Ratios Essay Example | Topics and Well Written Essays - 250 words

Ratios - Essay Example The standardized scope of financial ratios also limits quantitative aspects of the communicated information because the ratios do not communicate exact values of financial information. Profitability is for example expresses in ratios and a firm with relatively lower profit level may report higher profitability ratio than a firm that has recorded higher profit volume. Ratios also assume linear relationship between variables and this mislead stakeholders because most variables are not linearly related (Lee, 2006). Investors could use liquidity ratios to make decisions, on whether to invest in a company or not, by comparing the ratios to the value one. Ratios that are less than one means that a company is overwhelmed by debt, is liable to creditors’ terms and should inform a potential investor against the company. Ratios, which are greater than one, however mean an organization’s independence from creditors’ adverse influences and offers short-term stability for investment. Investors can also use the magnitude of liquidity ratios to understand the level of a company’s liquidity for investment decision because a more liquid company is more secure for investors’ short term interests (Lee,

Please see in other instructions Essay Example | Topics and Well Written Essays - 2500 words

Please see in other instructions - Essay Example One of their more recent forays happened to be one into the financial industry, specifically in the form of Virgin Money plc which, at 17 years old, is still relatively new to this industry. Regardless, it was able to achieve a respectable level of success, if its global expansion in the turn of the millennium is anything to go by. Whatever complaints people might have about the level of customer service, Virgin Money plc must have at least halfway decent services if it has managed to go on operating for the past 17 years. have been getting mixed reactions from clients. Indeed, there are firsthand accounts on various forums and review sites on the internet that tell of the quality of Virgin Moneys services, not all of which are flattering. This being the case, it may be worth examining the customer service management approach taken by Virgin Money. The paper shall first provide a brief, 2-page history of Virgin Money, before introducing the concept of customer relations management - sometimes called customer services management - and how it applies to this firm. An explanation on the groups findings on the matter comes next, as well as on the methods used to obtain data. Rounding the study off is the conclusion, which includes recommendations as to how Virgin Money can improve on its customer service. Virgin Money was established as Virgin Direct by Richard Branson in 1995, and has always been owned by the Virgin Group. Based in the UK, this company deals primarily in banking and other financial services, and has been known as a pioneer of index tracking in its introduction of Personal Equity Plans at relatively affordable prices. Since it expanded its services worldwide early on in the past decade, the company went on to achieve even greater levels of success (BBC News, 2011). As with all companies, Virgin Money had tender beginnings of its own, having first been launched in partnership with Norwich Union in 1995 as Virgin Direct Personal Financial

To what extent does the media assist or limit the conduct of military operations Essay Example for Free

To what extent does the media assist or limit the conduct of military operations Essay Some form of controversy has been regularly generated between the press and the military especially the question of media access to the battlefield. Conflict between reporter and the military is not new. As war correspondents became of age in the Civil War, the military began its determination to protect its operations. The media have often called this determination â€Å"censorship. † The military/media relationship is seriously degraded because of mistrust between the two entities. Sources of this mistrust are analyzed, to include: cultural differences; the perception of biased reporting; misunderstanding and ignorance; and speculation. In any operation there are many aspects of military/media relations which include operational security, the press pool system, logistics, public opinion, etc. However, there has been animosity between journalists and the military. The military frequently views press as offering only potential harm not benefit (Carruthers, 2000). The press, on the other hand, has a history of being critical of the military. For instance, U.  S. media and professional associations insist that the military must accommodate the press in wartime situations, for three good reasons which include: the press has always been present when troops have been involved; the public has a fundamental right to know; and restrictions put violate the First Amendment. Yet on some ground between the military operational requirement for information to be made available only on a basis of needing to know, and the right of the citizens of a democracy to know about what their military is doing, lies a middle ground (Dandeker, 1995). Generally, soldiers understand fighting and journalists understand communicating, yet none of them knows that the political impact of combat depends on how the fighting is communicated. Hence both sides need one another. Key civilian and military leaders have now embraced the fact that successful inclusion of the press to ensure adequate coverage is not an optional luxury, but rather is a necessity in todays information age and the expectations of the citizens. The benefits gained from the news media coverage of military operations outweigh the drawbacks, and therefore press coverage should be permitted. There is no set solution appropriate for every situation, since every war is unique. But improvements in military planning, officer training, and press indoctrination will help solve some of the current problems in the military/media relationship. How media assist the conduct of military operations In todays technology-driven world, the media is a fourth dimension added to air, land, and sea and the operational commander must contend with this potent entity to be relevant. Moreover, the media is an accelerator of immense importance in todays world in respect to the operational factors of time, space, and force affecting the operational commander decision-making. The reason why the military should engage the media is probably best stated by General (Ret) Dennis J.  Reimer in a 1997 memorandum to his senior Army leaders. â€Å"Our success, as an institution, depends on the degree to which all senior leaders communicate clearly to the people. It is in fact part of your METL [Mission Essential Task List],† said Reimer. To begin with, the military has the need for improved defense related public relations. The media is an important force multiplier, and it must be harnessed to win the battle of the hearts and minds of the people and keep them fully abreast of developments at home and abroad. This will ensure that they are not misled by rumors, propaganda and dis-information; this could happen if they do not have access to a truthful and speedy account of the facts and the progress of events. Secondly, the media is important in projecting the operations to the remotest parts of the country and arousing nationalism and patriotic fervour in the nation. Thirdly, having a media team at each level of command down to the battalion level is of great help to project the activities of the armed forces through films and other means. The procedure evolved provide for regular operational briefings by the operational/intelligence staff at headquarters or by the concerned corps/divisional commanders. Fourthly, training selected service officers and men in media work by running suitable courses for them on a regular basis and also media personnel need to understand the organisation, role, ethos and fighting capabilities of the armed forces and the characteristics of its various units is most beneficial (that is , media-military interface). Fifthly, limiting journalists access to a war can also work against the military. Galloway pointed to the Persian Gulf War as an example. When the war was over you had no proof of the efficacy of your efforts and your soldiers efforts to take up on [Capitol] Hill at a very difficult time when troop cuts, budget cuts, drawbacks are all under way, he said. Despite the constant tension and sometimes opposing goals of the military and the media, the militarys primary role is to support and defend the Constitution of the nation, the First Amendment of which is freedom of speech and of the press. Finally, having media-military interface there is hope for prompt and timely information in an age when news is increasingly being transmitted and used instantly, with TV news being broadcast on the hour, every hour (Krishna, 2000). How media limit the conduct of military operations The longstanding conflict between the news medias need for access and the militarys need for secrecy has continued during the war on terrorism, journalists agree. If anything, the tension between th e two groups has gotten worse. For instance, during the war in Afghanistan, Pentagon senior spokesman Bryan Whitman said the military understands reporters concerns but that the top priority must be troop safety. Ensuring †¦ that what we do with the news media in the Pentagon or in the field doesnt do anything to jeopardize the success of the operation or endanger the personnel that are participating in the military operation †¦ has to be balanced all the time with †¦ how much reporting can be taking place at any given moment, he said. (Wilcox Jr, 2002) But author and former war correspondent Joe Galloway, whose book We Were Soldiers Once †¦ and Young documents the first major U. S. ground battle of the Vietnam War, said that Vietnam changed the mindset of the military because of the open and unrestricted reporting done by journalists. Most of the times, the military is willing to learn, the journalists are not; pointed out by Galloway as evidenced by the numerous invitations he has received from the military to speak about the subject. He has not received any invitations to speak to news organizations or journalism schools. The media is also believed by them reporting from the battlefield turn the people against the military and against the war. Galloway also adds that, while Vietnam remains a model for him in terms of military/media relations, U. S. led military operations in Grenada and Panama were disastrous in terms of the medias ability to cover those conflicts because of military restrictions. Also, keeping the media at a greater distance from combat operations than security requires would contribute to a bitterly adversarial military-media relationship. This, in turn, would likely hurt the war effort in the long run by inviting relentlessly negative coverage and fanning public distrust. Furthermore, the media are a fact of military operations and here to stay as well as being vital to all democratic governments seeking to discharge their duty to explain. Military control of information during war time is also a major contributing factor to propaganda, especially when the media go along with it without question. The military recognizes the values of media and information control very well. The military often manipulates the mainstream media, by restricting or managing what information is presented and hence what the public are told. For them it is paramount to control the media. This can involve all manner of activities, from organizing media sessions and daily press briefings, or through providing managed access to war zones, to even planting stories. Over time then, the way that the media covers conflicts degrades in quality, critique and objectiveness. As one military puts it,† Information is the currency of victory. † From a military’s perspective, information warfare is another front on which a battle must be fought. However, as well as needing to deceive adversaries, in order to maintain public support, information to their own public must no doubt be managed as well. That makes sense from a military perspective. Sometimes the public can be willing to sacrifice detailed knowledge. But that can also lead to unaccountability and when information that is presented has been managed, propaganda is often the result. Finally, the military have had to adapt since 1982 is the speed of reporting made possible by modern communications. Today, a reporter with a digital camera, a laptop and a satellite phone, all of which can fit in a day sack, can file stories minutes after events and even live if they have a bit more by way of equipment. Control is much more difficult if reporters dont need military’s help to file a story. Because they can act so quickly, and are expected to do so by their editors or newsrooms, military dont have the time to ponder at length our response to events, we must respond quickly whilst still, crucially, maintaining accuracy. For instance, this happened on TELIC 1 (Iraq) but, it was not a great success. Conclusion Throughout history, no matter the time or war, there has always been a conflict between the military and the media. The media’s right to a free press conflicts with the military’s concern for operational security. It serves no constructive purpose, however, to ignore this conflict nor does it serve a purpose by adding to it. Therefore, it is time for the military to accept the media as part of the battlefield of the 21st century, and to understand and prepare for the media as it does for other battlefield elements. Commanders should ensure that their troops receive not only the equipment, but also the training to survive in adverse battlefield environments. The point here is to point out that no matter whether the military likes or dislikes the media, the media will be a part of the battlefield environment just as the weather. As is the case with inclement weather, the better the commander plans and prepares his or her troops, as well as themselves for the media, the better they and their troops will do when faced with a reporter. If we are going to get this right, the military must not resort unnecessarily to secrecy or to lightly tarring independent journalists as disloyal. The media should not frivolously cry censorship. And each should work harder to understand the views and accommodate the needs of the other.

American Dream Essay Example for Free

American Dream Essay The idea of dreams is integral to the main protagonists throughout The Bell Jar and Death of a Salesman. These ideas stem from the concept known as the American Dream, which is the belief that with enough work anyone can be what they want to be. The American Dream can often be related to the term Manifest Destiny, which is the belief in Americas mission in the world and can often be related to expanding their control over land. There are different types of American Dreams in the texts. These include Material, academic, 19th Century (outdoors), 20th Century (business) and Happiness, which the authors use to give us an inside look into the characters. The concept of the American Dream is presented in Plaths The Bell Jar in a similar way to Millers Death of a Salesman, when Plath states, look at what can happen in this country suggesting that the American Dream is a predominant thought in the American minds. In contrast to Millers main character, Willy, that foolishly follows the American Dream, the main character of The Bell Jar, Esther, does not believe this to be true and fights against the current of mainstream ideas and belief that if you work hard enough you can achieve anything. This is represented in the character, Doreen who is successful for just being beautiful, showing the shallowness of society. The American Dream is shown in Millers Death of a Salesman through characters such as Ben. Ben is the exemplary man with the American Dream; Miller writes that he walked out into the jungle and that when he came out he was rich. This belief that the American Dream can happen to anybody eventually drives his brother Willy to the tragic heroism of his suicide. This is a very depressing view and one that a lot of people can relate to, that the concept of the American Dream has a base of lies, deceit and luck such as Ben who ended up in Africa which then later made him rich. Although they both have differing attitudes toward the American Dream they both seek to achieve their own goals in a different manner. Willy is much more of a protagonist; he talks about being successful and how he will take action in the morning. On the other hand Esther is more pro-active in the pursuit of her dream as she is very academically successful and has never answered one test question wrong. Both of these approaches to seeking their dreams give us an insight into how the characters should have followed their dream and where their mistakes were, such as with Willy who often reminisces that he should have gone with Ben to the mines. Willy is so disillusioned that he will do anything in order to help Biff and Happy to achieve their dreams, which is the main factor in Willys suicide. We also get a sense of selfishness from this act of disillusionment as Willy seems to use his sons as an excuse for him to commit this act he has been clinging onto the American Dream so tightly that it became a veil over his eyes that left him blind to see he has the wrong dreams. Plath often uses the happiness dream in conjunction with the academic and material dreams to contrast with each other and to explore what the American Dream is and how to achieve it. We see this when Esther fed her clothes into the night wind which is Plath showing the reader that in order for Esther to achieve her happiness dream she does not need material objects. Plath uses techniques such as interior monologues to give us the deep feeling of failure residing in Esther and this gives us the impression that we should follow our own dream, instead of following a fake dream. While in contrast Miller uses the 19th and 20th century dreams in order to explore what the American Dream really is and how to achieve it. We can see this when Biff asks, Why am I trying to become what I dont want to be and states he desires to be outdoors with his shirt off for him to build a future. Biff represents freedom from the shackles of society, often breaking the convention, such as committing crimes in order to rebel. These explorations of the American Dream are very different in the way they are presented but both lead to the same conclusion, which is that you need to do more than strive and talk about your dreams, but act upon them, which both characters try, but evidently fail. Both writers look to expose the myth of the American Dream and the harsh reality within the characters of the respective texts. This idea is shown predominantly through the main characters, Willy and Esther, who are complete opposites in this view. Miller portrays Willy as the average low-middle class American who only has the hope of the dream to cling to and keep him going, this is why Willy doesnt understand the true meaning of the American Dream, as he himself has fallen into the cast to what he thinks society wants him to be. This is evident when he exaggerates; it is his way of following the American dream. He talks about how popular he is and how his funeral will be massive, whereas in reality he is unknown. His dream is to be rich and famous and to an extent he fools himself into believing this, such as when he talks about how he sold five hundred in Providence but then realises that he only sold two hundred gross on the whole trip. This gives us a sense of tragedy, that no matter how hard he tries to provide for his family, he is destined to fail, which Miller hints at with the attempted suicide with the rubber tube. However, Plath portrays Esther as a bright young women, who has the opportunity of living the American Dream but she can see through the illusion of what society thinks she should be. When she has her photo taken, she has to hold a fake rose and the rose doesnt represent her as a person or what she aspires to be, which is the point that Plath explores with regards to the American Dream in The Bell Jar. Plath and Miller use very different techniques to represent the American Dream. This is due to the texts being of different styles; one is a novel and the other a play. That said they do share some similarities, such as non-linear narratives to give us an insight into the key themes. The techniques used give different insights into the individual thoughts of the American Dream. One technique used by Plath is the interior monologue, which gives us the intimate thoughts of Esther and what she thinks of the world around her. Plath uses this technique to show her thoughts about the American Dream, as though they are her own thoughts represented in Esther. This gives us a very powerful opinion on the American Dream, as it is an opinion that is close to what we may also think from reading the novel. However Miller uses the flash-back technique in order to show where the idea of the American Dream originates and Willy and Esther perceive it this way. This form of stream-of-consciousness gives us a clear-cut view into what the character perceives and can often help us to understand of why the characters act as they do. One way that both authors explore the concept of the American Dream is by how the characters can achieve their individual dreams; this often leads to pressure to pursue the wrong dream. This is present in a lot of the characters in both texts such as Biff, who is the only realistic one in the Loman family. He realises his boundaries and abilities but in spite of this he still attempts to make a businessman out of himself though it is not what he wants, which he shows when he says, Why am I trying to become what I dont want to be. He also informs us that Willy has all the wrong dreams. This idea of becoming a successful businessman is a carbon copy of Willys dreams, pressed onto Biff. Though Biff, unlike Willy, doesnt procrastinate, everything for Willy is done in the morning and this is the main reason why he is unsuccessful, he talks instead of taking action as we are shown when Charley says that Bernards gonna do it instead of saying it, which Willy seems to admire. On the other hand Esther is the opposite of Willy; she is academically successful, more popular and has the chance to grasp the American Dream. Esther says I was supposed to be having the time of my life but the only problem with Esthers dream is that society wants her to be something else and this pressure is one of the reasons for her latter depression, when she was meant to be happy. When Plath uses the stream-of-consciousness technique we see that Esthers thoughts about the American Dream seem to deteriorate as her mental stability does, not even noticing when she could have potentially had a dream life in the fashion industry saying its somebody else in the magazine photo. Another character that Miller shows is following the wrong dream is Happy. He follows what Willy thinks he should be and he is always looking for his father to notice him, such as when he comments on how he is losing weight. This is an example of following the wrong dream. Happy has fallen prey to trying to make someone else happy by living their dream instead of following his own ambitions, which is the point that Miller explores. Miller has deliberately set up the brothers to have contrasts as we can see within the dreams they possess. Miller also explores the idea that the American Dream is possible if you try; this is in the case of Bernard. Bernard, like Ben, is the prime example of the American Dream coming true. Although he isnt as popular as Biff or Happy, he manages to be an academic and now presents cases in the supreme court, which genuinely shocks Willy as he recognises that Bernards dream has come true. For Willy there is also an air of envy that Bernard has followed the right dream. We see how Willy blindly follows the American Dream and that he doesnt truly understand what it is, he thinks that a personally attractive man will be able to be successful in the world of business. Willys understanding of the American Dream is limited as he believes that superficial qualities such as being liked is all a man needs whereas we are shown that it is hard work and risks that allow men to live the dream, such as Bernard who he often ridiculed for being an anaemic. Another point that shows us Willys little understanding of the American Dream is the metaphor its dark there, but full of diamonds. This metaphor means that through the hardship there will be a reward and is the main notion that drives Willy but it often appears in the form of Ben who reminds him. Ben gives the impression to Willy that he can do it, but also shows us Willys loosening grip to distinguish from reality and dream. The pressure to be something else or something great can have a massive strain on ones being and we can see this through the various suicide attempts by both Willy, with the rubber tube, and Esther with her trying to hang herself. In conclusion, I believe that each text explores the concept of the American Dream in very independent ways that express the opinions of the authors. Miller presents to us ideas such as to achieve the dream you have to be disillusioned which we see in the main protagonist, Willy. The combinations of techniques that Miller uses gives us the impression that nothing good can come out of the American Dream, as if almost hopeless to even have a dream. On the other hand, Plath uses the ideas of isolation being the problem, which we see in Esthers case. Plath uses the ideas of isolation coupled with depression to show the bleakness of striving to achieve a dream, which is a belief that Plath shares. This idea of isolation resonates in both main protagonists and leads back to the notion of society being the problem. Both characters dont fit in with society and are both under strain to be something they do not want to be. This gives us the sense that they are born into the wrong society and this I believe is the point that both authors try to explore, that there is nothing wrong with the characters themselves but it is the world around them that is flawed and through various narrative and stage techniques the authors convey this conclusion successfully. Bibliography Plath. S The Bell Jar Faber (1966) Miller. A Death of a Salesman Heinemann (1949) Dan Clarke

Substitution reaction

Substitution reaction Introduction Substitution reaction of chemistry substitution reaction are also called displacement reactions .These are the reactions in which an atom or a group of atoms attached to a carbon atom in a molecule is replaced by some other atom or group of atoms without any change in the structure of the remaining part of the molecule. The product formed is known as the substitution product. The new atom or group which enters the molecule is called the substituent. Some example of substitution reactions are: CHâ‚„+clâ‚‚ → CHâ‚Æ'cl+Hcl Methane Methyl chloride Here H-atom of CHâ‚„ is replaced by chloride atom. CHâ‚Æ'-CHâ‚‚Br+KOH (aq) → CHâ‚Æ'CHâ‚‚OH+KBr Ethyl bromide Ethyl alcohol Here Br atom of ethyl bromide is replaced by OH group. CHâ‚Æ' -CHâ‚‚ = CHâ‚‚ → ClCHâ‚‚ -CH=CHâ‚‚ + Hcl Propene Allyl chloride Here H-atom of CHâ‚Æ' group is replaced by cl-atom Types of substitution reaction Depending upon the nature of attacking reagent, substitution reactions can be classified as below: a) Electrophilic Substitution Reactions : These are the reactions in which an atom or group in a molecule is replaced by an electrophile. Such reactions are shown by aromatic compound. CHâ‚…+HONO₂→ CHâ‚…NOâ‚‚+H â‚‚0 CHâ‚…+ NO₂→CHâ‚… NOâ‚‚+H â‚‚0 (H â‚‚s0 â‚„) Here Nitronium ion (NOâ‚‚ ions )acts as an electrophile and the process is called nitration. Mechanism. Consider the chlorination of benzene in presence of halogen carrier(Feclâ‚Æ') Feclâ‚Æ'+cl-cl → Fecl₄⠁ »+cl(chloronium ion) Electrophiles are involved in electrophilic substitution reactions and particularly in electrophilic aromatic substitutions: Electrophilic reactions to other unsaturated compounds than arenes generally lead to electrophilic addition rather than substitution. B) Necleophilic Substitution Reactions:- These are the reaction sin which an atom or a group in a molecule is replaced by a nuclophile. Such reactions are shown by alkyl halides. Consider the action of aqueous KOH on methyl chloride. HO⠁ »+H -CHâ‚Æ' Cl→ Ho-cHâ‚Æ'OH+cl⠁ » A nucleophile (literally nucleus lover) is a molecule or ion capable of acting as a Lewis base (i.e., an electron pair donor). Nucleophiles can be described as electron-rich while their targets or substrates can be described as electron-deficient (they are Lewis acids, i.e., electron pair acceptors). In a nucleophilic substitution the nucleophile takes the place ofor substitutes forsome atom or group on the substrate (called the leaving group): Nu: + R:L → R:Nu+ + :L- nucleophile substrate product leaving group If the nucleophile is neutral (as shown above) the product will be charged since the leaving group takes both bonding electrons away with it. If the nucleophile is an anion then the product will be neutral: Nu: + R:L → R:Nu + :L- Stronger bases make better nucleophiles (e.g., OH- is a better nucleophile than H2O). Good substrates include cations, central atoms with incomplete octets or double bonds (like sp2 carbons) or carbons with partial positive charges. Halogens are generally more electronegative than carbon and so organohalogen compounds are usually subject to nucleophilic attack at the carbon attached to the halogen (which would be the positive end of a dipole). For example, 2-chloro-2-methylpropane (commonly known as t-butyl chloride) will undergo nucleophilic substitution with hydroxide ion: (CH3)3CCl + OH → (CH3)3COH + Cl This is a typical synthetic route for producing an alcohol from an alkyl halide. Nucleophilic substitution reactions have been studied for many years. It was noticed fairly early that while the overall reaction was similar in the vast majority of cases the kinetics of the process was not always the same. In some substitutions the concentration of the nucleophile had no effect on the rate. In others, the rate was directly proportional to the concentration of the nucleophile. This suggested that two different mechanisms must be at work. The factor which determines the mechanism employed is typically the nature of the substrate itself and NOT the particular nucleophile. Necleophilic substitution reactions are further classified as:- 1)Necleophilic substitution Biomolecular :- Such reaction sare shown by primary alkyl halides and involve a single step. The breaking of C-X bond and the making of C-OH bond takes place simultaneously. The neucleophile approaches the C-atom from the side opposite to that carrying the halogen. In such reactions, an inverted product is formed. The reaction involves the formation of a transition state. The reaction follows the rate law, Rate=k[Alkyl halide][OH]. As the slow rate determining step involves two molecule(Alkyl halide and alkali); therefore, the reaction is known as bimolecular substitution reaction. Most necleophilic substitutions, which involve the expulsion of an originally neutral substituent ,notably of halogen, from the aromatic ring,at temperature which are not particularly high,use the biomolecular mechanism SN2. This is established by their second order kinetics, which are documented by many records, (NOâ‚‚)â‚‚CHâ‚Æ'†¢Cl+OEt⠁ »Ã¢â€ â€™(NOâ‚‚)â‚‚CHâ‚Æ'†¢OEt+Cl⠁ » In substitution of this type,the rate of attack by different reagent on the same aromatic molecules follow the general order of nucleophilic strength towards carbon. This is the conclusion to which Bunnatt and Zahler come after having assembled data from many sources. The first mechanism is known as SN1 (substitution, nucleophilic, unimolecular) because only one molecule is involved in the first stepthe rate determining step. Reactions occurring by this mechanism should exhibit first-order kinetics, i.e., the rate law should have the form rate = k[substrate]1. Because the nucleophile is not involved until after the slow step its concentration will have no effect on the rate. The alternate mechanism is called SN2 (substitution, nucleophilic, bimolecular) because two molecules are involved in the rate determining (and only) step. Such reactions exhibit overall second-order kinetics. The rate is proportional to both the concentration of the substrate and the concentration of the nucleophile. Reactions like this will have a rate law in the form rate = k[substrate] [nucleophile] 2) Nucleophilic Substitution Unimolecular:- This mechanism is generally followed by tertiary alkyl halide. In the first step, tertiary alkyl halie breaks hydrolytically to form intermediate carbonium ion. The formation of carbonium ion is the slow rate determing step. In the second step, the nucleophile attacks tha carbonium ion to form an alcohol. Consider the action of aqueous KOH or tertiary Butyl bromide. CHâ‚Æ' CHâ‚Æ' CHâ‚Æ' ____ C-Br ⇄ CHâ‚Æ' C +Br⠁ » (Slow Step) CHâ‚Æ' CHâ‚Æ' CHâ‚Æ' CHâ‚Æ' CHâ‚Æ' ____ C + OH⠁ » ⇄ CHâ‚Æ' C +OH (Fast Step) CHâ‚Æ' CHâ‚Æ' (carbonium ion) Tert. butyl alcohol Or The best established eample of nucleophilic aromatic substitution by the unimolecular mechanism ,SN1,is the uncatalysed decomposition of diazoium ions,in hydroxylic solvent,to give phenols or phhenolic ethers,accomplished often byaryl halides or others such substitution products, if the necessary necleophilic anions are present in the solution: ArNâ‚‚+ → Ar+Nâ‚‚ (Slow) Ar+Hâ‚‚o →Ar†¢ OH+H (fast) Ar+ROH→Ar†¢OR+H (Fast) Ar +cl ⠁ »Ã¢â€ â€™ Ar†¢ Cl (Fast) These are SN1 mechanism . The alternate mechanism is called SN2 (substitution, nucleophilic, bimolecular) because two molecules are involved in the rate determining (and only) step. Such reactions exhibit overall second-order kinetics. The rate is proportional to both the concentration of the substrate and the concentration of the nucleophile. Reactions like this will have a rate law in the form rate = k[substrate] [nucleophile] 3) Free Radicals Subsitution Reactions[1.2.3] These are the reactions in which an atom or group of atoms in a molecule is replaced by a free radical. The replacement of H- atom by a halogen atom is an example of free radicals substitution.In the free radical substitution reaction, the attacking reagent is a free radicals. These reactions are carried either at high temperature or in the presence of ultra-violet light. In organic chemistry, a radical substitution reaction is a substitution reaction involving free radicals as a reactive intermediate The reaction always involves at least two steps, and possibly a third. In the first step called initiation (2,3) a free radical is created by photolysis. Homolysis can be brought about by heat or light but also by radical initiators such as organic peroxides or azo compounds. Light is used to create two free radicals from one diatomic species. The final step is called termination (6,7) in which the radical recombines with another radical species. If the reaction is not terminated, but instead the radical group(s) go on to react further, the steps where new radicals are formed and then react is collectively known as propagation (4,5) because a new radical is created available for secondary reactions. Mechanism. The mechanism of free radicals substitution involves three steps:- I) Initiation :- In this step, halogen molecule breaks homolyticallly to form free radicals. Consider the action of Brâ‚‚ on ethane in presence of sunlight. Br-Br Br II) Propagation step: The Br formed in the first step reacts with alkane molecule to form new free radicals which in turn reacts with bromine molecule and the chain react ion starts and so on. CHâ‚Æ'CHâ‚Æ'+Br →CHâ‚Æ' CHâ‚‚+HBr CHâ‚Æ' CHâ‚‚+Br -Br →CHâ‚Æ' CHâ‚‚Br+Br 3) Termination.: In this step, the free radicals combine and the reaction stops. Br + Br → Brâ‚‚ Similarly, consider action of Clâ‚‚ on propene. I) cl cl→ 2Cl II) CHâ‚‚=CH- CHâ‚Æ'+Cl→ CHâ‚‚=CH- CHâ‚‚+HCl CHâ‚‚=CH- CHâ‚‚+Cl-Cl→ CHâ‚‚=CH-CHâ‚‚Cl+Cl Substitution Reactions[1.2.3] Substitution Reactions. In an acid-base reaction such as CH3CO2H + NH3 → CH3CO2 + NH4+ the N acts as a nucleophile (Greek for â€Å"loving the nucleus), the H acts as an electrophile (â€Å"loves electrons†), and the O that accepts the pair of electrons acts as a leaving group. The acid-base reaction is the simplest model for a substitution reaction, which is a reaction in which a ÏÆ' bond between atom 1 and atom 2 is replaced by a ÏÆ' bond between atom 1 and atom 3. Substitution reactions are incredibly important in organic chemistry, and the most important of these involve substitutions at C. For example: This substitution reaction, discovered in 1849, involves the nucleophilic O making a new bond to the electrophilic C, and the bond between the electrophilic C and the leaving group I breaking. Any Brà ¸nsted base can also act as a nucleophile, and any nucleophile can also act as a Brà ¸nsted base, but some compounds are particularly good bases and particularly poor nucleophiles, whereas some are particularly poor bases and particularly good nucleophiles. Any Brà ¸nsted or Lewis acid can also act as an electrophile, but there are many electrophiles that are neither Brà ¸nsted nor Lewis acids (as in the example above). A haloalkane, e.g. CH3CH2Br, can in principle undergo either of two polar reactions when it encounters a lone pair nucleophile, e.g. MeO-. First, MeO- might replace Br- at the electrophilic C atom, forming a new C-O bond and giving an ether as the product. This is substitution, because the C-Br ÏÆ' bond is replaced with a C-O ÏÆ' bond. Second, MeO- might attack a H atom that is adjacent to the electrophilic C atom, giving MeOH, Br-, and an alkene as products. The electrons in the C-H bond move to form the Ï€ bond, and the electrons in the C-X bond leave with X-. This is elimination, because a new Ï€ bond is formed, and because the elements of the organic starting material are now divided between more tha n one product. Elimination requires that the substrate have a C-X bond and adjacent C-H bonds, while substitution requires only that the substrate have a C-X bond. Nucleophilic aromatic substitution reaction The name in the title in given to those substitution in whichnucleophilic reagent, such as Br⠁ », combine with aromatic carbon and aprecltyuviously present substituent such as †¢Cl,†¢NOâ‚‚, becomes expelled along with its bonding electrons With considerable difficultly even †¢H may be expelled with its bonding electrons i.e at H⠁ ». Biomolecular substitution reaction electron attracting substituent especially one conjugated with aromatic system such as nitro,carbonyl,syano aids the attack of the reagent and a 2-or 4-situated hetero atom ,as n pyridine ,acts in a similar way. Neuclophilic aromatic substtion can proceed by several,mechanism. The Unimolecular and Biomolecular mechanism can definitely be recognized and other mechanism some of which are understood,can be seen to exist. The unimolecular mechanism is limited to the replacement of those substituents which are sufficiently loosely bound to undergo spontaneous heterlysis in solution. The biomolecular mechanism is muc more general, doubtless because it make much less severe demands on thequality of the explled group,so that a hydrogen shift involved.

Maine Lobster: Soft-shell versus Hard shell :: Essays Papers

Maine Lobster: Soft-shell versus Hard shell A lobster must shed its shell in order to grow. It takes about five to seven years for a lobster to become a legal size harvestable adult. Soft-shell is the term used for a newly molted lobster. A soft-shell lobster has a shell with room for growth. Soft-shell lobsters are not as full of meat because their new shell is larger than the muscle inside the body. The part not filled with its body’s muscle tissue is filled with water. Soft-shell lobsters may look big on the outside, but they have a much lower meat yield on the inside. Most adult lobsters molt from June to September depending upon location and water temperatures. Hard-shell lobster is a lobster with an old shell whose body has completely filled its shell. A hard-shell lobster is a fully meated lobster which is mainly caught during the winter and spring months of the fishing season. During these months, lobsters are at their peak health and condition, and the meat yields are at their highest. Why do consumers prefer soft-shell lobsters to hard-shell lobsters? Many consumers prefer soft-shell lobsters over hard-shell lobsters because of several reasons. According to some people, meat from soft-shell lobsters is more tender than from hard-shell ones. They contend that the meat is sweeter and juicier than the hard-shell lobsters. In addition, some people prefer soft-shell lobsters because they do not need any tools to crack them apart. Moreover, some people prefer soft-shell lobsters because they are less expensive than hard-shell ones. If you are looking for cheap and abundant soft-shell lobsters, then the summer months are good because the weather does not keep lobstermen from fishing them. Why do consumers prefer hard-shell lobsters to soft-shell lobsters? Many consumers prefer hard-shell lobsters over soft-shell lobsters because of several reasons. Hard-shell lobster contains fifty percent more meat than the same size soft-shell lobster. Hard-shell meat is firmer, while soft-shell meat is softer and tends to have more water. Furthermore, hard-shell lobsters ship better than soft-shell lobsters because they are less likely to crack en route. If you are looking for hard-shell lobsters, the winter months are ideal for this, but prices are higher because it is more trying for lobstermen to be out in the elements.

Overview of the 60`s :: The Sixties American History Essays

Overview of the 60`s missing works cited Many social changes that were addressed in the 1960s are still the issues being confronted today. the '60s was a decade of social and political upheaval. in spite of all the turmoil, there were some positive results: the civil rights revolution, john f. Kennedy's bold vision of a new frontier, and the breathtaking advances in space, helped bring about progress and prosperity. however, much was negative: student and anti-war protest movements, political assassinations, and ghetto riots excited american people and resulted in lack of respect for authority and the law. The decade began under the shadow of the cold war with the soviet union, which was aggravated by the u-2 incident, the berlin wall, and the cuban missile crisis, along with the space race with the ussr. The decade ended under the shadow of the viet nam war, which deeply divided americans and their allies and damaged the country's self- confidence and sense of purpose. Even if you weren't alive during the '60s, you know what they meant when they said, "tune in, turn on, drop out." you know why the nation celebrates Martin luther king, jr.'s birthday. all of the social issues are reflected in today's society: the civil rights movement, the student movement, space exploration, the sexual revolution, the environment, medicine and health, and fun and fashion. The Civil Rights Movement The momentum of the previous decade's civil rights gains led by rev. Martin luther king, jr. carried over into the 1960s. but for most blacks, the tangible results were minimal. only a minuscule percentage of black children actually attended integrated schools, and in the south, "jim crow" practices barred blacks from jobs and public places. New groups and goals were formed, new tactics devised, to push forward for full equality. as often as not, white resistance resulted in violence. this violence spilled across tv screens nationwide. the average, neutral american, after seeing his/her tv screen, turned into a civil rights supporter. Black unity and white support continued to grow. in 1962, with the first large-scale public protest against racial discrimination, rev. Martin luther king, jr. Gave a dramatic and inspirational speech in washington, d.c. After a long march of thousands to the capital. the possibility of riot and bloodshed was always there, but the marchers took that chance so that they could accept the responsibilities of first class citizens. "the negro," King said in this speech, "lives on a lonely island of poverty in the midst of a vast ocean of material prosperity and finds himself an exile in his own land." King continued stolidly: "it would be