Tuesday, November 30, 2010

LapTop Computers Wednesday

Today you will be completing a practice SOL test. You will do this on this computer. You will need a PT, a calculator, and scrap paper. Answer the questions as best you can and use good test taking skills.

DO NOT go back and DO NOT start over. Instead read the questions carefully and make good choices. If you get a question incorrect I will explain it to you, but you need to try the question on your own. Be patient.

Take your time. At the end of the test you will SHOW me your score. If you do not finish, you will show me how many questions you answered and your score. I will record this as a grade.

Tomorrow and Friday you will have other assignments on the computer. You will need to come to to this website, read the post, and follow the directions. You will have directions and various scores to report and turn in. Anyone using a computer inappropriately will be reported and computer privileges will be removed.

Ready for you test. Use this link and get started.

Wednesday, November 24, 2010

Computer Lab Day November 24

If you were absent for acids and bases, these are the links you need. Please do this by Friday.

Today you are going to be testing acids and bases. Please do not waste time and ask questions when you have them.

Monday, November 22, 2010

Acids and Bases

Today we started discussing acids and bases.

Acids have H+ and donate them, they have the smaller numbers 0-6.9, they turn litmus red, and have sour tastes. 

Bases have OH- and want H+ to make water, they have Bigger numbers, they have a pH between 7.1 and 14, they turn litmus Blue, and they taste Bitter. 

If you mix an acid and a base together, then there is a neutralization reaction. A neutralization reaction is also a double replacement reaction. In neutralization, the acid and base combine to form a water and a salt. The water and the salt are neutral (hence the name).

pH measures the concentration or molarity of H (Hydrogen ions) in a solution. That's why the H is capitalized.

pH + pOH = 14. So if you have the pH, it is easy to get the pOH... just subtract from 14. There are some fun interactives for acids and bases linked at the bottom of this webpage. Check out the Alien Juice Bar.

Friday, November 19, 2010

Benchmark III

Today students took Benchmark III, a cumulative benchmark. It was a tough one and there was a little frustration and tension in the room despite the soothing sounds of Bob Marley. However this frustration is justified because the Chemistry SOL is a tough one. Maybe now they will believe it.

Despite frustrations, scores were within the passing range. Congratulation to Sam G for scoring a "Passed Advanced."

Wednesday, November 17, 2010

Combined Gas Law

The combined gas law combines the work of Charles, Boyle, and Gay-Lussac.

nT nT

Basically, memorize one formula and then use only the variables you need, so sometimes you need PV = PV, and sometimes V/T = V/T.

This will help you with placement and deciding whether you should multiply or divide.

Tuesday, November 16, 2010

Ideal Gas Law

Ideal gases do not actually exist, but we pretend they do and use the Ideal Gas Formula of PV=nRT.

One of these variables will not be given to you and you have to solve for it. This does not seem difficult after stoich, so students dove in, did well, and finished early.

Benchmark III (cumulative) is Friday.

Monday, November 15, 2010

Beginning Gases

Today we started learning about the behavior of gases and the factors that affect them. Gases are lightweight fast moving particles that generally have a lot of empty space between them. Because of this, they are easily compressible (pictured left). If not contained, gases can spread (or diffuse) to fill any size and shape container.

Gases are affected by pressure, volume, number of moles, and temperature. Changing any one of these variables, changes all the others.

Today we also learned the formula for the Law of Partial Pressure. Basically partial pressures add up to form total pressure. If the total pressure is given then you subtract the partial pressures.

We are still working on moles and making sure we have stoichiometry down pat.

Friday, November 12, 2010


Today students took their Stoichiometry Test which is all about converting to moles and away from moles and honestly is a lot of math. It's not hard if you pay attention and set it up right, but it takes some practice.

Students must get a perfect score on the front (no errors) or they have to retake it. This seems crazy, but by this point, they all know they can do it, and they want to do it.

We will be starting gases on Monday and taking a cumulative benchmark on Friday.
The week of Thanksgiving we will be covering acids and bases and anything else we need to. Students will have homework over Thanksgiving. After Thanksgiving we have one week to review before the Chemistry SOL on Tuesday December 7th in the afternoon.

Tuesday, November 2, 2010

Bubble Gum!

Students each had a piece of gum and observed the gum by weighing it, drawing it, and smelling it. All the gum was Dubble Bubble, but the Cry Babies were the most popular.

Next the students chewed the gum for ten minutes. While they were waiting we watched How Its Made on bubblegum (the video is linked on the side if you want to check it out). We also had a little fun blowing bubbles.

After ten minutes, students did more observations and re-weighed the gum. The gum weighed less... why? Because the sugar dissolved and was lost. Using this weight difference, students determined the percent composition of sugar in the gum they chewed. They also can convert the grams to moles and determine how many moles of sugar were in the gum.

This lab will be due on Friday.