Due to a building evacuation (which was necessary according to protocol but which was precipitated by a hoax) we had to cancel our class. I will make the necessary adjustments to the syllabus and post the changes sometime this evening. In the meantime please enjoy your halloween holiday and study for the quiz – which will be given on Wednesday. The building is open now and all classes are proceeding as scheduled.

The quiz on Wednesday will conver periodic trends and Lewis Dot Structures. Know about atomic and ion size trends so that you can put atoms/ions in order by size. Know about ionization energy trends. Know how to write Lewis Dot Structures.

This homework sheet is very important! Be sure to go over it. http://justonly.com/chemistry/chem201/students/handouts/lewis_practice01.pdf

I’ve created a new handout summarizing the rules for assigning oxidation numbers to the atoms in chemical compounds. Chemistry 203 students should use this for review. It will be very important to have the rules memorized before beginning electrochemistry.

I am posting this message to let you know I will be in my office Monday morning – but there won’t be a scheduled study group. You are welcome to come on by if you have any questions – I’ll be working on grading and the usual organizing of paperwork. Lab notebooks are due on Monday so if you have any questions about your notebooks that  would be another reason to drop by and see me. Enjoy your weekend and think about chemistry!

And please enjoy this phenomenal gallery: http://www.asylumresearch.com/Gallery/Gallery.shtml

The latest issue of Journal of Chemical Education contains a fun puzzle that will help you learn the names of the chemical elements and the names of the bones.

Download Activity

This activity is from: http://pubs.acs.org/doi/abs/10.1021/ed200231g

I will be holding a small group study session in my office on Monday morning from 9:30 until 11:30. The session will focus on the following topics:

1. solving problems related to any of the gas laws (bring the problem you wish to see solved to the study session)

2. practice using the equations λ=c/ν and E=hν

3. practice writing electronic configurations for ANY atom – not just the easy ones (1s²2s² etc.)

All are invited! Hope to see you there.

A second boot camp evening will be scheduled for November 30th, 2011. This boot camp will also give students a chance to raise quiz scores. More details about topics covered will be provided soon.

This local event is well worth attending:

http://www.iit.edu/csl/phy/lederman_lecture

I want to give students who are struggling because of lack of preparation for this course a chance to show what you’ve learned since we started. Wednesday November 2nd is a proposed date for a boot camp experience. We would begin at 6 PM, go over Chapters One and Two step by step. At the end of the review students would be able to take a new version of quiz one and quiz two! We would end by 9:30 PM. It won’t be easy – you must learn this material – but it just might raise your quiz grades and it is a good way to stay in shape for the final exam. Let me know if you plan to attend.

A video from Myth Busters… It should be possible we just need to build a better boat!

http://www.youtube.com/watch?NR=1&v=KReTvW7BTHQ

Please watch this video from NOAA about Ocean Acidification – there is much chemistry to be learned here.

We will meet from 9 am until 11 am in my office. The topic will be “Preparation for the Quiz on Gas Laws”.

Please try this virtual experiment: http://jersey.uoregon.edu/vlab/Piston/

The quiz on Monday will cover three types of problems: PV=nRT problems, P1V1/T1=P2V2/T2 problems and gas density problems. This quiz will also ask you to describe two gases of your choice from this list:

carbon dioxide
sulfur dioxide
hydrogen
helium
oxygen
nitrogen dioxide
ammonia
carbon monoxide
methane
chlorine

In your description I will want you to tell me something about the chemical properties and physical properties of the gas. Does it have an odor? Does it have a color? Is it chemically reactive – an acidic gas, a basic gas? Is it important in the environment? What is its chemical formula? What is interesting about this gas?

This morning when I woke up I couldn’t wait to go out and look at the remains of last night’s fire. Some amazing chemistry takes place when wood burns.

All the big wooden logs are gone. What is left is black and gray. A tremendous amount of energy has been produced, enough to keep ten people warm all evening on a cool (40s fahrenheit) night. There is no sign of incandescence now. But there is still beauty. Let’s look closer.

Beneath the grating we can see lumps and powder. The lumps are black the powder is gray but on closer inspection the powder appears to be white and black particles mixed together.

I gathered up the coals and ashes and put them into a plastic bag and brought them into the house. Next I used a colander to separate the lumps from the powder.

This wood ash contains ten times more potassium than sodium. It can be used to make potassium hydroxide – a kind of lye. My next step is to dissolve all of this ash into boiling water, pour it through a filter (hot filtration), and evaporate most of the water. (I’ll do this in the laboratory and share the results on a future post.) This will produce a solution of mostly potassium carbonate. The carbonate can be precipitated with calcium hydroxide (slacked lime). This will form calcium carbonate solid that can be filtered out leaving a supernantant of potassium hydroxide.  This “lye” can be used to make soap. http://www.grannyslyesoap.com/index.html

Charcoal

Here is the charcoal. The word char-coal tells us that this is coal formed from the charring (burning) of something. Charcoal formed this way is very soft. And it still has a lot of potential energy. The gases have been removed but charcoal will burn. It burns hotter than wood and with very little smoke. This is what we typically buy for our charcoal grills. Charcoal can also be used to draw on paper – paper is made of cellulose from wood. But that’s another story…

charcoal drawing

Tonight I sat out in my backyard with my family and friends and we watched a fire burn. It amazes me how easy it is to become mesmerized by fire – it changes constantly as the logs burn down to ashes. But what is fire?

According to Wikepedia:

Fire is the rapid oxidation of a material in the chemical process of combustion, releasing heat, light, and various reaction products.^[1] The flame is the visible portion of the fire and consists of glowing hot gases. If hot enough, the gases may become ionized to produce plasma.^[2] Depending on the substances alight, and any impurities outside, the color of the flame and the fire’s intensity will be different.

Glowing hot gases are very beautiful. So are the incandescent embers.

campfire in the city

The oxidation that is taking place is the reaction of cellulose and oxygen. Cellulose is a polymer of glucose, a sugar molecule. As the wood burns the gases released include carbon dioxide, carbon monoxide, water vapor, and gaseous hydrocarbons.

From “How Stuff Works” : http://science.howstuffworks.com/environmental/earth/geophysics/fire1.htm

• Something heats the wood to a very high temperature. The heat can come from lots of different things — a match, focused light, friction, lightning, something else that is already burning…  
• When the wood reaches about 300 degrees Fahrenheit (150 degrees Celsius), the heat decomposes some of the cellulose material that makes up the wood.  
• Some of the decomposed material is released as volatile gases. We know these gases as smoke. Smoke is compounds of hydrogen, carbon and oxygen. The rest of the material forms char, which is nearly pure carbon, and ash, which is all of the unburnable minerals in the wood (calcium, potassium, and so on). The char is what you buy when you buy charcoal. Charcoal is wood that has been heated to remove nearly all of the volatile gases and leave behind the carbon. That is why a charcoal fire burns with no smoke. 

heat and light: two forms of energy

What I noticed the most was how lovely it was to sit around a fire and listen to conversation, watch the family roast marshmellows, and think how very lucky I am to be able to experience this wonderful phenomena.

Sulfur mining:

http://www.usmra.com/repository/category/mining/wallpaper/sulfur-source-aprw33-xl.jpg

more links about sulfur:

http://tinyurl.com/5rejntz
http://elitistreview.com/wp-content/uploads/2010/11/27/opus-number-1111-three-cheers-for-sulfur-in-wine/sulfurvent.jpg
http://jackandjilltravel.com/wp-content/uploads/2011/04/DSCN3657-1.jpg

http://www.h2so4today.com/resources/pdf/FallWinter2010.pdf

So after looking at all these links, what color is sulfur?

ans: yellow

One of my Chem 201 students sent me this link -

http://www.nytimes.com/2011/09/28/business/energy-environment/simbol-materials-plans-to-extract-lithium-from-geothermal-plants.html?_r=2&ref=todayspaper

and I am very excited for two reasons:

First, the student who sent the link was very pleased to be able to understand a bit about this article and that made me very happy.

Second, this is such an interesting topic – follow the lithium and look for some amazing changes in our society…

Please read it if you have a minute.

I’m trying out some new software for making lecture presentations into videos. I’ve posted my first attempt:

http://justonly.com/chemistry/videos/limiting_reactant/limiting_reactant.html

In this video I work through a problem. It isn’t perfect – for some reason the image zooms and I’m not sure why – but it might be a way to have some explanations of the more difficult homework problems posted on the Internet. Let me know what you think about this.

While I am one of the first people to say how much I dislike cell phones in the classroom – ringing, singing and beeping at the wrong moment, calling my students like a siren out into the hallways and disrupting class – here is one student who has found an excellent use for her cell phone camera – she is documenting events in the laboratory.