else's version of single replacement (see the one guy switches with the other) (I would take a photo, but my camera is out of commission at the moment). For more help with this, check here.

 Homework is the front of the orange Benchmark Review Sheet

Monday, October 11, 2010

Balancing Equations

Students are learning to balance equations. Today they learned that reactants are what you start with and are on the left side of the equation. Products are on the right side of the arrow and are what is made by process of a chemical change.

Because of the Law of Conservation of Mass, the number of atoms have to be equal on both sides. To balance an equation, the coefficients are changed. Coefficients are the big numbers in front that tell you how many molecules there are. The subscripts (the little lower numbers) are not allowed to be changed because those are there to make neutrally bonded molecules (what we learned in the last unit.

By changing the coefficients and counting the number of atoms on both sides of the arrow, balancing can be achieved.

Monday, October 4, 2010

Bonding and Naming

Sorry to not be posting, I have been busy teaching bonding and naming. There are two basic types of bonds and each requires a separate set of rules. I taught one then the other and students got it perfectly. However, when you mix them together and they have to decide which method to use, it somehow gets mixed up.

If it is a + and -, the bond is ionic. The electrons are given and taken in the bond. To get the formula, you criss cross the charges. To name it, you say the name of the metal, then the name of the nonmetal with an -ide ending. If it is a metal from DForP block, then you use a roman numeral to indicate the charge of the metal.

If it is a - and -, the bond is covalent. The electrons are shared in the bond. To get the formula, you have to draw the Lewis Dot structures for the elements and connect the dots that don't have friends. You write the formula based on your drawing. To name it, use prefixes to indicate the number of atoms in the formula and the second one ends in -ide. For these it doesn't matter which element comes first.

The test on this material is today. Tonight's homework is to finish the watermelon sheet.