Tuesday, March 17, 2020

Coming to America essays

Coming to America essays Social class in modern society is a very interesting topic to explore. There are many ways to understand concepts that describe class, but I believe the best way in doing this is by comparisons through movies. I believe one of the best movies that distinguishes social characteristics and relates social theories on class is Coming to America starring Eddie Murphy and Arsenio Hall. The movie is about an African prince who comes to Brooklyn in search of an American bride who will love him for who he is, rather than for his wealth and royal status. He poses as a poor bus boy in a restaurant in NY. He falls in love with his bosses daughter, but his boss is rich and thinks he is poor so he doesnt want them to become a couple. He wants her to marry some rich man from a wealthy family. This movie shows how people use SES, or socioeconomic status to make class judgments. Such as when her father believes the prince is poor, uneducated, and has no occupational prestige he thinks he is not good enough for his daughter, as soon he find out he is a wealthy prince he thinks he is the best guy in the world. At first the father would only see the prince at work, so he assumed he was of lower class, because he worked at a fast food restaurant and that is also not a prestigious job, but a prince on the other hand is a prestigious add a long, its like having dr. before your name, and if youre a prince wealth is associated along with your name. This is based on the objective approach of class. Many people also believe certain groups of people are poor like for example single mothers. Race and social class are also said to have close ties. Even though 2/3 of all poor people are white it is said the percentage of poor in minorities is disproportioned, according to Second Edition Sociology, by Linda L. Lindsey and Stephen Beech, 11 percent of whites are poor but 26.5 percent of blacks are poor. The movie also illustrates this, bu...

Sunday, March 1, 2020

Beers Law Definition and Equation

Beer's Law Definition and Equation Beers Law is an equation that relates the attenuation of light to properties of a material. The law states the concentration of a chemical is directly proportional to the absorbance of a solution. The relation may be used to determine the concentration of a chemical species in a solution using a colorimeter or spectrophotometer. The relation is most often used in UV-visible absorption spectroscopy. Note that Beers Law is not valid at high solution concentrations. Other Names for Beers Law Beers Law is also known as the Beer-Lambert Law, the Lambert-Beer Law, and the  Beer–Lambert–Bouguer law. The reason there are so many names is because more than one law is involved. Basically, Pierre Bouger discovered the law in 1729 and published it in Essai doptique sur la gradation de la lumià ¨re. Lambert quoted Bougers discovery in his Photometria in 1760, saying absorbance of a sample is directly proportional to the path length of light. Even though Lambert didnt claim discovery, he was often credited with it. August Beer discovered a related law in 1852. Beers law stated the absorbance is proportional to the concentration of the sample. Technically, Beers law relates to only to concentration, while the Beer-Lambert law relates absorbance to both concentration and sample thickness. Key Takeaways: Beer's Law Beers law states that the concentration of a chemical solution is directly proportional to its absorption of light.The premise is that a beam of light becomes weaker as it passes through a chemical solution. The attenuation of light occurs either as a result of distance through solution or increasing concentration.Beers law goes by many names, including the Beer-Lambert law, Lambert-Beer law, and Beer-Lambert-Bouguer law. Equation for Beers Law Beers Law may be written simply as: A ÃŽ µbc where  A is absorbance (no units)ÃŽ µ is the molar absorptivity with units of L mol-1  cm-1 (formerly called the extinction coefficient)b is the path length of the sample, usually expressed in cmc is the concentration of the compound in solution, expressed in mol L-1 Calculating the absorbance of a sample using the equation depends on two assumptions: The absorbance is directly proportional to the path length of the sample (the width of the cuvette).The absorbance is directly proportional to the concentration of the sample. In this example of the Beer-Lambert law, a green laser is attenuated as it passes through a solution of Rhodamine 6G. Amirber How to Use Beers Law While many modern instruments perform Beers law calculations by simply comparing a blank cuvette with a sample, its easy to prepare a graph using standard solutions to determine the concentration of a specimen. The graphing method assumes a straight-line relationship between absorbance and concentration, which is valid for dilute solutions.   Beers Law Example Calculation A sample is known to have a maximum absorbance value of 275 nm. Its molar absorptivity is 8400 M-1cm-1. The width of the cuvette is 1 cm. A spectrophotometer finds A 0.70. What is the concentration of the sample? To solve the problem, use Beers law: A ÃŽ µbc 0.70 (8400 M-1cm-1)(1 cm)(c) Divide both sides of the equation by [(8400 M-1 cm-1)(1 cm)] c 8.33 x 10-5 mol/L Importance of Beers Law Beers law is especially important in the fields of chemistry, physics, and meteorology. Beers law is used in chemistry to measure the concentration of chemical solutions, to analyze oxidation, and to measure polymer degradation. The law also describes the attenuation of radiation through the Earths atmosphere. While normally applied to light, the law also helps scientists understand the attenuation of particle beams, such as neutrons. In theoretical physics, the Beer-Lambert law is a solution to the Bhatnagar-Gross-Krook (BKG) operator, which is used in the Boltzmann equation for computational fluid dynamics. Sources Beer, August (1852). Bestimmung der Absorption des rothen Lichts in farbigen Flà ¼ssigkeiten (Determination of the absorption of red light in colored liquids). Annalen der Physik und Chemie. 86: 78–88.Bouguer, Pierre (1729). Essai doptique sur la gradation de la lumià ¨re. Paris, France: Claude Jombert. pp. 16–22.Ingle, J. D. J.; Crouch, S. R. (1988). Spectrochemical Analysis. New Jersey: Prentice Hall.Lambert, J. H. (1760). Photometria sive de mensura et gradibus luminis, colorum et umbrae [Photometry, or, On the measure and gradations of light, colors, and shade]. Augsburg (Augusta Vindelicorum), Germany: Eberhardt Klett.Mayerhà ¶fer, Thomas Gà ¼nter; Popp, Jà ¼rgen (2018). Beers law - why absorbance depends (almost) linearly on concentration. Chemphyschem. doi:10.1002/cphc.201801073