Demarco,+Alexis

8-27-09 The graphics are showing how and what matter is broken down into. In figure 1 the graphic shows that if the matter is uniform then it’s a fixed composition and if its fixed composition its chemically decomposable, therefore the matter is either an element or a compound. However, if not uniform then its is a heterogeneous mixture. And if its not a fixed composition then the matter is a solution. Figure 2 and 3 are very similar though. It shows that matter can be broken down into either mixtures or pure substances. If it is a mixture then it’s either heterogeneous or homogeneous. And if it’s a pure substance it is then a compound or an element. Except in figure 3 it gives examples of heterogeneous, homogeneous, compounds, and elements. My favorite graphic explaining how matter is broken down is figure 2 because it’s simple and easier to understand.

Alexis, Your response to the class of matter post was really short. :( MW

8-28-09 I learned the difference between distillation and filtration. They are both used to separate mixtures. Since mixtures usually have a variety of matter that create the mixture. And to find out what all is in the mixture you must either use filtration or distillation. I never knew that there was two different types of chromatography used to separate mixtures. I think this information is very relevant to this class because we will be doing experiments on separating mixtures in this class and we will need to know what type of chromatography needs to be used.

8-31-09 Measurement is very important when working with anything that requires combining items or determining the weight, length, or volume of an object. With my personal experience I sometimes cook so I must know how to accurately measure the ingredients so the recipe does not get messed up. I should be able to know both systems of measurment for me to be able to get the correct amount of inredients into the recipie. Also I am a diver so i need to be able to know the measurment of the board. I need to know this because when I go to do a dive i must know how long the board is so my approach to the dive will be correct and not mess up my dive.

Alexis, I know there are different heights for the diving boards. 1 meter, 3 meter and 5 meter come to mind. Good post! MW

9-7-09 From reading this article i have learned a lot about measurement. Before this class i have only ever heard of a few of the 7 basic units of system of units measurements. The 7 basic units are the meter, kilogram, second, ampere, kelvin, mole, and the candela. All of these are different kinds of measurement used to measure a variety of different things. I also learned that there are original's of each of these. They are the exact length, weight, etc. of these different units. They are kept locked away in a safe where no one can tamper or ruin it.

9-14-09 Airline Security From this article I learned that airline security is a lot more difficult then what i thought. The people must look and make sure there are no explosives or items of danger going into the airport. The x-ray machines are alot more complex then i ever imagined. I never really thought about how they worked before, but most bombs are built by using household items that can be found in drugstores pretty much anywhere. People who created the screeners are trying to improve them to make it easier to detect the dangerous chemicals used to create the bombs. X-ray computed tomography serves as a cornerstone of security screening in the airports around thw world.

10-7-09 Mole Day The mole is a basic unit of measurmant in chemistry. The mole is based off of Avogadro's Number which is (6.02 x 10^23). For any given molecule one mole is the mass whose number is equal to the atomic mass of the molecule. Amadeo Avogado was an Italian scientist who was one of the founders of physical chemistry. He is also well known for his hypothesis called Avogado's Law, at a fixed temperature and pressure, equal volumes of gases contain the same number of molecules. The number was named after him in recognition of him being the first person to argue in favor of the existence of atoms. Avogado's number is used around the world by most scientists today. It makes it easier for chemists to measure the mass of a very small molecule that you wouldn't be able to measure most molecules without it.

Lexi, Good scientific references on your post! MW

Dust Explosion and Stoichiometry From that article i never knew that dust could cause an explosion, let alone cause deaths. It also shocked me how the rapid fire can travel through a plant from the ignition of combustible dust. And just from a single spark the dust can ignite and the explosion will travel through plants. This is quite a reaction that could occur because of something as simple as dust. This relates to stoichiometry because a certain amount of dust in the air is needed for the explosion to occur and the amount of dust can amount to how large the explosion is and the consequences from it.

Lexi,

Well done. I think you captured the essence of the article. MW

12-3-09 Sulfur Hexaflouride This article was very interesting to me considering that helium and sulfur hexaflouride are pretty much completely opposite gases. Helium when breathed in makes your voice high and sulfur hexaflouride does the complete opposite and makes your voice very low. What also interests me is that i never really understood the concept of how balloons would deflate. With a helium balloon the gas molecules will leak out causing the balloon to deflate. However, on the other hand with a balloon filled with sulfur hexaflouride the balloon overtime will expand, this happens because air molecules leak into the balloon easier than the sulfur hexaflouride molecules are able to leak out. Another thing that i find interesting from this article is that I thought that sulfur hexaflouride gas would be pretty dangerous, however since the two gases are combined, the gas is similar to any of the noble gases.

Lexi, Good post! MW

12-18-09 Motion Detectors This article became very interesting to me because I never had a clue about how motion detectors work but I wondered how they were able to sense a person coming. One in particular fascinated me was the motion detector that can sense motion by warmth of the human by using infrared radiation. And when someone is coming it can sense the warmth of that person and the lights will turn on. I would think that motion detectors would be using some sort of a light frequency but it really uses the particles of light instead. I never really thought that chemistry had anything to do with lights or motion detectors, but this article showed me that chemistry is part of our everyday lives.

Lexi, Yes chemistry is all around us.:) MW