The enthalpy change of a reaction Essay Example for Free

The enthalpy change of a reaction Essay This is the equation for the reaction I intend to find the enthalpy change for. As this particular reaction is very difficult to measure the enthalpy change by carrying it out (the decomposition of CaCO3 needs a temperature of over 800i C), I must use another method and it uses Hess Law. Hess Law States: The enthalpy change for any chemical reaction is independent of the intermediate stages, provided the initial and final conditions are the same for each route. CaCO3 CaO + CO2 CaCl2 + CO2 + H2O. In simpler terms, the main point of Hess Law is that the total enthalpy change for the indirect route of a reaction is the same as the direct route, i. e. ?H1 = ? H2- ? H3. The diagram above represents a Hess Cycle or a Thermochemical Cycle. By knowing the enthalpy changes in two parts of the cycle, it is possible to calculate the third part and complete the cycle. This is how I am going to carry out my experiment. For my experiment I will: 1. ) React calcium carbonate with hydrochloric acid. 2. ) React calcium oxide with hydrochloric acid. In both of these reactions I will measure the enthalpy changes by recording the starting temperature and following the reaction, the end temperature. By following this procedure, I can calculate the change in temperature and consequently the enthalpy change. The apparatus I will need for these reactions includes: 2 x Polystyrene Cups 250ml Beaker Digital Thermometer 50ml Measuring Cylinder I decided to use a polystyrene cup so I could reduce heat loss polystyrene is an insulator, whereas if I had used glass heat loss would have been a huge influence on results. I am using a beaker so that when I need to move the reactants, I do not influence any temperature change just through my body heat. Also, the thought of the solution spilling was not a pleasant one, so in case of spillage, the beaker would catch it. The digital thermometer is much more accurate than a conventional thermometer because it reads down to 1 decimal point. Safety Apparatus: Safety glasses and lab-coat. The quantities of materials I have available: HCl (2. 0 mol dm-3) : As much as required CaCO3 : Between 2. 4g and 2. 6g CaO : As much as required. In order to determine the quantities I will need to use in the experiment, I must carry out a few simple calculations. Here is the equation for the first reaction I will carry out, involving CaCO3 and HCl. CaCO3 + 2HCl CaCl2 + H2O + CO2 This equation shows that 2 moles of HCl are needed for every 1 mole of CaCO3 to react. Using this information I can calculate the volume of HCl I will need in the reaction. I first need to find the number of moles of CaCO3 will be in the reaction: Number of Moles = Mass Relative Formula Mass No. of moles of CaCO3 2. 5g 100 0. 025 moles of CaCO3 Now I need to calculate the minimum amount of HCl I will need in the reaction. (Adding more would not affect the results because rate of reaction has no relevance to the experiment. All that is important in this reaction is that it is completed. ) Volume = Moles Concentration Volume of HCl 0. 05 (twice as many as CaCO3, as required) 2 0. 025 dm3 of HCl I now know that the quantities I require, in the first experiment, are as follows: CaCo3 About 2. 5g HCl 50cm3 (25cm3 is minimum any less will affect results). In the second reaction, involving Calcium Oxide and Hydrochloric acid, the equation is: CaO + 2HCl CaCl2 + H2O Again, like the first reaction, 2 moles of HCl are required to react with 1 mole of CaO. To keep things simple, I am going to use the same number of moles of CaO as CaCO3. Mass = Moles x Relative Formula Mass Mass of CaO needed = 0. 025 x 56 1. 4g Volume of HCl needed 0. 05 (twice as many as Ca0, as required) 2 0. 025 dm3 In order to carry out these experiments, the following directions should be carried out carefully. Method for reaction 1: CaCO3 and HCl. Add 2. 5g of CaCO3 to a polystyrene cup.   Place the polystyrene cup in a beaker.   Add 50cm3 of HCl to a 50ml measuring cylinder. Measure the temperature of the HCl.   Add the HCl to the CaCO3 and measure the end temperature. Once I have measured the end temperature I will compare it to the start temperature and calculate the temperature change. Method for reaction 2: CaO and HCl Add 1. 4g of CaO to a polystyrene cup. Place the polystyrene cup in a beaker.   Add 50cm3 of HCl to a 50ml measuring cylinder.   Measure the temperature of the HCl. Add the HCl to the CaO and measure the end temperature. Again, once I have measured the end temperature I will compare it to the start temperature and calculate the temperature change. Once the temperature changes have been calculated ? H needs to be found. Once all of the enthalpy changes have been calculated, follow the equation ? H1= ? H2- ? H3 Risk Assessment The substances which I am using are both fairly dangerous and have the potential to cause serious damage. Hydrochloric acid can cause burns and is irritating to the respiratory system. The molarity I am using is only irritant but this is still not pleasant. The only form of protection that is really needed while using HCl is to wear safety glasses. Calcium oxide causes burns and is irritating to the eyes, skin and respiratory system. Again, only eye protection is really needed with the use of this substance. By using my plan, I expect to get accurate and consistent results as I have calculated the exact amounts of substances needed and factors which will affect results, such as heat loss. Nothing in my experiment will give inaccurate or varied results as long as the method is followed strictly, i. e. correct and precise measurements of substances. The only way the experiment can be inaccurate therefore is through human error. Sources used in devising my plan:   Haz-Cards. Chemical Ideas, Second Edition Burton, Holman, Lazonby, Pilling, Waddington.   Class work notes Show preview only The above preview is unformatted text This student written piece of work is one of many that can be found in our GCSE Patterns of Behaviour section.

The Cuban Revolution Essay examples -- Cuban History, Fidel Castro,

After year of recruiting, training, plotting, Fidel was ready to launch his revolutionary offensive. â€Å"His rebel ‘army’ consisted of less than 200 men, and two women;† (Huberman 1960: 28) the group consisted of students or graduates, and nearly all of them were young people like himself and his brother, Raà ºl. Most of them were â€Å"politically active, articulate and impatient young men who had been drawn to the radical movements or to the ardently reformist Orthodox Party of Eduardo Chibas.† (Macgaffey 1962: 275) The rebels gathered outside Santiago, in the Fidel’s native Province of Oriente where they could launch an attack on Moncada Barracks, the army’s second largest military installation. (Huberman 1960: 28; Macgaffey 1962: 275) The attack was slated for July 26, 1953, at dawn, during the annual carnival celebration. (McCormick 1998: 67) â€Å"With the carnival in full sway, Castro expected the military to have its guard down.† (Leonard 1999: 9) At dawn of July 26, they divided into small groups to launch the assault, each group with specific objectives. The first intention was to â€Å"take by the surprise and capture the Fort Moncada, and take machine guns, tanks, armored trucks, up-to-date rifles and ammunition.† (Huberman 1960: 28) They could then seize radio stations, (Hampsey 2002: 95) and â€Å"They were to announce a revolution based on ‘Creole values,’ (Goldenberg 1965: 151) led by new men ... free of all obstacles with foreign nations and ... of appetites of politicians. They promised welfare and economic prosperity, social justice, respect for other nations, and respect for the constitution.† (Macgaffey 1962: 275, 276) â€Å"Such publicity was designed to call the people to revolt against the dictator, Batista,† (Hampsey 200... ... arrange a Military Junta.† (Goldenberg 1965: 163) However, before the plan could be put into operation, ‘the battle of Santa’ Clara took place, ending in a total fiasco for government troops.†(Goldenberg 1965: 163; Macgaffey 1962: 293) On the night of December 31, Batista and his collaborators fled to Dominica Republic. (Macgaffey 1962: 293) Immediately, Fidel called for general strike and subsequently, other major cities surrendered and Fidel and his rebels marched to Havana. (Goldenberg 1965: 163; Macgaffey 1962: 293) â€Å"Before the dawn on January 2, Fidel’s army marched into Santiago, and accepted unconditional surrender of Batista’s forces at Moncada.† (Goldenberg 1965: 163) The war was over and Fidel and his victorious army rode in triumph from one end of the island to the other and arrived in Havana on January 8. (Goldenberg 1965: 163; Macgaffey 1962: 293)

Mob Mentality

Mob mentality, or mob psychology, has been observed in numerous rock concerts and sports events in the United States, which often ends in riots and numerous people trampled to death. These events imply that there are certain influences exerted by a group that affect a person's behavior (Waddington & King, 2005). The effect of these observations is the conduct of many studies and theories in the field of social psychology.As early as 1895, Le Bon, who was writing about crowd psychology, published his work entitled, The Crowd: A Study of the Popular Mind. His work posits that people who form a large crowd lose their conscious personalities, and these are â€Å"replaced by a sinister uncivilised and potentially barbaric ‘collective mind (Waddington & King, 2005).’†The concept of mob psychology is rooted on the idea that the persons involved are burdened with an incapacity for self-control. Thus, these people who are susceptible of being part of the mob easily succumb to pressures, influences, and temptations (Feasibility and Admissibility of Mob Mentality Defenses, 1995).The perceived reason underlying mob mentality is classified into three complementary mechanisms. First among these is anonymity. A person who usually acts as a distinct person is prevented from behaving badly because his actins would be associated with himself alone. However, a person who loses his personality and becomes merely a part of large crowd becomes anonymous, making him feel liberated from personal responsibility from their actions (Waddington & King, 2005).Another mechanism involved in crowd disorder is suggestibility. Le Bon asserts that people in a group become â€Å"less resistant to the ‘hypnotic’ powers of suggestion.† Thus, the mob is compelled into engaging in abnormal and unsavory behavior. This mechanism suggested by Le Bon is built upon by Allport in 1924, who suggested that mob psychology involves â€Å"social facilitation† where by mutual stimulation causes the overriding of customary self-restraint exercised by people in normal circumstances (Waddington & King, 2005).  Finally, there is contagion. This mechanism refers to the fact that the â€Å"†high emotions spread contagiously† as if such effect is inevitable. This leads to the often-observed violent frenzy of mobs (Waddington & King, 2005).Mob mentality is a defense against criminal liability, and is based on psychological theory. In technical terms, it is referred to as Mob Violence Proclivity Syndrome. It belongs to other psychological defenses to criminal liability, such as child sexual abuse syndrome and rape trauma syndrome (Feasibility and Admissibility of Mob Mentality Defenses, 1995).The idea is that group criminal behavior is explained by the tendency of humans to get caught up in the excitement of situations and people such that they are unable to make meaningful, real, and rational decisions about their behavior (Feasibility a nd Admissibility of Mob Mentality Defenses, 1995).The legal community has observed the effects of an understanding of this human behavioral tendency on public policy, the law, and criminal liability. Whereas in the old times, crimes committed by a group had been made graver by the fact that several people participated in the act, nowadays, such fact is used to mitigate criminal liability of the offenders.Thus, the fact that people who merely followed the mob did not have the opportunity to make rational choices about their actions is enough to help them negate or avoid criminal responsibility for their acts (Feasibility and Admissibility of Mob Mentality Defenses, 1995). This particular effect of the psychological concept of mob mentality raises serious concerns on public policy and the law.ReferencesFeasibility and Admissibility of Mob Mentality Defenses. (1995). Harvard Law Review 108(5),   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   1111-1126.Waddington, D. & King, M. (2005). The Diso rderly Crowd: From Classical PsychologicalReductionism to Socio-Contextual Theory – The Impact on Public Order Policing   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Strategies. The Howard Journal 44 (5), 490–503

Animated Voice Images Of Tsunamis - 1031 Words

Animated voice: Footage of tsunamis. https://www.youtube.com/watch?v=vYy2h8IUV1U Yesterday afternoon, at approximately 14:46 JTS time, a massive 9.0 magnitude earthquake occurred just off the east coast of Japan, across from Sendai. The epicentre of the earthquake was at 38.322 °N 142.369 °E and caused a massive tsunami to form. Now we’ll go over to our very own reporter, Willow Jones, who will be explaining tsunamis for you. Willow: Live footage from studio. Hello, I’m Willow and I will be your reporter for tonight. Now, over 90% of tsunamis are caused by underwater earthquakes like this one. The other causes of tsunamis are underwater landslides, volcanos, and even meteorites! Earthquakes are caused by the movement of tectonic under†¦show more content†¦This goes on like a Mexican wave. When the energy reaches the surface, and has nowhere else to go, it translates outwards like a soundwave. Tsunamis can travel incredibly fast, as fast as 800km an hour! The longer it takes to reach land, the stronger the tsunami gets. Photo of the ring of fire. https://www.google.com.au/search?q=nuclear+disasterssafe=strictbiw=1536bih=690source=lnmstbm=ischsa=Xsqi=2ved=0ahUKEwj00teW1MzOAhUDl5QKHQp_DAAQ_AUIBigB#safe=stricttbm=ischq=ring+of+fireimgrc=De4mj2rYdEQ0_M%3A Early warning systems are installed at intervals on the ocean floor, especially around the ring of fire, where many earthquakes occur. Footage of tsunami. https://www.youtube.com/watch?v=S2ZOmMH4WHA#t=0.3316559 When a tsunami reaches the coastline of a country, the preliminary wave comes and acts like a sudden high tide. This wave then quickly disappears back into the ocean. This action provides an early warning system, letting people that in a few minutes the real tsunami wave is coming. When the real tsunami wave arrives, it will knock anything down that is in its path. Cars, people, and even buildings in the case of a large tsunami, will be pulled down. Although there are early warning systems, the message does not get out quick enough and many people are unaware that a tsunami is soon to come. Now we will go over to former nuclear reactor manager and scientist, Will Morgen, to explain

Archetypes In Charlotte Brontes Jane Eyre And Oedipus Rex

Archetype Essay An Archetype is a universal symbol with reoccurring representations in human culture. Archetypes are portrayed through symbols, themes, or characters that rise out of a universal pattern. The novel Jane Eyre and the play Oedipus Rex use the symbol of nature to give the reader a further understanding of the characters and the story. In Jane Eyre, Charlotte Bronte uses the archetypical symbol of nature in order to indirectly convey the feelings and future of Jane Eyre; similarly, this same archetype appears in Sophocles’ Oedipus Rex as well because nature expresses the appalling choices for which Oedipus has made. While these works use nature in the same way, both authors accomplish showing audiences the universal theme of†¦show more content†¦Bronte effectively uses the archetype of nature to furthermore portray Jane’s emotions and tell the audience how Jane truly feels in her current situation. Oedipus’ decisions are expressed through nat ure in the play, Oedipus Rex. When Oedipus becomes king and seeks the consultation of a priest, he is given the news that â€Å"the city is drowning† and â€Å"plague[s] attack† causing people to parish (Sophocles lines 23-27). The plague is a natural symbol of Oedipus’ sins for killing his father and wedding his mother. His sins are represented through the suffering of his town and people via the depleting natural resources. The town demands a solution to the crisis, and villagers bring their olive leaves to symbol their beacon of hope. The use of symbolism in this story plays an ironic role to reader. The reader learns about the wrong choices made by Oedipus through nature, but Oedipus doesn’t realize his choices, even though nature represents it, until the death of hid mother. The unknowing choice of marrying his mother indicates the natural connection between mother and child, and the marriage symbolizes the irony in his fate since his birth. The use of the Sphinx and its difficult riddle, which is consisted of animals (thus connecting to nature), symbolizes the wrong path for which Oedipus is heading, and when he gets the riddle correct, the Sphinx commits

Analysis Of Langston Hughes s Poetry Essay - 1813 Words

Langston Hughes is a well-known African-American writer who emerged from the Harlem Renaissance, which is also known as the turning point for African-American culture and literature. Because he is identified as such a prominent writer, he became honored as â€Å"Shakespeare of Harlem.† At an early age, Hughes wished to voice and represent his African-American culture through writing. Because Hughes had a range of styles and genres, he managed to write and publish sixteen volumes of poetry, ten collections of short fiction, two novels, two volumes of autobiography, nine books for children, and over a dozen works for the stage. His remarkable works are based on the rhythms of African-American music that combine elements from the old and new worlds of America. In his poetry, he expresses racial pride to African-American literature during enslavement, and he reveals the self-respect and inner strengths of blacks during the twentieth century. In his autobiography Hughes states that the folk stories he heard from his mentor and grandmother greatly influenced him as a writer. Hughes was also extremely passionate about the blues, and he was one of the few to take it as achievements and expressions of black culture. His desire for the blues acted as a stimulus to the productive reaction that makes his collections so influential. African-American music was central to Langston Hughes’s artistic poetry. Jazz was his most significant mark on black music, and he was only one of four writersShow MoreRelatedAnalysis Of Langston Hughes s Poetry977 Words   |  4 PagesLangston Hughes is widely renowned for his ability to represent the struggle of the African American community through his poetry during the time period around the Harlem Renaissance. As a world traveler and successful African American man, he was able to use his fame to enlighten the world, namely the white population, on the inequality and abuse of African American population in the United States. Despite his own battle with unhappiness and inequality (Royster, 344), Hughes was able to captureRead MoreAnalysis Of Langston Hughes s Poem I, Too978 Words   |  4 Pages Langston Hughes America, the ideals of freedom, equality, and opportunity traditionally held to be available to every American. This is what everyone was told, what the Declaration of Independence states. But, Langston Hughes a black American poet in the Harlem Renaissance period saw the truth. Being an African American in the United States during the early 1900’s was difficult. Many lived a life full of hardships; segregation, prejudice and economic hardships, viewed as second-class citizensRead MoreLangston Hughes The Weary Blues Analysis1256 Words   |  6 PagesOn Langston Hughes’s The Weary Blues Kevin Young, a graduate of Harvard University and one of the winners of the Guggenheim Fellowship, writes the historical perspective of Langston Hughes. He discusses the flowering of the African American literature and culture and how it is actually just the extension of the New Negro movement. From the Harlem Renaissance, Langston Hughes is able to represent â€Å"different things† for â€Å"different men.† The uprising of Hughes’s poems are the result of their hardshipsRead MoreAnalysis Of Mother To Son By Langston Hughes768 Words   |  4 Pagesï ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Ã¯ ¿ ½Grade:ï ¿ ½ Six    Standard:ï ¿ ½ #3:ï ¿ ½ Literary Response and Analysis    Key Concept:ï ¿ ½ Students respond to tone and meaning that are conveyed in poetry through word choice, figurative language, line length, punctuation, rhythm, alliteration, and rhyme.    Generalization:ï ¿ ½ Students respond to poetic language in Mother to Son by Langston Hughes.    Background:ï ¿ ½ Students have been working on a poetry unit and have been studying how the elements of poetry help the poet convey thoughts and meaning.ï ¿ ½ This lessonRead MoreAnalysis and Interpretation of I, Too Sing America by Langston Hughes1148 Words   |  5 PagesAmerica is considered to be very characteristic for radical poetry of Langston Hughes. The majority of literary critiques and historians refer to Hughes as one of the first American poets, who set the standards and examples how to challenge the post-World War I ethnic nationalism. His poetry contributed and shaped to some extent the politics of the Harlem Renaissance. In analysis of Black poetry Charles S. Johnson wrote that the new racial poetry of the Negro is the expression of something more than experimentationRead MoreJames Langston Hughes And Countee Cullen934 Words   |  4 Pages James Langston Hughes and Countee Cullen were prominent poets. These poets were at the time of the Harlem Renaissance during the 20th century. Hughes and Cullen wrote for others to understand the stories of African-Americans living in the United State. These men had differences in their writing, but one mutual objective. James Langston Hughes was born in Joplin, Missouri on February 1, 1902. Hughes began writing poetry when he lived in Lincoln, Illinois. The Weary Blues was his first book of poetryRead MorePoem Analysis : Langston Hughes Poem1258 Words   |  6 Pages Research Paper and Poem Analysis: Langston Hughes Poem Analysis: Langston Hughes’ poem â€Å"Mother To Son† is a twenty line poem that seems to be from the perspective of a prudent mother that is giving her son, and possibly the readers, some helpful and supportive advice, telling them that, no matter how many adversities they may face, they can not give up. I believe that this is the main theme of the poem, perseverance. â€Å"So, boy, don’t you turn back./ Don’t you set down on the steps./ ‘Cause youRead MoreAnalysis of Harlem by Langston Hughes602 Words   |  3 PagesAnalysis of Harlem by Langston Hughes Through the turbulent decades of the 1920s through the 1960s many of the black Americans went through difficult hardships and found comfort only in dreaming. Those especially who lived in the ghettos of Harlem would dream about a better place for them, their families, and their futures. Langston Hughes discusses dreams and what they could do in one of his poems, Harlem. Hughes poem begins: What happens to a dream deferred... Hughes is askingRead MoreThe Negro Speaks Of Rivers1548 Words   |  7 PagesLangston Hughes was an American poet, novelist, and playwright whose African-American themes names him a primary contributor to the Harlem Renaissance of the 1920s. After moving from several cities, Hughes and his mother finally settled in Cleveland, Ohio. During this time, Hughes began to write poetry. One of his teachers introduced him to the poetry of Carl Sandburg and Walt Whitman, both whom Hughes would later cite as primary influences. By the time Hughes was enrolled at Columbia UniversityRead More‚Äà ºEvaluation of ‚Äà ²Critical Essay on ‚Äà ²Theme for English B‚Äà ´Ã¢â‚¬Å¡Ãƒâ€žÃƒ ´Ã¢â‚¬Å¡Ãƒâ€žÃƒ ¹1291 Words   |  6 PagesEnglish B’’† â€Å"Critical Essay on ‘Theme for English B’†, written by Chris Semansky, is just that: an analytical essay on Langston Hughes’ poem â€Å"Theme for English B†. The article is a dissection of the author’s insight on the subject matter. The paper provides a detailed assessment of the content of Langston Hughes’ work by providing the reader with perspective on Hughes’ possible thoughts about people and the way they view themselves as well as others and how it affects their own judgments about

Cute Is What We Aim For free essay sample

Cute is What We Aim For, the pop/alternative band from Buffalo, New York is a good band. That much was revealed in 2006 when the band released The Same Old Blood Rush With A New Touch. In Cutes sophomore release Rotation the band proved that they were far more than a good band, they proved that they were a growing, developing band. First of all, the content of the album is superior and shows a real maturing. No longer lamenting about that unobtainable crush, the band has matured to topics that reflect the fact that theyre no longer teenagers. The albums first single Practice Makes Perfect, speaks of the regrettable mistakes made in young adulthood. The nostalgic Hollywood is the woes of a young person growing up in todays society, and wondering back to those times of old that to those of us in our early to mid twenties, really do seem like the age of innocence. We will write a custom essay sample on Cute Is What We Aim For or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page The lyrics on this album are far superior to that of the last. As good of a band as Cute is What We Aim For really is, there are certain things unforgivable about the lyric shallow as a shower or but my bottom lip along with the top one too. In this album, listeners will be delighted to find that the lyrics hold a certain depth to them, that had not been achieved by this particular band before. A personal favorite as far as superior lyrics go, is the albums closer Time. The general feel of the album so to speak also shows a superior sense of creative development. From the sultry Navigate Me to the sweet and sentimental Safe Ride, Cute is What We Aim For proved to their listeners that they can pull off a variety of music, while keeping themselves unique, fun and the same old band that die hards had fallen in love with earlier. Cute is What We Aim For is currently on tour with Ace Enders, Danger Radio and Powerspace. Their website is http://www.cuteiswhatweaimfor.com