Tag Archives: Chemistry

Wait, A New Element?

So while I was reading the news, I happened to discover a page titled ‘Existence of New Element Confirmed’. That got me to wonder, was there really a new element discovered? It turns out, researches at Lund University has confirmed that a new element with the atomic number 115 exists, temporarily named Ununpentium (Uup abbreviation). Currently, the name is being debated by the International Union of Pure Applied Chemistry (IUPAC). The research verified findings of the same element during a prior experiment performed in 2004 led by a Russian research team (“Existence of New Element“, 2013). Both research teams performed the same experiment; calcium-48 ions were bombarded at a thin film of americium-243. The collision of the ions and atoms resulted in a formation unupentium, which decayed milliseconds later due to its radioactive nature (“Ununpentium“, n.d.). Although this begs the question “how was this element confirmed to exist”, analysis of  the energy released through radiation matched the theoretical values of the element confirming its existence (“Existence of New Element“, 2013).

Ununpentium Bohr Model
Ununpentium Bohr Model

That got me to ponder, what chemical/physical properties does this new element have? Unfortunately, it is currently impossible to give a definitive answer to that. Every isotope of Uup that has been discovered all have an average half-life of 100ms. That means a large enough sample cannot be collected to observe the element’s properties. However, it is predicted that the element has similar properties to that of the group 5 elements on the periodic table (“Ununpentium“, n.d.). Uup is classified as a synthetic element, elements which have a half-lives so short relative to the Earth’s age, that most or all naturally occurring elements would have decayed completely (“Synthetic Element“, n.d.). The majority of them lie within period 7 of the periodic table.

Synthetic Elements
Synthetic Elements

So why discover new elements if they decay so quickly? Not the most moral or conventional example but plutonium, an element discovered in 1941 and was used in the atomic bomb dropped on Nagasaki (“Plutonium“, 2012). Since most of the synthetic elements are all radioactive, the majority of the are used for nuclear weapons. On a more accepted aspect of usage, plutonium is used in nuclear reactors to provide electrical energy for cities around the world (“Nuclear Reactors“, 2013). Atomic energy is considered clean as it doesn’t produce air pollutants through usage and can be used as an alternative to fossil fuel burning. However, disasters such as the recent Fukushima earthquake in 2011 and the Chernobyl meltdown in 1986 serves as a constant reminder and strong argument against atomic energy.

I want to highlight the importance of the scientific method here. The original research experiment performed in 2004 produced quantifiable results. At the time, technology could not confirm such results found. The important thing was the experiment set up was reproducible in another lab. With more advanced technology and further research into the theoretical data was the reason why the team at Lund University could confirm results. Without a reproducible experiment, a scientific claim cannot be verified.

Works Cited

“Existence of New Element Confirmed.” ScienceDaily. Lund University, 27 Aug. 2013. Web. 28 Aug. 2013. <http://www.sciencedaily.com/releases/2013/08/130827091636.htm>.

“Nuclear Reactors.” World Nuclear Association. N.p., July. 2013. Web. 28 Aug. 2013. <http://world-nuclear.org/info/Nuclear-Fuel-Cycle/Power-Reactors/Nuclear-Power-Reactors/#.Uh3uPxsSZVV>.

“Plutonium.” US Environmental Protection Agency. N.p., 6 March. 2012. Web. 28 Aug. 2013. <http://www.epa.gov/radiation/radionuclides/plutonium.html>.

“Synthetic Element.” Princeton University. N.p., n.d. Web. 28 Aug. 2013. <http://www.princeton.edu/~achaney/tmve/wiki100k/docs/Synthetic_element.html>.

“Ununpentium.” Wikipedia. N.p., n.d. Web. 28 Aug. 2013. <http://en.wikipedia.org/wiki/Ununpentium>.

The ‘Plaster of Paris’ Explored

Over the Chinese New Year break, I had to opportunity to relive one of my favorite art experiences from middle school, carving plaster, more specifically Plaster of Paris or Gypsum. (Chemistry Daily, 2007) After day four of carving I became acutely aware of the physical properties of Gypsum, its softness and hygroscopic qualities (ability to take moisture out of the air) to name a few and began to wonder what made the substance that way. Gypsum, formally known as calcium sulfate dihydrate (CaSO4.2H­­20) is a mineral, which is chemically defined as being a “naturally occurring inorganic element or compound having [homogenous crystalline structure, chemical composition], and physical properties.” (Kentucky Geological Survey, 2005)

The calcium sulfate dihydrate is comprised of sheets of intramolecular ionic bonded Ca2+ and So42- ions held together by the intermolecular hydrogen bonding of water. The dihydrate means that for every molecule of calcium sulfate there are two molecules of water attached to the sulfate ion with coordinate covalent bonds. (Kauffman, 2013) Due to the weak intermolecular hydrogen bonding, calcium sulfate dihydrate is quite soft, as these bonds being easily broken, a physical property I am very thankful for. Now for most commercial applications, Gypsum is typically sold and kept as a grind up power, that has been calcined, or had its moisture removed with intense heat, as calcium sulfate hemihydrate (one water molecule for every two calcium sulfate molecules).(Lafarge Prestia , 2000) The reaction is shown by:

CaSO4.2H2O + Heat → CaSO4.0.5H2O + 1.5H2O

Depending on at what pressure this reaction occurs at, a product with different physical properties is formed. Alpha plaster is formed when calcium sulfate dihydrate is calcined at about 150 degrees Celsius in an autoclave (a heated, pressurized container for chemical reactions) at higher than atmospheric pressures. Beta plaster on the other hand is calcinated at atmospheric pressure. (Lafarge Prestia , 2000) Manufactures do this to control the shape and size of crystal growth in the plaster, with alpha plaster having larger crystals, a higher mechanical strength, and low porosity while beta plaster has smaller crystals, lower mechanical strength, and higher porosity. (National Research Development Corporation) This reaction can be taken further to the point where calcium sulfate becomes an anhydride (compound with water removed) and all of the water of crystallization evaporated. In this form there are no polar water molecules to interfere with the ionic lattice formed by electrostatic attractions of Ca2+ and So42- ions, so it’s hardness increases dramatically. (Chemistry Daily, 2007) However this reaction is actually reversible, with the anhydride or hemihydrate form reverting back in an exothermic reaction to the dihydrate form if introduced to enough water. I had found the reaction that I crudely did to create the plaster for my sculpture, which was using beta plaster.

CaSO4.0.5H2O + 1.5H2O → CaSO4.2H2O + Heat

It turns out this material I used for an art project has roots stretching back 9000 years to the Anatolia region. Throughout history Gypsum has had various applications, from being used in Egyptian monuments to modern day drywall, with most stemming out of the field of construction. (Lafarge Prestia , 2000) There are some of the historical uses, where due to its ability to protect internal structures from fire it was used to cover the exteriors of houses. More specific and diversified uses for calcium sulfate have developed over time, some requiring particular physical attributes like “setting times, fluidity, viscosity, their hardening kinetics, their permeability (through pore [size]), their mechanical strengths, [and] their resistance to abrasion.” These conditions are met through a combination of alpha plasters, beta plasters, and neutral fillers. (Lafarge Prestia , 2000)

Calcium sulfate’s uncanny ubiquity in modern life, from the molds used to fashion ceramic molds or dentures, to the internal walls and ceilings in most buildings, to the decorative art on the outside of the building, to its discovery on mars (Webster & Cole, 2011) all remind me of how much a single substance can impact the direction of human society and culture. Additional uses for calcium sulfate include agricultural applications to increase the water penetration and aeration of sour (lime lacking) soil but run the risk of excess sulfate tainting the groundwater. Also just recently medical applications for calcium sulfate, acting as a bone void filler to be introduced slowly into the body at the same rate as new bone growth, have been posited. (Tangri, Prasad, Suri & Agrawal, 2004) All these from a single mineral, but while considering its uses one must also ponder the process it takes to produce. The arduous industrial process involved with mining, classifying, processing, and distributing this one mineral puts into perspective how much of the production line we as consumers are not typically aware of. (Lafarge Prestia , 2000) However based on the recent applications of this substance, calcium sulfate will be continued to be an integral but underemphasized part of people’s lives.

References:

Chemistry Daily. (2007, January 04). Plaster. Retrieved from http://www.chemistrydaily.com/chemistry/Plaster_of_paris

hydrate. (2013). In Encyclopædia Britannica. Retrieved from http://www.britannica.com/EBchecked/topic/278148/hydrate

Kentucky Geological Survey. (2005, December 12). Many definitions of minerals. Retrieved from http://www.uky.edu/KGS/rocksmn/definition.htm

Lafarge Prestia (2000, December 11). Caso4?,h20. Retrieved from http://www.lafargeprestia.com/caso4___h2o.html

National Research Development Corporation. National Research Development Corporation, (n.d.). High strength plaster of paris – alpha plaster. Retrieved from website: http://www.nrdcindia.com/pages/highplas.htm

Tangri, R. P., Prasad, R., Suri, A. K., & Agrawal, P. R. Bhabha Atomic Research Centre, Materials Processing Division. (2004). α-calcium sulphate hemihydrate as bone substitute. Retrieved from website: http://www.barc.gov.in/publications/nl/2004/200406-2.pdf

Webster, G., & Cole, S. (2011, December 07). Nasa mars rover finds mineral vein deposited by water. Retrieved from http://marsrover.nasa.gov/newsroom/pressreleases/20111207a.html

Images Cited:

Guidechem. (Producer). (2010). Calcium sulfate dihydrate. [Web Photo]. Retrieved from http://www.guidechem.com/products/10101-41-4.html

Lafarge Prestia (Producer). (2000). Plaster manufacture. [Web Photo]. Retrieved from http://www.lafargeprestia.com/caso4___h2o.html

Smith, S. E. (Photographer). (2003). Calcium sulfate dihydrate. [Web Photo]. Retrieved from http://www.wisegeek.com/what-is-calcium-sulfate.htm

The Hole in Our Ozone

Remember back in 2006 when there was a big panic about the news of a hole in our ozone? However as time past, the talks about this hole gradually died down. Recently I came across a news article that states, “Some scientists believe the ozone layer, protecting earth from the sun’s ultraviolet radiation, could be recovering.” (Valente, 2012). At the moment since Earth is the only known home for human beings, it is important for us to understand and protect the environment we call home for our future generations. Therefore I decided to do some further research and reading into our Earth’s Ozone layer.

For those of you who don’t know what the Ozone is, here is a brief summary. The Ozone layer is a thin layer of gas that naturally occurring in the Earth’s stratosphere, an area roughly 20-50km above the Earth’s surface. (Figure 1) This layer of ozone protects us from the harmful UV radiation from the sun. (Wilson, 2013) UV radiation has high energy and a short wavelength therefore it can penetrate the skin, manipulating DNA, which in result can cause cancer and other skin disorders. (Office of Air and Radiation, 2010).

The location of the Stratosphere
The location of the Stratosphere (Figure 1)

What exactly is the Ozone layer made of? How does it prevent the penetration of UV radiation? The ozone is composed of the 3 different allotropes of oxygen, O, O2, and O3. These atoms and molecules undergo the Ozone Oxygen Cycle, where the molecules are broken down into atoms and atoms rejoin to make molecules. (Wilson, 2013). Here are some photographical representations of this process:

Under UV light, O2(g) ---> 2 O(g)
Under UV light, O2(g) ---> 2 O(g)
O(g) + O2(g) ---> O3(g)
O(g) + O2(g) ---> O3(g)

Both processes are exothermic. The light energy from UV light is transferred in to thermal energy or heat therefore being absorbed, preventing it from reaching the Earth’s surface. (NASA, 2008)

The Ozone hole is found above Antarctica and covers averagely around 17.9 million square kilometers. (Welch, 2012). (Figure 2)The hole is not a physical or literal hole but an area where there is severe depletion of Ozone. As National Geographic states, “Chlorofluorocarbons (CFC) used by industrialized nations for much of the past 50 years, are the primary culprits in ozone layer breakdown.” Because CFC’s are quite nonreactive as they are they are nontoxic, noncorrosive, nonflammable, and very stable. They were found in fire extinguishers, as propellants in aerosols, solvents in electronics manufacture, coolants for refrigerators and air conditioners and as foaming agents in plastics.

Biggest measured hole, Sept 22 2012, 21.2 million square kilometers
Biggest measured hole, Sept 22 2012, 21.2 million square kilometers

CFC’s easily rise to the stratospheric level on earth. In Antarctica, especially during the cold winter nights where there is no sunlight, a polar vortex, strong circular winds, isolates the air in the polar region that traps the CFC in the stratosphere.  (Carver, 1998) When the sun finally comes out again, and the UV light hits the clouds of CFC’s it breaks it down into atoms of chlorine and bromine. These acts as catalyst in the destruction of ozone

O3—>O2 + O

Cl + O3—>ClO + O2

ClO + O—>Cl + O2

According to the U.S. Environmental Protection Agency, One chlorine atom can break apart 100,000 ozone molecules, and bromine is 40 times more destructive. These atoms destroy much of the ozone over Antarctica, by causing an imbalance of ozone to the natural cycle. (Wilson, 2013). Luckily as of 2000, the Montreal protocol demands the removal of CFC in production of products. However even after regulations have been put into place for the ban of these harmful chemicals, the hole hasn’t had significant improvements. Paul Newman, a chemist from NASA predicts, “the ozone layer above Antarctica likely will not return to its early 1980s state until about 2060.”(LiveScience, 2012)

Bibliography:

LiveScience. (2012, Oct 25). Antarctic Ozone Hole Is The Second Smallest Since It’s Been 20 Years. Huffington Post. Retrieved from: http://www.huffingtonpost.com/2012/10/25/antarctic-ozone-hole-size-2012_n_2016713.html

Valente, M. (2012, Nov 24). Hopes grow on shrinking ozone hole. Aljazeera. Retrieved from: http://www.aljazeera.com/indepth/features/2012/11/20121124142740268174.html

Welch, C. (2012). The Ozone Hole (weblog). Retrieved from:http://www.theozonehole.com/2012ozonehole.htm

Wilson, T.V. (2013). Can We plug the hole in the ozone layer? HowStuffWorks. Retrieved from: http://science.howstuffworks.com/environmental/green-science/question778.htm

National Geographic. (n.d.). Ozone Depletion. National Geographic:Environment. Retrieved from: http://environment.nationalgeographic.com/environment/global-warming/ozone-depletion-overview/

Carver, G. (1998). Part III. Science of the Ozone Hole. University of Cambridge Centre for Atmospheric Science. Retrieved from: www.atm.ch.cam.ac.uk/tour/part3.html

Office of Air and Radiation. (2010, June). UV Radiation. U.S Environmental Protection Agency. Retrieved from: http://www.epa.gov/sunwise/doc/uvradiation.html

University of Wisconsin. (2008, Sept. Chemical of the Week: Ozone. Retrieved from: http://scifun.chem.wisc.edu/chemweek/ozone/ozone.html

National Weather Service. (2007). Layers of the Atmosphere. National Oceanic and Atmospheric Administration. Retrieved from: http://www.srh.noaa.gov/srh/jetstream/atmos/layers.htm

Transistors or Semiconductors? The Cells of Electronics

When I first began building my computer, I learned that most computer parts only require about three different voltages, but wall sockets in the US produce 110 volts and other countries use 220 volts. That got me wondering, wouldn’t the 110 volts travel all throughout the computer? How do computer parts reduce the voltage? After getting my computer running, I researched my question for the answer: transistors. It didn’t really gave me a full understanding of how, so I decided to do more research.

If cells are the building blocks of life, transistors are the building blocks of the digital revolution. Without transistors, the technological wonders you use every day — cell phones, computers, cars — would be vastly different, if they existed at all.

Nathan Chandler at HowStuffWorks, (Chandler, n.d., p. 1)

So the guys at HowStuffWorks gave a brief overview of how transistors work. Transistors are somewhat like water faucets. In addition to starting and stopping the current, they can control how strong the current is, allowing the resulting voltage to be bigger or smaller than the original. All this is thanks a series of semiconductors, once made out of germanium is now mostly produced with silicon. Semiconductors are materials that can conduct electricity, but not very well. Naturally, Si and Ge are very weak semiconductors, conducting almost no electricity at all, but through a process called doping, the conductive properties can be changed.

Transistors from Wikipedia
Transistors from Wikipedia

Doping is the process of adding small amounts of impurities into, in this case, silicon or germanium crystal lattice. Both Ge and Si have 4 valence, the impurities usually come from either group 3 or group 5 elements, depending on the type of semiconductor desired. Having 3 valence electrons, elements such as boron and aluminum can be added to Si, creating a substance where the added impurity is missing an electron. This is called a P-type due to its positive charge from the missing electrons. Conversely, phosphorus or arsenic, elements with 5 valence electrons can be added to create N-type semiconductors due to its additional electrons giving a negative charge. A nice diagram is can be seen here in Hyperphysics.

Now equipped with both types of semiconductors, you can create a transistor by placing a series of either P-N-P or N-P-N. When applying an electrical current in the middle, “electrons will move from the N-type side to the P-type side.” Depending on the initial strength of the current and how impure the semiconductors are, the transistor will either amplify or decrease the current.

All this got me thinking on another question of mine. What other uses are there for semiconductors? The simplest use of semiconductors is diode. A diode consists of one P-type and N-type semiconductors. When put together, an electrical current can flow through from the P-type region to N-type region, but not the other way. This is because electrons can only flow from positive to negative, but not the other way around, as the N-type region will repel the moving electrons.

These can be made into Light Emitting Diodes, or LED’s, that emit a multitude of colors. Multiple semiconductors can be combined to create Random Access Memory (RAM) to increase your computer’s speed or Microprocessors for calculators and other electronic devices.

Light Emitting Diodes
Light Emitting Diodes

So to put it in perspective, just as cells build living things, transistors, according to Nathan Chandler, are the building blocks of all electronics. But seeing as semiconductors build transistors, I believe that these special compounds are the true cells in electronics. Although semiconductors have existed in electronics for quite some time, new uses and circuitry of electronics is being discovered every day.

Bibliography

Chandler, Nathan. “HowStuffWorks “How Transistors Work”.” HowStuffWorks. N.p., n.d. Web. 13 Jan. 2013. <http://electronics.howstuffworks.com/transistor.htm>.

Semiconductor Device.Wikipedia. N.p., n.d. Web. 13 Jan. 2013. <http://en.wikipedia.org/wiki/Semiconductor_device>.

The Doping of Semiconductors.Hyperphysics., n.d. Web. 13 Jan. 2013. <hyperphysics.phy-astr.gsu.edu/hbase/solids/dope.html>.

Snap, crackle, pop? Not really

“Note: buy a new alarm” thinks Bill, late for his potential million-dollar meeting. It’s 9:30 in the morning, and Bill is frantically searching for the slightest loops in traffic to weave through. The green light is flashing; he’s not about to miss it. Pressing harder on the accelerator, Bill speeds up to gun it. 10mph, 20mph, 30…it seems he’s able to make it. Out of the corner of his eyes, a motorcyclist speeds onto his path of direction with possibly double Bill’s speed. Bill hit the brakes, but it was too late. The motorcycle hit directly into Bill’s car, the motorcyclist was thrown forward into busy traffic. Bill hurriedly got out of the car, running to the man expect a motion-less body on the ground. Instead, the man was standing and walking towards his motorcycle. How is he walking? Why isn’t he in the intensive care unit with a few cuts and broken bones?

Bill’s thinking clearly underestimated the strength of the bone. The bone is one of the strongest materials found in nature, capable of withstanding at least 19,000 pounds per one cubic inch. To give you an image, imagine taking an ice cube out of your freezer, and stacking five pickup trucks onto the ice cube. The ice cube is how big the cubic inch of bone would be, and the five pickup trucks would be how heavy 19,000 pounds are, approximately. It’s also about four times the strength of reinforced concrete. In fact, bone has a strength to weight ratio superior to any other natural material on earth.

Bet youre feeling pretty strong now.
Bet you're feeling pretty strong now.

The bone’s strength comes from its bone tissues, which has two parts. The first is a hard outer layer of bone, composed of compact bone tissue with minimal gaps and spaces in the tissue. This is the heavier part of the bone, as it factors around 80% of the bone’s weight. It is created by making a matrix, and contains a strong ionic bond between calcium and phosphorus as well. The interior of the bone is called the trabecular bone tissue. It is a matrix of hollow cells, walls as thin as paper. This part of the bone, whilst only giving 20% of the bone’s weight, has nearly ten times the surface area of the compact part of the bone. It is this part of the bone that bends, and allow for bone to be light and flexible, yet sturdy and strong.

Running increases the body mass by three times, jumping by ten. How, then, is the bone able to take this much pressure everyday without wearing out so quickly? The answer lies in the cells and the cycle that provide the maintain the body’s bones. There are three types of cells to maintain the bones:

  • Osteoblast – the cell that lays down new bones when needed, and taking minerals from extracellular fluids and creating new bone matrices.
  • Osteoclast – resorb bones by releasing acids and enzymes
  • Osteocyte – communicate to the cells about pressure and stress from inside the bone cell, and also destroy the bone through a rapid mechanism. These were originally osteoblasts that were trapped in the matrices they created.

These three cells are vital to bone regulation. As the bone is resorbed, osteoclast releases a signal (cytokines) which encourages osteoblasts to lay new bones. As the osteoblasts lay new bones, it adds small proteins into the bone structure they create. Osteoclasts come again, and both osteoclasts and osteocytes break down the bone matrices. When the bone is resorbed, these proteins are released and act as signals for osteoblasts to come and lay new bones once again. This vicious cycle of breaking down and making new bones are essential for both maintaining the bone and preventing the bone structure from going haywire. Another reason for this cycle is so the body can adapt under different stresses and under different circumstances. It is estimated that every seven years, all the old cells in your bone is replaced with new cells, and the entire of the skeletal mass may be replaced every 10 to 25 years. Indeed, it’s fascinating that the bone does this to keep our skeletal structure. So drink your milk, kids.

The cycle of bone turnover
The cycle of bone turnover

Works Cited:

Bones and Joints.” Health Lessons Online. N.p., n.d. Web. 20 Oct. 2010.

Clarkson, Paul. “The Science Creative Quarterly » DEM BONES, DEM IMPORTANT BONES.The Science Creative Quarterly. N.p., n.d. Web. 20 Oct. 2010.

Hall, Susan J. Basic Biomechanics with Online Learning Center Passcode Bind-in Card. 5 ed. New York City: McGraw-Hill Humanities/Social Sciences/Languages, 2006. Print.

Lamb, Robert. “Discovery Health “How do broken bones heal?“.” Discovery Health “Health Guides”. N.p., n.d. Web. 20 Oct. 2010.

Hydrophobia

Wouldn’t life be much easier if you didn’t have to spend time drying yourself off after a shower or a dip in the pool?  Well, certain molecules have that luxury.  Such molecules are known as hydrophobic molecules.  Hydrophobic molecules are molecules that are repelled by water.  This happens because water is polarized and forms hydrogen bonds with itself and since hydrophobic molecules are non polar they are unable to form new bonds with water.  Instead, the two repel one another.

But where it really gets interesting is when a substance is super hydrophobic.  Super hydrophobicy is achieved with very rough surfaces that can suspend small liquid drops.  A rough surface is necessary because when water is put on that surface it can’t fit into the very narrow channels due to the rough surface and the substance’s hydrophobic nature.  In turn, this causes the water to roll off the substance.

In another instance, even when a rough hydrophobic substance is submerged in water it comes out clean due to its hydrophobic properties, but that’s not all.  In fact, the microscopic bumps in the surface trap air in between them, creating this thin film of air separating the substance from the water. 

Interestingly, this effect has been used for millennia as a self-cleaning tool in plants.  The super hydrophobic nature of plants reduces the adhesive force on water droplets allowing water molecules to expend more energy forming spheres due to water’s self attraction.  Now, dirt particles on the leaf on a plant naturally adhere to these spheres which then roll off the leaf due to gravity; and presto chango the leaf is clean.  Furthermore, the fact the water doesn’t stick to the leaf prevents bacteria and fungi from growing on the plant as there is no water for the fungi or bacteria to grow. 

More recently, this concept has been applied to other areas, like solar panels for one.  Solar panels lose efficiency when covered with just about anything including dust, but by having a super hydrophobic coating applied to the solar panel this problem is averted in the same that plants clean themselves.  Moreover, having a wet solar panel would be problematic as algae would likely begin to grow.  Luckily, by keeping the panels dry through properties of super hydrophobic molecules the potential for algae growing is eliminated.   

Evidently, nature’s properties and adaptations have been twisted and morphed into more modern inventions and it’s interesting to see how influential nature is and how effective.

Kekule’s Dream

Sometimes to make a scientific breakthrough no matter how well tested the idea you need to be able to think creatively.  For German Chemist Friedrich August Kekulé (1829- 1896), the inspiration for his out of the box thinking came from a dreamlike vision.  Up until 1858 chemists did not really have a clear understanding of the structure of organic molecules but it was generally accepted that they formed ordered straight chains.

Kekule, a theoretical chemist was particularly curious as to why benzene had chemical properties that could not be explained using current theories. What was lacking was a clear understanding of benzene’s structure and finding the explanations he was looking for seemed impossible. However, one day while traveling home on the bus from his laboratory he dozed off and in his dream saw the straight chained benzene molecules twisting and turning in a snake like motion. One of the snakes caught hold of its tail and made a ring like formation.  When Kekulé woke he had a flash of inspiration and as soon as he got home made sketches of this dream form of benzene.

In 1865 Kekule presented a paper to the Royal Academy of Belgium proposing that the structure of benzene was a single hexagonal ring of six carbon atoms with alternating single and double carbon-carbon bonds. His theory met widespread approval from fellow chemists.

However his structure did not stand the test of time.  It wasn’t long before  a modern experimental procedure called x-ray diffraction revealed that the carbon-carbon bonds  in benzene were actually equal in length. Further experiments  supported the idea that Kekule’s alternating single and double bonds were not possible.  As a result his structure was replaced by a truer ‘resonance hybrid’ structure with the same arrangement of atoms but the length of each C-C bond being somewhere in between a single and double bond due to delocalised pi electrons.

Kekule’s story shows that being able to make creative connections between seemingly unrelated phenomena (a benzene molecule and a snake) can lead to significant advances in what scientists know.  They can’t rely solely on formal inductive and deductive reasoning as a way of knowing – they need to be able to think creatively as well.

Edward de Bono, regarded by many as a leading authority in the field of creative thinking said.

Logic is the tool that is used to dig a hole deeper and bigger, but if the hole is in the wrong place, then no amount of digging will get you to your intended destination.

So, the next time you are struggling to come up with your own creative lab idea allow yourself to dream a little.

White Phosphorus (WP)

Author’s Note (this is not part of the article): Those of you that take the time to look at the news in the past week, you may have noticed that tensions are rising again in the Gaza region. I first came to know of the issue during the 2006 Israel-Lebanon Conflict. I have since paid close attention to the crisis. You may find information on the recent development of the crisis on this website. Upon reading the linked article on this website, I began to do some research, which led to the creation of this post. I must warn you, however, I have very strong opinions on the delicate issue of Gaza, therefore, some degree of bias is present in this piece. It’s frustrating that this piece will never lead to peace.

What is suspected to be white phosphorus raining down upon Gaza.

White Phosphorus (also known as Willy Pete, you got to love the military types) is a type of munition used by the military for signaling, screening and incendiary purposes. It is used primarily to destroy enemy equipment and limit enemy vision. It can also be used for target location and navigation. More technical information can be found in this website.

White Phosphorus is a historically prominent chemical weapon. It was first formally used in World War I when British soldiers introduced this onto the battlefield in late 1916. Various evolutions of the original found their way into World War II where it was used greatly by the Allied and certain Axis Forces. White Phosphorous was also used in the Cold War Campaigns of Korea and Vietnam.

Chemically speaking, White phosphorus is an allotrope of the element phosphorus.

Allotropes are pure forms of the same element that differ in structure. For example, the element Carbon has several allotropes such as Graphite, Diamond, amorphous carbon and C60 fullerenes. Likewise, the element Phosphorus has many different allotropes such as White phosphorus, Red phosphorus, Violet phosphorus and many others. White phosphorus (also called tetraphosphorus) is a transparent, wax-like solid , which is known to turn yellow when in the presence of light. It is highly flammable and pyrophoric (or self-igniting) in air. To top it all, it is toxic (only 15 mg can be lethal upon ingestion). What better a chemical to use as a weapon.

Its reaction with the atmosphere is what makes it an able smokescreen. When white phosphorus burns in air, it forms phosphorus pentoxide:

P4 + 5 O2 → P4O10

Being hygroscopic (able to attract water molecules), phosphorus pentoxide absorbs moisture in the air to form liquid phosphoric acid:

P4O10 + 6 H2O → 4 H3PO4

This creates a mist of liquid droplets, which creates an effect similiar to that of a three-dimensional textured privacy glass. It scrambles visual light and infrared radiation. The blocking of infrared radiation makes infra-red optics and guided tracking systems useless making it a simple yet effective smoke screen.

However, we are not here to discuss the military merits of this white death. An issue brought up by the Human Rights Watch is in recent Israel-Gaza conflict there is suspected shelling using  white phosphorus shells by the Israeli side. This has caused much destruction of infrastructure, but that is beside the point. The point is that these shells have in used in the deliberate bombing of a civilian areas, including a crowded refugee camp. White phosphorus or what is suspected of being white phosphorus has resulted in several burn victims.

What is significant about white phosphorus fires is that they can’t be put out by traditional fire combating techniques. Chris Guiness, a UNWRA spokesman, states the following on preventing the fires:

What more stark symbolism do you need? You can’t put out white phosphorus with traditional methods such as fire extinguishers. You need sand, we don’t have sand.

More details on the specific shelling incident can be found in this Times Online Article. Another great consequence of the properties of  white phosphorus is the burns it inflicts upon those caught in the fire. White phosphorus burning can result in heavy 2nd-3rd degree burns. Phosphorus burns may also lead to multi-organ failure should it get into the system. Also, there is the toxicity of the smoke that comes with the fire. Similar to radiation, this, overtime, gains the potential to cause illness or even death. What is most frightening about white phosphorus is that it is not an efficient killer. It is much like the chlorine gas used in World War I (read cajo’s article for details) in that can kill in the most inhuman of ways. Perhaps it’s the cynicism that comes with my adolescent mind, however what I am personally most disgusted by the reaction of the Israeli forces. They have denied all allegations to the usage of this chemical and parellely cited that even if they did, they have not ratified any conventions acting against the usage of this.

Readers, I admit that I am inexperienced in the field of politics and my cynical nature does often distort my view of world. While I am informed of the reasons for why Israeli forces would target such areas for attack, what I am still concerned about is the fact that innocents would still be caught in the crossfire. Not only that, but attacks like these almost seem directed at the civilians and when politics finally brings the conflict to a close, I can only imagine that they will leave the place in ruins and open for new incidences of conflict. Readers, I ask you, is it an ethical decision to use this chemical for purposes such as this? Mind you, white phosphorus was never found with the intention of war, it’s just the minds of some people that brought it to this. This holds true for many other elements of warfare and opens a whole new arena for debate as to the ethical usage of chemical weapons. It also holds a frightening possibility. Soon, you may not even be able to trust the water that you drink. Is it possible that ‘enemies of the state’ have poisioned the water with some chemical or virus? 

So, in conclusion, I would like to question the direction military science is headed. Is it truly heading towards the reduction of casualties or preventing conflicts from dragging out? Does it hope for wars to drag out so that science can advance with the low humane standards of war as a catalyst? I don’t know the answers to these and it frustrates me that I can’t find them at the moment. So, I open the forum for replies in hopes that together we can better comprehend the situation and bring together our attained knowledge for solutions.

Desalination Salvation

Last class we were discussing what happens when you dissolve table salt, NaCl, in water, H2O. The intramolecular ionic bonds in the NaCl lattice are very strong and usually require a temperature of around 500 degrees Celsius to break. The fact that the ionic substance dissolves in the polar covalent substance, indicates that the attraction of the charges on the hydrogen and oxygen atoms of the polar covalent water molecules is greater than the electrostatic forces between the positively charged sodium ion and the negatively charged hydrogen atom. This means that the sodium and chlorine ions are surrounded by the negatively charged oxygen atoms and the positively charged hydrogen atoms, respectively. We then discussed what happens if all the water is evaporated, determining that once the water molecules are gone, the sodium and chlorine ions are once again attracted to one another and bond into their ionic lattice. This got me thinking, if it’s as easy as boiling some salty water to get the clean stuff, than why don’t all countries take advantage of this abundant resource to solve one of the world’s most pressing problems
I have since learned that it is not quite as simple…

To start I decided to learn more about methods of desalination. There are two primary types of desalination processes. The first is Reverse Osmosis and consists primarily of four steps.

Reverse Osmosis

The second is Multi-Stage Flash Distillation. This uses sudden changes in pressure to flash a portion of the water into steam. The water is then forced through remaining pressurized chambers, each time being introduced to a lower pressure, and flashing into steam. The steam is condensed on tubes of heat exchangers. In heat exchange the colder salt water enters the process and flows alongside the saline waste or distilled water that is already heated. The kinetic energy is therefore recycled and very little energy is lost. The combined effect of the pressure changes and the heat exchange methods make for one of the most efficient desalination processes.
Heat Exchanger
Although simple on paper, from my idea boiling the water and collecting the steam, came two very different and complex processes of desalination. As of now, the oceans as practical sources of water are just that: ideas. Though many regions have built, and use desalination plants, most notably the Middle East with 49.9% of the world’s desalinated output, the sheer amount of expensive energy needed makes most operations a dream. As well, cities far inland or highly elevated such as Mexico City, are unable to use this process, as it costs much more to transport and desalinate the brackish or sea water than it takes to transport clean drinking water. This is a blow to the benefits of desalination, as more often than not, these are the countries that need water the most.

Further hindering global use of desalination are the environmental concerns. As with most large plants, greenhouse gas emissions are a huge environmental risk. However, unique to the desalination plant, is the intake equipment. This has been described as “a giant vacuum” placed in the ocean, and is used to pull water into the plant. Death of marine organisms trapped in the grate is virtually guaranteed. One grate runs the risk of destroying the entire surrounding ecosystem. Another risk is the discharge of concentrated brine solution, a large plant could add as much as 1.5 billion litres of brine a day to the ocean.

The expensive and complex process, along with numerous pressing environmental concerns forces detailed consideration. Until there are more solutions than problems in desalination there remains no quick fix for the water question.

For further information on desalination see: http://www.fwr.org/desal.pdf, http://www.oas.org/usde/publications/Unit/oea59e/ch20.htm, http://www.ryde.nsw.gov.au/environment/water/desalination.htm, http://en.wikipedia.org/wiki/Multi-stage_flash_distillation,http://www.fwr.org/desal.pdf, http://www.fwr.org/desal.pdf , http://www.chemicals-technology.com/contractor_images/ast/3_heat-exchanger2.jpg , and www.nrdc.org/…/04sum/images/saline_diagram.jpg .

Mercury-A Brief History

Mercury, symbol Hg, is a heavy, silvery d-block element. It is the only metal that is liquid at standard conditions for temperature and pressure. Mercury occurs in mineral deposits throughout the world and it is harmless in an insoluble form, such as mercuric sulfide,HgS, (also known as cinnabar), but it is poisonous in all soluble forms such as mercuric chloride, HgCl2.

Cinnabar

In ancient times it was believed by alchemists, that if mercury could absorb gold, then if eaten, it would give that person the ability to “absorb” life, making him or her immortal. Qin Shi Huang, the first emperor of unified China, feared death and desperately sought the fabled elixir of life. Reportedly, the Emperor died of swallowing a solution of powdered jade and mercury, made by his court scientists and doctors. It is believed that the excess of mercury is what killed him.The ancient Greeks used mercury in ointments; the ancient Egyptians and the Romans used it in cosmetics, primarily to whiten the skin, which sometimes deformed the face. By 500 BC mercury was used to make amalgams with other metals.

In Lewis Carrol’s Alice’s Adventures in Wonderland, the character “Hatter” is considered a play on words inspired by the phrase; “as mad as a hatter”.  This phrase originated from the symptoms of the felt workers who suffered from mercury poisoning in the hat making process.

From the 17th to the mid 19th century, a process called “carroting” was used to make the felt used in felt hats. Animal skins were rinsed in an orange mercuric nitrate, Hg(NO3)2·2H2O , to separate the fur from the pelt and mat it together. The mercury in this solution consolidated the fur which was then passed through wet rollers causing the fur to felt. These rolls were then dyed and cut into shapes to make hats. The entire process was incredibly toxic, severely damaging the central nervous system, and it was impossible for hatters to avoid inhaling the mercury fumes given off during the process.

Often hatters and mill workers suffered neurological damage due to these fumes. Symptoms of this mercury poisoning included excessive timidity, diffidence, increasing shyness, loss of self-confidence, anxiety, and a desire to remain unnoticed. The patient also had a pathological fear of being ridiculed. The United States Public Health Service banned the use of mercury in the felt industry in December 1941.

18th and 19th Century Hats

Interestingly, Lewis Carrol’s eccentric extroverted character, does not display these classic mercury poisoning symptoms.

In the early 1900’s mercury was used extensively in hydraulic gold mining, in order to help the gold to sink through the flowing water-gravel mixture. Thin mercury particles may form mercury-gold amalgam and therefore increase the gold recovery rates. Large scale use of mercury in gold mining stopped in the 1960s.

Through the process of biomagnification, levels of mercury absorbed by the food fish eat are concentrated in the fish’s system. Therefore when the fish are consumed by a human, there is the potential that dangerous levels of mercury will be absorbed. As high levels of elemental mercury can be particularly toxic to unborn or young children, it was recommended in 1997 by the FDA that women who are pregnant and young children, avoid eating more than one average meal of fish per week.

Today, Mercury is used in thermometers, barometers, manometers and in various other scientific apparatus. However, concerns about the element’s toxicity have led to mercury thermometers and other mercury-based instruments being largely phased out in clinical environments, in favour of alcohol-filled, or digital-based instruments. It remains in use in a number of other ways in scientific and scientific research applications, and in material for dental restoration. Mercury is also widely used in the manufacture of mascara. In 2008, Minnesota became the first state in the US to ban intentionally added mercury in cosmetics, giving it a tougher standard than the federal government.

For me the allure of this infamous element comes from its ability to fascinate humans for so long. Though incredibly useful, the most important property of this metal is that regardless of all the dangers, humans are drawn to this element. It also demonstrates a fantastic development of human thought relating to scientific discovery.

Mercury

Quicksilver (mercury in liquid form)

Works Cited:
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