Moles

                           

 This past week in my chemistry class we have been going over moles and how to use it. A mole is a unit of measurement that shows the amount of something. For example, 1 mole of carbon-12 has a mass of 12g. This is also the molar mass. The molar mass is the mass of 1 mol of a substance. To find the molar mass of an element we find the mass number of the element on the periodic table. To find the molar mass in a chemical formula one needs to find the formula weight. The formula weight will be the same number as the molar mass. The only difference is that formula weight is in amu while molar mass is in grams. Here is a link of an example of how to calculate the formula weight http://chemistry.about.com/od/workedchemistryproblems/a/Molecular-Formula-Simplest-Formula-Example-Problem-1.htm .

 Moles also provide a bridge from the molecular scale to the real-world. To do this one must know Avogadro's number. Avogadro's number is 6.02 x 10^23. The diagram to the right shows how to use moles. Some of the mole relationships are  that 1 mole of atoms, ions, or molecules contains Avogadro's number in those particles and 1 mole of molecules or formula units contains Avogadro's number times the number of atoms or ions of each element in the compound. To understand more about moles and to figure them out here is a link to a  website http://misterguch.brinkster.net/molecalculations.html.

The Poisoner's HandBook By Deborah Blum
     For my literacy glog I chose to read The Poisoner's HandBook.  I chose  this book because it is about how forensic science started in the roaring twenties. What caught my interest in reading it, was how many poisons were not able to be detected through forensic evidence and how forensic science has changed over time. So far on what I have read, I have found out that many murders were every hard to investigate because many of the poisons were hard to find in a human body. According to the book on page 10 for example the poison chloroform, a person could take one-third of an ounce, and would die within minutes. An autopsy in the book stated ""Therefore we can establish nothing by exhuming the bodies. Mors may have given each of his victims a quart of chloroform but we couldn't prove it by an autopsy."" pg13. When I read this sentence I was fascinated on how much has changed over time. In autopsy then, one was not able to determine poisons in a body, but now with new technology one is able to determine in an autopsy how much of a poison is the body and what type of poison was consumed by the person.

The Ultimate Change

This past week, my chemistry class has been going over significant figures. Through all the stress, I was finally able to understand the importance of it.  So why are significant figures so important?

 

Well for one, significant figures help to get a better accuracy in measurements . For example, one can be trying to install tile into a house. Say that the dimensions of the room are 10ft x 4ft or are they  really 10.35ft x 4.81ft. By saying the dimensions with more accuracy, this can help the person  figure out how much tile will be needed for the room. If one did not now the other .35ft x .81ft, then how will one know how much tile needs to be cut in order to place closer to the wall.  Another example is that significant figures can change a theory  and make a discovery just like in the blog called Neutrino Physics. Yes, knowing significant figures can help one save money on buying tile, but making a discovery by using significant figures is really impressive!

Silk and the Samurai's Sword

Silk and the Samurai's Sword might be different from each other, but they  have something in common. They both  have gone through a chemical change. Silk is a modern day wonder while the Samurai Sword has been used for centuries.

The chemical change that silk has gone through is water turning into a  protein fiber. This happens when the silk solution sets at room temperature and letting the protein fibers assemble by themselves. Next the solution is boiled, then the protein fibers are detach while the water is evaporating. This process makes silk. The silk can now be used for various things, for example to create gears, bolts and senors. Silk is also biocompatible. This means that it can be implanted into the body with no harm done to the living tissue.  

The chemical change that the Samurai's Sword has gone through is the mixing of iron and charcoal to create steel. This happens when iron and charcoal are heated together in a tatara for 3 nights and days. After the steel has been heated it is separated into two groups, high carbon and low carbon. The high carbon is used for the razor shape edge of the sword, while the low carbon is tough and allows for shock absorption. A blacksmith will then shape the high carbon steel so that the low carbon may be able to fit in the high carbon steel. This allows for the perfect balance of properties which is the samurai's most durable and prized weapon (taken from http://www.pbs.org/wgbh/nova/tech/crafting-samurai-sword.html, 1/26/12). To make the distinctive curve on the sword, the sword is then heated again to 1,500 degrees Fahrenheit . After that the sword is placed into a shallow container of water to cool. The speed of the contraction in the water between the low and high carbon causes it to bend. Thus creating the Samurai's Sword

sources

http://www.pbs.org/wgbh/nova/tech/crafting-samurai-sword.html, 1/26/12

http://virtualgardnerblogs.weebly.com/chemistry.html, 1/26/12

me

I am very passionate about everyting having to be perfect. If it is not perfect, I get mad at my self for it not being perfect. Then I have to do it again untill I think it is perfect. I don't know why everything has to perfect. I just like it like that.