Tin Facts (Atomic Number 50 or Sn)

Tin is silver or gray metal with atomic number 50 and element symbol Sn. It is known for its use for early canned goods and in the manufacture of bronze and pewter. Here is a collection of tin element facts. Fast Facts: Tin Element Name: TinElement Symbol: SnAtomic Number: 50Atomic Weight: 118.71Appearance: Silver metal (alpha, ÃŽ ±) or gray metal (beta, ÃŽ ²)Group: Group 14 (Carbon Group)Period: Period 5Electron Configuration: [Kr] 5s2 4d10 5p2Discovery: Known to mankind since around 3500 BCE Tin  Basic Facts Tin has been known since ancient times. The first tin alloy to gain widespread use was bronze, an alloy of tin and copper. Humans knew how to make bronze as early as 3000 BCE. Word Origin: Anglo-Saxon tin, Latin stannum, both names for the element tin. Named after Etruscan god, Tinia; denoted by the Latin symbol for stannum. Isotopes: Many isotopes of tin are known. Ordinary tin is composed of ten stable isotopes. Twenty-nine unstable isotopes have been recognized and 30 metastable isomers exist. Tin has the greatest number of stable isotopes of any element, due to its atomic number, which is a magic number in nuclear physics. Properties: Tin has a melting point of 231.9681 °C, boiling point of 2270 °C, specific gravity (gray) of 5.75 or (white) 7.31, with a valence of 2 or 4. Tin is a malleable silvery-white metal which takes a high polish. It possesses a highly crystalline structure and is moderately ductile. When a bar of tin is bent, the crystals break, producing a characteristic tin cry. Two or three allotropic forms of tin exist. Gray or a tin has a cubic structure. Upon warming, at 13.2 °C gray tin changes to white or b tin, which has a tetragonal structure. This transition from the a to the b form is termed the tin pest. A g form may exist between 161 °C and the melting point. When tin is cooled below 13.2 °C, it slowly changes from the white form to the gray form, although the transition is affected by impurities such as zinc or aluminum and can be prevented if small amounts of bismuth or antimony are present. Tin is resistant to attack by sea, distilled, or soft tap water, but it will c orrode in strong acids, alkalis, and acid salts. The presence of oxygen in a solution accelerates the rate of corrosion. Uses: Tin is used to coat other metals to prevent corrosion. Tin plate over steel is use to make corrosion-resistant cans for food. Some of the important alloys of tin are soft solder, fusible metal, type metal, bronze, pewter, Babbitt metal, bell metal, die casting alloy, White metal, and phosphor bronze. The chloride SnCl ·H2O is used as a reducing agent and as a mordant for printing calico. Tin salts may be sprayed onto glass to produce electrically conductive coatings. Molten tin is used to float molten glass to produce window glass. Crystalline tin-niobium alloys are superconductive at very low temperatures. Sources: The primary source of tin is cassiterite (SnO2). Tin is obtained by reducing its ore with coal in a reverberatory furnace. Toxicity: Elemental tin metal, its salts, and its oxides present low toxicity. Tin-plated steel cans are still widely used for food preservation. Exposure levels of 100 mg/m3 are considered immediately dangerous. Legal permissible exposure from contact or inhalation is typically set around 2 mg/m3 per 8-hour work day. In contrast, organotin compounds are highly toxic, on par with that of cyanide. Organotin compounds are used to stabilize PVC, in organic chemistry, to make lithium ion batteries, and as biocidal agents. Tin  Physical Data Element Classification: MetalDensity (g/cc): 7.31Melting Point (K): 505.1Boiling Point (K): 2543Appearance: silvery-white, soft, malleable, ductile metalAtomic Radius (pm): 162Atomic Volume (cc/mol): 16.3Covalent Radius (pm): 141Ionic Radius: 71 (4e) 93 (2)Specific Heat (20 °C J/g mol): 0.222Fusion Heat (kJ/mol): 7.07Evaporation Heat (kJ/mol): 296Debye Temperature (K): 170.00Pauling Negativity Number: 1.96First Ionizing Energy (kJ/mol): 708.2Oxidation States: 4, 2Lattice Structure: TetragonalLattice Constant (Ã…): 5.820 Sources Emsley, John (2001). Tin. Natures Building Blocks: An A–Z Guide to the Elements. Oxford, England, UK: Oxford University Press. pp. 445–450. ISBN 0-19-850340-7.Greenwood, N. N.; Earnshaw, A. (1997). Chemistry of the Elements (2nd ed.). Oxford: Butterworth-Heinemann. ISBN 0-7506-3365-4.Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.

The Meaning of It Research Paper

The Meaning of It Research Paper A research paper involves surveying a field of knowledge so as to get the best possible info in that area. In case you have any questionnaires for your research proposal or some other documents associated with your investigation, include all of them in the appendices. Sports research paper topics cover a wide variety of fields. So, you've decided to purchase research papers online. The specific first issue to producing amazing research papers are going to be to pick a great issue. The exact same applies inadvertently in the event that you bump into each other. Research papers are trying, but in addition they have the capacity to be somewhat rewarding. What You Don't Know About It Research Paper A research paper has a study that normally starts with the invention of a research paper outline. If you like science, you're guaranteed to talk non-stop about it. To compose a great research paper you want to be confident in your argument. 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Free Catch

Free Catch-22s: Caught in the System Catch-2 Essay 2Catch-22 Caught in the System The major theme of Catch-22 is the individual vs. the system. Heller creates a setting in which the characters represent either exploiter or exploited. The struggle of characters to maintain their individuality is a thread which holds the novel together. To the military system, soldiers are not people; theyre just uniforms and numbers. Oddly, enemies are found fighting alongside each other. The catch itself is representative of what oppresses the soldiers who are fighting to escape the war. The catch is used as justification for every violation of human rights. The catch means whatever they(the system) want it to. Characters are persuaded to believe in the system rather than oppose it. As Yossarian discovers, Catch-22 did not exist. ..but it made no difference. What did matter, is that everyone thought it did, and that was much worse, for there was no object or text to criticize, attack, amend, hate, revile, spit at, rip to shreds, trample upon or burn up(419). The only possible way to affect the system is to cease to serve it, Yossarian discovers. As stated by Vance Ramsey, people react to meaninglessness by renouncing their humanity, becoming cogs in the machine(178). On a consistent basis, each chapter of Catch-22 depicts a scenario of the individual vs. the system. According to one critic,Each chapter carries a single character a step nearer madness or death or both,(Frank 81). Walsh clarifies, In the world of Catch-22, it is all too easy to become the man in white a reference to a wounded hospitalized man, a mass of bandages with a mouth hole, a tube for - a name and a military rank(203). The individual vs. the system and the loss of individuality are reoccurring themes in Hellers Catch-22. The reoccurrence of these ideas is an important thread that binds this novel together.

Polar Vs. Brown Bear Essays - Bears, Polar Bear, Brown Bear

Polar Vs. Brown Bear There are eight different species of bears found throughout the world: the spectacled bear, the Asiatic black bear, the brown bear (including grizzlies), the polar bear, the sun bear, the American black bear, the sloth bear and the giant panda. Even though most people can distinguish a polar bear from a brown bear by the color of the fur, a lot of people fail to identify all the differences among those two species. Both bears can be perceived as large, clumsy and lumbering beasts with heavily built bodies but short legs, necks and tails. Both of them have rounded ears and noticeably small eyes relative to their large body size. While both of the bears belong to same family, they have several profound differences. They live in different geographical areas, differ in amount of the population, size, physical features, some eating habits, and their behavior toward human beings. The polar bear is found in all of the polar regions of the entire northern hemisphere. This includes Russia, Norway, Greenland, The United States and Canada. Their preferred habitat is in the area where the northern seas meet the shoreline. In this area, there is a constant freezing and thawing of the ice. It is estimated that there are currently somewhere between 20,000 and 40,000 polar bears. The polar bear is the largest member of the bear family, weighing in at between 440 and 1760 pounds with overall body length 11.5 feet. It can grow much larger, however. In fact, there is a record of an adult polar bear weighing over 2200 pounds. Polar bears have a distinctive all white fur which is important camouflage when hunting on the ice pack. Their actual color of the skin is black which is thought to be an adaptation for better heat retention. Compared to the other bears, the neck of polar bear is much longer. This makes it easier for them to keep their heads above water when swimming. Like those of other bears, the ears of the polar bear are round. They are, however, smaller and closer to the head. This also helps the animal to be an exceptional swimmer. The forepaws on a polar bear are very large. With a diameter approaching 12 inches and partial webbing between their toes, polar bears are able to use their front feet much like paddles to propel them rapidly through the water. Polar bears are excellent swimmers. They are able to swim distances greater than 60 miles without a pause to rest, maintaining average speed of 6 miles per hour. On land, they are not as quick as brown bears and appear to have traded off speed for their extremely massive forelegs which they use to break through seal dens and to flip a large seal out of the water. Polar bears have also developed large stomachs with a capacity of more than 150 pounds of food. Their digestive system is also more adapted for processing meat than plant material because they are almost exclusively meat eaters. While out on the ice, their diet consists mostly of marine mammals such as the ringed seals, bearded seals and occasionally a walrus or narwhal. Also, in keeping with their carnivorous nature, the canine teeth, used for seizing and holding prey, are longer, sharper and spaced wider apart than in brown bears. Polar bear are at the top of the arctic food chain with no natural enemies. Because of that, compared to other bears, polar bears are the most aggressive and more willing to consider humans as a prey. In other words, when they see a human, they see a walking meal. Consequently the person attacked is usually killed unless the bear is killed first. The most carnivorous, they are also the most patient and determined all of bears. In some instances they may follow a person for hundreds of miles in order to hunt him down. Out of eight species polar bear is considered to be the most dangerous to human beings. The brown bear has the most widespread distribution in the world of any of the eight bear species. They are found throughout most of the northern hemisphere including North America and Eurasia. Their preferred habitat includes mountain forests,

Hitchcock essays

Hitchcock essays Alfred Hitchcocks Psycho (staring Janet Leigh and Anthony Perkins) is one of the most influential films in motion picture history. Hitchcock uses cinematography, dialogue, costumes and lighting, as well as many other film techniques to thrill the audience and keep them on the edge of their seats from the beginning of the film to the very end. These scenes we have just viewed are a typical example of Hitchcocks great ability to tell a story in a horrific way and haunt the viewers for a long time after their experience with the thrilling movie. He is able to get into the audiences minds and scare them into never wanting to have another shower again. Hitchcocks highly developed cinematography skills make a large contribution to the horrific atmosphere which is present throughout the film. At the start of the film, the camera slowly pans over the city of Phoenix and selects Marion and Sams hotel room. This gives a feeling of randomness and also power, because Hitchcock could have picked any room in the entire city, and he picked this one. If he had chosen to enter any other building, we would never have known Marions story. Chance plays a major role in this film. If we did not enter Marions hotel room, we would never have heard her story, if they didnt need to pay off debts, she wouldnt have stolen the money and if she hadnt stolen the money, she wouldnt have been murdered. This randomness is also displayed later on in the film when Norman reaches for the key to Marions room, and then moves his hand back before selecting the key to cabin number 1. As the camera enters the room, the blinds narrowly conceal the interior, which sets a secretive and scandalous atmosphere. Many close ups and low angle shots are used in the movie, including in this excerpt. Once inside the hotel room, the camera zooms in on Marion and Sam, showing how close they are and almost justifying t...

History islamic art Term Paper Example | Topics and Well Written Essays - 1000 words

History islamic art - Term Paper Example In this paper we will discuss the history of Islamic architecture and different styles of Islamic architecture like Persian, Azerbaijani, Turkistan, Ottoman architecture etc. Islamic architecture began to spread soon after the advent of Islam. Initially mosques were required form Muslims to pray and from that the earliest form of Islamic architecture emerged. The oldest piece of Islamic architecture is The Dome of Rock, which is a shrine in the Old City of Jerusalem built in 691. The Dome of Rock is inspired by influence of Byzantine. When Muslim rulers invaded Spain Islamic architecture expanded to all corners of the world. The main reason for expansion of Islamic architecture was building of mosques. Muslim rulers built mosque wherever they went in order to pray and these mosques became the symbols of Islamic Architecture. Muslim rulers hired local engineers to build their mosques so shades of local art styles can also be seen in Islamic architecture. Islamic architecture therefore sprang through the union of existing art forms and Islamic culture. Calligraphy was also very famous in ancient Islamic times. The use of calligraphy can be seen on walls of mosques and forts that were built by Islamic rulers. Muslims used to write Quranic scripture in different forms and from that sprang the art of calligraphy in Islamic culture. Many famous buildings, forts and mosques have Quranic verses written on walls in beautiful styles. Umayyads were the first to officially introduce religious architecture in their time. They started to introduce new concepts of architecture through the help of existing buildings. The courtyard and other important buildings, for purpose of governance, served as an official start to Islamic architecture. In buildings of this time functionality seems to be an important aspect which tells that buildings were not built for artistic reasons rather they were made for performing services of the

How to snowboard Essay Example | Topics and Well Written Essays - 500 words

How to snowboard - Essay Example Apart from this, the needed accessories include a pair of gloves, a helmet, goggles, wrist guards and a hat. Next is to get into the bindings so that a snowboarder comes at level with the snow. For this, he needs to place his front foot in the flat area of the snow. The straps should be closed for both the toe and the ankle. For step-in bindings, there is a need to step in and roll the foot in a circular position so that it is deemed as safe. Bouncing a few steps in this position would give a general feel as to how it looks. Next is to take the first few baby steps. These steps should have the front foot in the snowboard binding and the back foot out towards the outside. One should start by placing the shoulders and toes in direct linkage with the incline and the snowboard should go in a perpendicular fashion with this incline. After the baby steps, a snowboarder must sit down and strap his feet into the snowboard. Standing up after this and looking towards the snowboard helps at understanding the process faster. At this time, weight must be laid on the heels. Repetition of this step back and forth helps at understanding the snowboarding process. Skating is another step which helps to give an idea about the movement through the flat areas and the snowboarded must know how to skate beforehand. Next step is to think of him as getting out off a chair where he needs to go in an area of inclination and thus secure the front foot towards the binding. Thus the snowboard must be pointed downwards during this activity as it will put the weight on the front foot and glide automatically towards the flat area. After these steps, when the snowboarded starts getting comfortable with the whole process, he must practice until he reaches for the chairlift which will escort him towards the top. At this moment, he needs to observe how the other snowboarders are carrying out their snowboarding activities. After this, the snowboarder is required to slide