Purity and Purifications of Solids Using Melting Points. free essay sample

Purity and purifications of solids using melting points. Tatyana Aleksandrova CHE 337, Section 001 Department of Chemistry Portland State University, Portland, OR ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? Abstract Melting points of Naphthalene/Biphenyl mixtures differing in their percent compositions were observed and plotted on a graph that indicated eutectic point of the mixture to be at 50 mole percent Naphthalene. Using melting point technique to identify mixture Unknown H was determined to be 3-ethoxy-4-hydroxybenzaldehyde. Introduction Melting point is a technique used by chemists to identify unknown substance. Compounds depending on their chemical structure have a specific melting point. Pure substance has a sharp melting point with the maximum range of 5? C. Mixtures on the other hand have wider range. Based on these concepts unknown mixtures/substances can be determined by combining them with the substance of the known melting point. Experimental Section Materials and Instruments: Melt Temp device used to electrically heat up substance to a known temperature. We will write a custom essay sample on Purity and Purifications of Solids Using Melting Points. or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page Glass capillary to hold substance in a Melt Temp while heating. Naphthalene Biphenyl Unknown H Naphthalene and Biphenyl melting point determination. Using procedure for melting point determination with Mel-Temp on p. 43-45 in FFF melting points of pure Naphthalene, pure Biphenyl and mixtures of the two were observed and recorded. Mixtures of Naphthalene and Biphenyl according to their mass percent used in experiment: 10% Naphthalene, 90% Biphenyl 30% Naphthalene, 40% Biphenyl 50% Naphthalene, 50% Biphenyl 70% Naphthalene, 30% Biphenyl 90% Naphthalene, 10% Biphenyl Values of melting points obtained in the observation were recorded in Table 1 and plotted into Graph 1. Identification of an Unknown using Mixture Melting Points. MP of unknown H was determined using procedure indicated on p. 43-45 in FFF. Two known samples with the closest to unknown H mps were determined. Two mixtures were prepared, each combining unknown with the known sample in 50/50 proportion. MP of each mixture was observed and recorded. Mixture that had sharp melting point was mixture that contained identical parts. Results and discussion Melting points for mixtures containing different percent of Naphthalene to Biphenyl were observed, recorded, averaged and graphed in Table 1 and Graph 1. Average was taken from several results obtained by organic chemistry lab. Table 1. Average melting point specific to % Naphthalene in Naphthalene-Biphenyl mixture % Naphthalene inNaphthalene-Biphenyl mixture (%)| Corresponding Melting point (Â °C )| 0| 68. 09| 10| 62. 36| 30| 53. 88| 50| 47. 74| 70| 50. 99| 90| 73. 55| 100| 78. 87| Mole Percent of Naphthalene Temperature (C) Graph 1. Melting Point Diagram for Naphthalene and Biphenyl. Observed melting points of pure Naphthalene and Biphenyl (in Table 1) are consistent with CRC Handbook1, that indicates melting temperatures for these substances at 80. 2Â °C and 71. 0 Â °C, respectively. Based on the graph above eutectic point lies at 50% mole percent Naphthalene. Class results were averaged, therefore one inaccurate result would effect the average point, this could be a potential source of error in the experiment. However, class average for MP of pure substances came close to values in CRC Handbook. Another Source of error is limited data points that were observed. Best fitted line illustrated in Table 1 can contain a source of error due to the insufficient number of data points. Using Melting point technique unknown H, was determined to have MP in the range from 73. 3 to 75. 4. Based on its melting point it was mixed with 3-Ethoxy-4-hydroxybenzaldehyde and pure Biphenyl. Results are reported in Table 2. Substance tested| Melting Point ( Â °C )| Unknown H/3-Ethoxy-4-hydroxybenzaldehyde| 76. 1 78. 7| Unknown H/ pure Biphenyl| 55. 0 59. 6| Table 2. Melting points of mixtures containing unknown H in 50/50 proportion. Based on the fact that mixture with 3-Ethoxy-4-hydroxybenzaldehyde had relatively close range of (76. 1 Â °C 78. 1 Â °C) with 2. 5 Â °C difference in ending values, which can be considered as a sharp point, unknown H is 3-Ethoxy-4-hydroxybenzaldehyde. Conclusion Melting point is a technique used to identify pure substances by observing ranges of melting points as it was done in mixtures of Naphthalene and Biphenyl. Eutectic point, however, should be kept in my when testing for pure substances, for eutectic compositions can mislead results of the test if nothing else is considered. Biphenyl’s on this technique unknown H tested was determined to be 3-Ethoxy-4-hydroxybenzaldehyde based on its sharp MT. Questions: 1. a) Examples in which a pure substance could give a broad melting range: 5 mole percent of Naphthalene to 95 mole percent of Biphenyl (which is good percentage of purity) has a broad melting range. b) Example of a situation in which an impure substance melts sharply: Mixture of 60 mole percent of Naphthalene and 40 mole percent of Biphenyl. Mixture has eutectic composition. 2. Eutectic mixture – mixture in which proportions of its constituents allow a uniform melting point for that mixture. MP range is sharp, despite the fact that mixture is impure. 3. Effects of the impurities on melting behavior of benzoic acid: MP Benzoic Acid – 122 Â °C a. Fragments of crushed glass – MP of crashed glass is around 1500 Â °C, which is a lot higher than MP of B. A. Due to the big difference in melting points between substances, glass will stay insolvent. MP of B.. A. will not change, it will melt with pieces of glass in the substance. . Residual recrystallization solvent –mostly contains water, which would lower the melting point of B. A. c. Filter paper fibers – MP of B. A. will not change, due to large differences in Mps. Fibers will remain in the melted B. A. d. Particles of ceiling plaster that fell into the sample – MP of B. A. will not change due to difference in Mps. 4. FFF, 2. 8, p. 48: Suppose you are taking a MP and c ompound disappears.. What happened? Compound was a volatile compound that changes from solid to gaseous form without going through liquid form (sublimed). To prevent this one end of the capillary should be sealed. 5. Because compound is in clusters, it takes more heat to go through layers to heat up a compound. However, more heat doesn’t mean higher melting point. It has more substance to heat. 6. Even if two compounds have the same melting point, if they are not identical MT of their mixture will be depressed. Therefore, mixture that shows the same MT as an unknown would identification. References 1CRC Handbook, CRC Press: New York, 1999.

Debate against death penalty essays

Debate against death penalty essays The death penalty has always been a very controversial issue. Death sentences are usually handed out to people who have been found guilty of capital crime. However it is not so easy to consider death penalty as an easy way to punish the guilty. If the death penalty is to condemn it does not mean that the guilty party should be released or allowed some sympathy. It would defeat the purpose, as it would be using violence to counter violence. How can we tell if a man/woman convicted for murder is really guilty' There may be a margin of error. Would it be right to wrongfully accuse someone and execute him/her' We should look at the ethical downsides This has been a very serious problem for civil rights groups, religious figures and other people who oppose the death penalty. The death penalty has a lot of ethical and religious matters tied to it. There are many who support death penalty while others oppose it staunchly. The death penalty violates the constitutional right of a human being. It is more of a barbaric and cruel punishment against a living human being and can be classified as one of the worst acts of human nature. It defies all religious conventions, as it's not the right of the state to play God and decide who should live and who should be executed. When the law chooses its path it can be biased too as it may be too discriminatory. Civil rights unions have campaigned against the death penalty. The argument against the death penalty is that even though it's a punishment for a murder, it won't hurt to punish the murderer with a less harsh sentence. A death penalty would have been justifiable if it were able to prevent future crimes. However this has not been the case so far. The cruel irony is that the United States of America, which claims to the champion of democracy in the west, is the only nation, which indulges in this cruel and unusual There have been cases where the def...

Make Non-Toxic Glue From Milk

Make Non-Toxic Glue From Milk Use common kitchen materials to make your own glue. Add vinegar to milk, separate the curds, and add baking soda and water. Voila, youve got glue! Difficulty: AverageTime required: 15 minutes Materials 1/4 cup hot water1 tbsp vinegar2 tbsp powdered dry milk1/2 tsp baking sodaWater How to Make It Mix 1/4 cup hot tap water with 2 tbsp powdered milk. Stir until dissolved.Stir 1 tbsp of vinegar into the mixture. The milk will begin to separate into solid curds and watery whey. Continue stirring until the milk is well-separated.Pour the curds and whey into a coffee filter positioned over a cup. Slowly lift the filter, draining the whey. Keep the curd, which is in the filter.Squeeze the filter to remove as much liquid as possible from the curd. Discard the whey (i.e., pour it down a drain) and return the curd to a cup.Use a spoon to break the curd into small pieces.Add 1 tsp hot water and 1/8 to 1/4 tsp baking soda to the chopped curd. Some foaming may occur (carbon dioxide gas from the reaction of baking soda with vinegar).Mix thoroughly until the glue becomes smooth and more liquid. If the mixture is too thick, add a bit more water. If the glue is too lumpy, add more baking soda.The finished glue can vary in consistency from a thick liquid to a thick paste, depending on how much water has been added, how much curd was present, and how much baking soda was added. Use your glue as you would any school paste. Have fun!When not in use, cover your cup of glue with plastic wrap. Over time, its consistency will become smoother and more clear.Unrefrigerated glue will spoil after 24 to 48 hours. Discard the glue when it develops a spoiled milk smell. Tips for Success The separation of curds and whey works best when the milk is warm or hot. This  is why powdered milk is recommended for this project.If the separation doesnt work well, heat the milk or add a bit more vinegar. If it still doesnt work, start again with warmer water.Clean dried glue by loosening/dissolving it in warm water and wiping it away. Glue will wash out of clothes and off surfaces. Reaction Between Milk and Vinegar Mixing milk and vinegar (weak acetic acid) produces a chemical reaction that forms a polymer called casein. Casein is essentially a natural plastic. The casein molecule is long and pliable, which makes it perfect for forming a flexible bond between two surfaces. The casein curds may be molded and dried to form hard objects that are sometimes called milk pearls. When a small amount of baking soda is added to chopped curd, the baking soda (base) and residual vinegar (acid) participate in an acid-base chemical reaction to produce carbon dioxide, water, and sodium acetate. The carbon dioxide bubbles escape, while the sodium acetate solution combines with the casein curds to form a sticky glue. The thickness of the glue depends on the amount of water present, so it can be either a sticky paste (minimal water) or a thin glue (more water).

Ethical Aspects of Euthanasia Research Paper Example | Topics and Well Written Essays - 1000 words

Ethical Aspects of Euthanasia - Research Paper Example Voluntary euthanasia takes place when death is hastened at the request of the patient. The ethical issues that arise are the respect for individual autonomy, as well as the obligation of the medical practitioners to respect patients’ informed choices. Euthanasia claims to relieve the patient of suffering. It is also argued that if a patient has the right to choose and make informed decision about his medical treatment, he also has the right to decide when to die (Chaloner, 2007). The opponents claim that this could have a damaging effect on the individual and the society. The opponents argue that palliative care should be improved but in terminal cases, no amount of medicine would make any difference. Moreover, the psychological need of the terminally ill patients to be relieved of the suffering should be of equal importance as the physiological needs. This is individual autonomy and an individual must have the freedom to do what he wants to and when he wants to do. John Stuar t’s Harm Principle also asserts that the individual has a right over his own body and mind. This principle restricts the power of physicians and others in the medical field to arrive at decisions about the patient when the decision affects none other than the patient himself. Autonomy again gives rise to certain apprehensions. For an individual to arrive at the decision, he should be competent enough to decide on a course of action. Is he in the right frame of mind? Secondly, if autonomy of the patient is respected, the autonomy of the medical professionals also needs to be respected. Hence, if the autonomy of the doctors is also respected the patient loses the right to receive assistance to die. Rights and duties are interwoven. Hence, it can also be interpreted that the health professionals have a duty to assist the terminally ill patients to die. Other arguments that abound are that a competent

Sub-Prime Mortgage Crisis and the East Asia Research Paper

Sub-Prime Mortgage Crisis and the East Asia - Research Paper Example The subprime mortgage crisis in the United State was more severe than the great depression because several assets and derivatives had been purchased and sold in the unstable market. Moreover, the subprime mortgage crisis had several liquidity risks compared with that of the exchange traded products. According to Justin and Boris (2011), commercial banks finance in the East Asia asks for the mortgages without considering the credit evaluation of the borrowers. Thus, the paper will evaluate the financial crisis issues that were triggered from the U.S sub-prime mortgage crisis, and affected the East Asian economy. The sub-prime mortgage crisis The sub-prime mortgage crisis was a result of the speculative issues in the housing market that commenced in the United State in 2006. It has caused severe impact across the East Asia countries in the form of financial crisis and the country’s credit crisis. Justin and Boris (2011) indicate that the forces caused by the sub-prime mortgage c risis will probably run out of control for years, causing the collateral damage. The disruption in the East Asia countries credit market is of historic proportions and will have significant economic impacts. Moreover, the crisis has caused essential societal changes that affect the consumer habits and the values. Justin and Boris (2011) indicate that the East Asia economy was affected where the GDP was recorded 4.2, 4.8, 5.7 and 1.9 per cent from 2005 to 2008. This led to the ever recorded a decrease in GDP in 2009 that amounted to -4.0 since 1980. Therefore, this crisis has significantly affected the Europe and Asian countries, and most of the Asian countries have rearranged their financial and banking industry. Delgado and Burge (2009) claim that the proximate cause of the sub-prime mortgage crisis was the busting of the housing issues in the East Asia during the summer of 2007 when subprime defaults commenced to rise and foreclosures increased. It then spread to prime loans and o ther types of consumer credit, and the financial institutions with the subprime related products were severely affected. The Asian countries were severely affected by the sub-prime mortgage crisis during the early stage of the crisis because the banks were not exposed to the dangerous assets that were engineered and crafted in the United State. According to Delgado and Burge (2009), the data gathered in the Economist and Financial Times, the $500 billion was written off by banks globally in the 2008. The financial institutions in Japan accounted for only five percent, and its sectors were relatively resilient. The global financial crisis has affected the China and Japan very strongly as they stand among the most opens in the world. Foreign capital inflows declined significantly as commercial banks and foreign institutional investors withdrew funds to meet redemptions in their countries. According to Delgado and Burge (2009), private capital flows in China slowed from $516.7 billion to 2007 to an estimated $134.4 billion in 2008. Table of the GDP of the East Asia countries 2007 2008 2009 China 11.9 9.7 8.5 Japan 2.1 0.5 -0.2 Korea 5.6 3 3.9 2.1 Modified from: IMF (2008a) According to Ghon (2008), the Banking leading declined that was as a result of the direct and indirect equities. During 2009, the capital flows were estimated to be only $44.1 billion, and in the beginning of 2008, stock markets declined by about 62 percent in China (Ghon, 2008). Thus, the Chinese stocks markets had been the worst performer in

Book Report on Wreck! :: essays research papers

First Entry – Suggestion Number 1 – Page 50 This fiction book is called â€Å"Wreck† and was written by Allan Bailie. The main characters are Ian Foster and Reene Thompson, they are two normal teenagers. Reene was told to baby-sit Ian while his parents are away. During this period a cyclone hits Albatross Beach and they barely survive it. Soon they seek shelter in a rusty old freighter on the beach. After, the cyclone erupts again and sets the boat out to sea. While on the boat they experience many strange happenings and realise they are not alone. Second Entry – Suggestion Number 6 – Page 80 I believe the writer was trying to keep suspense and did this by not giving any extra info and by putting in a few false alarms to keep you on your toes. The writer is also very descriptive which adds greats atmosphere and further suspense. I think the writer has a good imagination to be able to write in such a way. Another skill the author has is, he knows when and when not to be descriptive, that helps because a whole page description on something that has no relevance at all is not necessary Third Entry – Suggestion Number 5 – Page 100 Ian is shy and doesn’t seem very confident in the book; Ian explains it’s probably because of his dad who’s always putting him down because he can’t do something right. There isn’t mush about his interest in the book because the author keeps to the story line most of the time. Ian is afraid that he isn’t to his father’s expectations and that his father hates him. His experiences throughout the book make him a stronger person and I think he’s better for it. Reene also helps shape Ian into a better person. She is responsible, outspoken and strong-willed, Ian picks ups picks up a bit of it. Ian comes out to have a stronger mind, isn’t as reliant on others and isn’t afraid to voice his opinions. Fourth Entry – Suggestion Number 8 – Page 120 To me the ending wasn’t much of a surprise because they were on a boat with an unknown monster, they defeat the monster and are rescued which wasn’t much of an ending. This of course doesn’t mean the book is boring, just predictable. There are also many little things that happen along the way to keep this book interesting enough to keep reading.

Psychology-Decision Making Essay

Abstract   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   How does it happen that managers take decisions which lead them to failures? What decision-making mechanisms do they inactivate when they take such decisions? This paper is aimed at analyzing these psychological implications. Psychology Decision Making   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Introduction  Ã‚  Ã‚     Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   It is not rare that managers take decisions which lead them to failure. These failures often become the headlines and the top stories of newspapers and magazines. However, has anyone analyzed the psychological implications of such decisions? What psychological theories could explain such managers’ behavior, and what useful recommendations could be drawn from such cases?   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Problem identification   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   The case of Sears, when owned by Edward S. Lampert, is the most recent example of a large managerial mistake, having led to significant financial and economic losses. On January 29, 2008 Lampert pushed out his chief executive, but what is more important, he took decision to distance himself from the day-to-day management of his enterprise. â€Å"Until now, the heads of several major departments, like marketing and merchandising, reported directly to Mr. Lampert, even though he has no background in retailing or advertising† (Barbaro, 2008). It is crucial to understand, how Lampert came to the idea of day-to-day management of his enterprise, although he did not have enough professional skills for that    Theoretical background   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   It is stated, that â€Å"we are likely, social constructed individuals. Our experiences, our cultures, our social order, shape our motivations, our desires, and our beliefs about the world we encounter† (Plous, 1993). Our management decisions are shaped are also shaped under the impact of business environment and the objectives we expect to meet in our management activity. We tend to take decisions, which are primary based on our perception of the world around us (Connolly, 2000). One of the major problems in management decision making is in that a person can hardly be objective in taking decisions. The lack of objectivity leads to the situation, when we do not take into account multiple environmental factors, impacting our decisions.   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Evidently, there cannot be any better explanation to Lampert’s decision, that the self-perception theory. This theory deals with the human perceptions and the ways they incorporate their perceptions into their daily behavior (Plous, 1993). To be clear, Lampert’s expectations and beliefs into his managerial skills and the ability to cope with a large retail enterprise were not justified from the start. In this case, the major question to be answered was â€Å"what am I to do to make this enterprise profitable?† Trying to answer this question, and taking decisions in the discussed framework, Lampert has concluded that the best solution for the situation would be tying himself to the daily company’s activity. Moreover, it was not enough for him to stay ahead; he had to manage, but this decision lacked theoretical and practical foundations. This is how Lampert’s pseudo opinions impacted the overall performance of the company (Plous, 1993). Respondents are influenced by pseudo opinions when they do not know much about the issue or when they know nothing about it (Plous, 1993). In Lampert’s case, attribution heuristics has greatly contributed into the negative decision outcomes: Lampert was obviously justifying his behavior as situationally-produced. As a result, he has underestimated the lack of his managerial skills (Plous, 1993).   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Critical thinking is the integral part of the decision making process. â€Å"Most international managers find it extremely challenging to evaluate a written or spoken commentary on a hot topic because both sides of the controversy seem to have good arguments† (Safi & Burrell, 2007). Has Lampert’s decision been caused by critical thinking approach? Definitely, it has: for a long period of time, Sears was criticized for lacking a management team with retail experience and for Lampert’s being a micromanager who hampered the business (Barbaro, 2008). As a result, Lampert was driven to the situation in which he had to admit his managerial mistakes due to the two facts: the external criticism, and the objective financial data confirming the $14 million financial losses.   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Recommendations   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   The case of Edward S. Lampert is a brilliant example of a situation, in which successful manager has overestimated his skills and has not applied any critical thinking approach before the decision was made. As a result, numerous pseudo opinions and the lack of objective information have led to significant gaps in the company’s performance. In order to take a good decision, a manager must â€Å"understand, what result is desirable and the tools available to us for making good decisions† (Safi & Burrell, 2007). There are several recommendations for a manager in similar situations. First, it is crucial that the manager avoids pseudo opinions. In this aspect, the wording of the question to answer is very important. In order to create effective decisions, managers must be able to formulate the questions. Properly wording the issue crucially impacts the effectiveness of the chosen answers, and as a result, the managerial activities which lead or do not lead to business success. â€Å"Be honest with yourself about the agendas and motives. Are you really gathering information to help you make a smart choice, or are you just looking for evidence confirming your preconceived notions?† (Safi & Burrell, 2007). Not only objectivity and evaluation of one’s skills have led Sears to failure. It is also the inability to properly formulate the goals of such actions: what aims did Lampert have in his actions? Did he want to promote his enterprise profitability or himself as a successful manager? He had to answer those questions before he undertook any real actions which later almost pushed the company into the flow of negative consequences.   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Conclusion   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   In his decision to quit day-to-day management of Sears, Lampert has finally come to one of the crucial elements in the decision-making process: he was able to recall the key facts and decision-making variables. The list of these variables included financial indices and persistent criticism of Sears’ performance. As a result, Lampert was finally able to take the best decision possible in the problematic situation. However, it is still unclear whether hiring a new CEO was based on any objective grounds or would require thorough re-consideration in the nearest future. One may hope that this re-consideration will not be caused by a new management decision-making failure. References Barbaro, M. (2008). Sears’ chairman will take a step back. The New York Times. Retrieved February 1, 2008 from http://www.nytimes.com/2008/01/29/business/29sears.html?ref=business–qG4vaywTPkZypAw Connolly, T. (2000). Judgment and decision making: An interdisciplinary reader. Cambridge University Press. Plous, S. (1993). The Psychology of judgment and decision making. McGraw-Hill. Safi, A. & Burrell, D.N. (2007). Developing advanced decision-making skills in international leaders and managers. Vikalpa, vol. 32, no. 3, pp. 1-8.