Argon Facts (Atomic Number 18 or Ar)

Argon Facts (Atomic Number 18 or Ar) Argon is a noble gas with element symbol Ar and atomic number 18. It is best known for its use as an inert gas and for making plasma globes. Fast Facts: Argon Element Name: ArgonElement Symbol: ArAtomic Number: 18Atomic Weight: 39.948Appearance: Colorless inert gasGroup: Group 18 (Noble Gas)Period: Period 3Discovery: Lord Rayleigh and William Ramsay (1894) Discovery Argon was discovered by Sir William Ramsay and Lord Rayleigh in 1894 (Scotland). Prior to the discovery, Henry Cavendish (1785) suspected some unreactive gas occurred in air. Ramsay and Rayleigh isolated argon by removing the nitrogen, oxygen, water, and carbon dioxide. They found the remaining gas was 0.5% lighter than nitrogen. The emission spectrum of the gas did not match that of any known element. Electron Configuration [Ne] 3s2 3p6 Word Origin The word argon comes from the Greek word argos, which means inactive or lazy. This refers to the extremely low chemical reactivity of argon. Isotopes There are 22 known isotopes of argon ranging from Ar-31 to Ar-51 and Ar-53. Natural argon is a mixture of three stable isotopes: Ar-36 (0.34%), Ar-38 (0.06%), Ar-40 (99.6%). Ar-39 (half-life 269 yrs) is to determine the age of ice cores, ground water and igneous rocks. Appearance Under ordinary conditions, argon is a colorless, odorless, and flavorless gas. The liquid and solid forms are transparent, resembling water or nitrogen. In an electric field, ionized argon produces a characteristic lilac to violet glow. Properties Argon has a freezing point of -189.2Â °C, boiling point of -185.7Â °C, and density of 1.7837 g/l. Argon is considered to be a noble or inert gas and does not form true chemical compounds, although it does form a hydrate with a dissociation pressure of 105 atm at 0Â °C. Ion molecules of argon have been observed, including (ArKr), (ArXe), and (NeAr). Argon forms a clathrate with b hydroquinone, which is stable yet without true chemical bonds. Argon is two and a half times more soluble in water than nitrogen, with approximately the same solubility as oxygen. Argons emission spectrum includes a characteristic set of red lines. Uses Argon is used in electric lights and in fluorescent tubes, photo tubes, glow tubes, and in lasers. Argon is used as an inert gas for welding and cutting, blanketing reactive elements, and as a protective (nonreactive) atmosphere for growing crystals of silicon and germanium. Sources Argon gas is prepared by fractionating liquid air. The Earths atmosphere contains 0.94% argon. Mars atmosphere contains 1.6% Argon-40 and 5 ppm Argon-36. Toxicity Because it is inert, argon is considered to be non-toxic. It is a normal component of air that we breathe every day. Argon is used in blue argon laser to repair eye defects and kill tumors. Argon gas may replace nitrogen in underwater breathing mixtures (Argox) to help reduce the incidence of decompression sickness. Although argon is non-toxic, it is considerably more dense than air. In an enclosed space, it may present an asphyxiation risk, particularly near ground level. Element Classification Inert Gas Density (g/cc) 1.40 ( -186 Â °C) Melting Point (K) 83.8 Boiling Point (K) 87.3 Appearance Colorless, tasteless, odorless noble gas Atomic Radius (pm):Â  2- Atomic Volume (cc/mol): 24.2 Covalent Radius (pm): 98 Specific Heat (20Â °C J/g mol): 0.138 Evaporation Heat (kJ/mol): 6.52 Debye Temperature (K): 85.00 Pauling Negativity Number: 0.0 First Ionizing Energy (kJ/mol): 1519.6 Lattice Structure: Face-Centered Cubic Lattice Constant (Ã…): 5.260 CAS Registry Number: 7440–37–1 Argon Trivia The first noble gas to be discovered was argon.Argon glows violet in a gas discharge tube. It is the gas found in plasma balls.William Ramsay, in addition to argon, discovered all the noble gases except radon. This earned him the 1904 Noble Prize in Chemistry.The original atomic symbol for argon was A. In 1957, the IUPAC changed the symbol to the current Ar.Argon is the 3rd most common gas in Earths atmosphere.Argon is produced commercially by fractional distillation of air.Substances are stored in argon gas to prevent interactions with the atmosphere. Sources Brown, T. L.; Bursten, B. E.; LeMay, H. E. (2006). J. Challice; N. Folchetti, eds. Chemistry: The Central Science (10th ed.). Pearson Education. pp. 276 289. ISBN 978-0-13-109686-8.Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed.). Boca Raton, FL: CRC Press. p. 4.121. ISBN 1439855110.Shuen-Chen Hwang, Robert D. Lein, Daniel A. Morgan (2005). Noble Gases. Kirk Othmer Encyclopedia of Chemical Technology. Wiley. pp. 343–383.Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.

Grapes of Wrath by John Steinbeck essays

Grapes of Wrath by John Steinbeck essays The Grapes of Wrath by John Steinbeck is both a historical and literary depiction of the lives of California migrant workers who became victims to the dry spells that plagued the Dust Bowl regions (Kansas, Oklahoma, Texas, New Mexico, and Colorado) during the 1930s. The novel, through the lead characters, Tom Joad and his family, Steinbeck illustrated life of Oklahomans who migrated to California in search for work and living. However, the Joad family's life served as the symbol' representing all California migrant workers during the period. This is because the novel actually discusses the conflict between the California migrant workers (protagonist) and the white American society (antagonist). Moreover, the novel is also a display of conflict between poverty and wealth, as American society shifts from being an agricultural to urban. Conflict between the migrant workers and white Americans in California stemmed from the threat that the migrants posed for the state's inhabitants: the migration of people from the Dust Bowl regions led to lesser opportunities for work and economic resources for them Tom Joad, the main character of the novel, best represent the migrant worker of the 30s, who was forced to leave his home for want of a better life in California. However, hopes for his family's good fortune in their new life led to disillusionment when he witnessed the sorry' state of migrants in and the ugliness' of California. This realization surfaced as they neared and arrived at the state: "Tom looked about the grimy tents, the junk equipment, at the old cars, the lumpy mattresses out in the sun, at the blackened cans on fire-blackened holes where the people cooked" (286). The inevitable conflict that discrimination among migrant workers finally led to Tom's downfall, when he was (wrongfully) accused of killing Casy. His disillusionment and becoming a fugitive bui...

Art Essay Example | Topics and Well Written Essays - 500 words - 62

Art - Essay Example This report shows the presentation of two undergraduate students during the 11th annual artistry symposium. A light humor at the beginning signals his commencement of the presentation of his research on Italian futurism and fascism. He begins by digging deep into the historical background of both Italian Futurism and its relationship to fascism. According to the speaker, futurism was an artistic movement and later overtaken by social movement and began in Italy in the early 1900s. The movement held in high esteem themes that were linked to contemporary concepts of the future such as violence, young people, technological development and speed. In addition, the movement spearheaded growth in cars, aero plane and a manufacturing city. According to the author, there is an obvious reality when Italian fascism is linked to futuristic movement in Italy. The roughly thirty minute’s presentation comes to an end when the presenter begins to request for questions from the section of the audience. the interaction from the audience is magnificent as the speaker shows great depth by responding to all the questions and engaging in interactive intellectual debates. Perhaps a personal opinion would rate highly the presentation as it is full of content, the structure of the presentation is effective, though it is non visual, a imaginary picturing of the presentation confirms the same. The presenter must have cone the research well as the material presented is packaged properly with a deep historical connections. A humor at the beginning overshadows everything and eliminates nervousness showed by his involvement in the answers at the end of the presentation. She commences the presentation without acknowledging the audience, at least from the limitations provided by the audio recording. A visual one could have provided sufficient chance to observe her body language. However, her presentation is rich in content, but she blubs in between the presentation