Determination of Heat of Solution Essay Example for Free

Determination of Heat of Solution Essay ABSTRACT Thermodynamic values can be determined using the Vant Hoff isochore method. This method entails the use of equilibrium systems to determine the change in enthalpy of the solution, which can b related to the change in internal energy of the solution. The vant Hoff isochore relates the equilibrium constant of a chemical reaction at one temperature to the equilibrium constant of the same reaction at a different temperature, allowing it to be worked out for all temperatures if it is known for one. The experiment used the solution of toluene and naphthalene to determine the change in enthalpy. The mole fractions and the tempterature of recrylstallizations were graphed and the slope was determined. From the slope the change in enthalpy was determined to be 3.45J. This implies that energy is absorbed by the system. INTRODUCTION Solutions are very common in nature and in the chemistry lab. They provide the environment in which many chemical reactions occur. Thus, in the chemistry classroom and lab, we are immensely interested in solutions, especially liquid solutions. Solutions are defined as homogeneous mixtures of pure substances in which no precipitation or settling occurs. We often think of solutions as liquids, but we can have solutions of solids (alloys), gases (air is a solution of nitrogen, oxygen, carbon dioxide, and a number of other gases), and a combination of states such as liquid and solid metals (amalgams) and liquids and gases (nitrogen in the blood, carbonated beverages). The ease of dissolution is dependent on two factors: (1) the change in disorder or randomness (entropy) of the system and (2) the change in the energy of the process (heat of solution). The process is generally favored when the degree of randomness increases and the energy of the system decreases (exothermic). When dissolut ion occur the entropy of the system increases. For example, the ions in crystals are highly ordered. Once dissolved, these same ions in solution are relatively disordered. When a polymer is dissolved in a solvent, the heat measured is a sum of a polymer-solvent interaction term and a term related to the structure that existed in the solid polymer relative to its amorphous liquid state. This latter contribution, termed the â€Å"residual† heat, can have an endothermic contribution due to the fusion of crystalline regions and an exothermic contribution due to the disruption of structure in noncrystalline amorphous regions. Toluene, formerly known as toluol, is a clear, water-insoluble liquid with the typical smell of paint thinners. Chemically it is a mono-substituted benzene derivative, i.e. one in which a single hydrogen atom from the benzene molecule has been replaced by a univalent group, in this case CH3. It is an aromatic hydrocarbon that is widely used as an industrial feedstock and as a solvent. Like other solvents, toluene is sometimes also used as an inhalant drug for its intoxicating properties; however, this can potentially cause sever e neurological harm. Figure 1: Structure of Toluene Naphthalene, also known as naphthalin, bicyclo[4.4.0]deca-1,3,5,7,9-pentene or antimite is a crystalline, aromatic, white, solid hydrocarbon with formula C10H8 and the structure of two fused benzene rings. It is best known as the traditional, primary ingredient of mothballs. It is volatile, forming a flammable vapor, and readily sublimes at room temperature, producing a characteristic odor that is detectable at concentrations as low as 0.08 ppm by mass. Figure 2: Structure of Naphthalene EXPERIMENTAL A. Compounds tested Naphthalene, Toluene B. Procedures An accurate quantity of 15 g of naphthalene was weighed and placed into a test tube. An accurately measured volume of 5mL of toluene was also added. The stopper, thermometer, and stirrer were fitted in the set-up. The test tube was warmed in a water bath until all the solute was dissolved. The solution was allowed to cool in air, and was stirred continuously until an appearance of a solid was observed. The temperature at which the solid was observed was also recorded. Warming the mixture until the entire solid was re-dissolved and allowing the solution to be cooled in air also did a second determination. Another 1mL of toluene was added and steps 3 to 5 were repeated. Another four more 1mL portions of toluene were also added. The mole fractions were determined and graphed with the temperature of recrystallization. From the graph, the slope was determined and from the value of the slope, the enthalpy change of the solution. RESULTS AND DISCUSSIONS The mole fraction of the naphthalene to the toluene was determined and the temperature at which is recrystallized is tabulated below: Table 1: Mole Fraction and temperature of recrystallization Mole fraction| Temp.| 0.45| 67| 0.41| 60| 0.37| 59| 0.34| 56| 0.31| 56| 0.29| 54| Besides calorimetric method of analysis, using the equilibrium system may also be utilized to determine thermodynamic values. This is dependent to the enthalpy change. The mole fraction also interferes with the equilibrium system. Changes in the mole fraction will cause the equilibrium system to shift from one form to another. The process is in isochore, denoting no change in volume. The volume of the naphthalene is not diminished in the process of the experiment. The change in enthalpy is determined by determining the slope of the graph between the inverse of the emperature and the mole fraction. Figure3: Graph of Mole fraction versus the inverse of the recrystallization temperature From the grpah above, there is an inverse relationship between the recrystallization temperature and the mole fraction of naphthalene. As the mole fraction of the naphthalene is decreased, the inverse of the temperature of crystallization is increased. From the slope of the graph, we are able to determine the enthalpy change of the solution. Using the formula: Figure 4: Equation for enthalpy change From the equation above the determined enthalpy change is 3.45 J. Since the enthalpy change is a positive value the transfer of energy is towards the system. REFERENCES [1] Rossotti and H. Rossotti, The Determination of Stability Constants, McGraw-Hill, 1961 [2] Atkins, Peter; De Paula, Julio (2006-03-10). Physical Chemistry (8th ed.). W.H. Freeman and Company. p. 212. [3] NonLinear vant hoff solubility. http://www.sciencedirect.com/science?_ob=ArticleURL_udi=B6T7W-479CM6F-3M_user=10_coverDate=01%2F31%2F1984_rdoc=1_fmt=high_orig=search_origin=search_sort=d_docanchor=view=c_searchStrId=1474224563_rerunOrigin=google_acct=C000050221_version=1_urlVersion=0_userid=10md5=bc9cac9220a53d018a21b381170d2732searchtype=a. taken September 28, 2010 [4] Vant Hoff Isochore. http://www.scenta.co.uk/tcaep/nonxml/science/equations/details/vant%20Hoff%20isochore.htm taken September 28, 2010.

The University Art Gallery Show :: Visual Arts Paintings Art

The University Art Gallery Show Its bright, It's brash it's stimulating. It's Art Express '06! This years show displayed at the University Art gallery, demonstrated the growing interest in contemporary issues and cultural awareness. The Show was set up in separate sections, with similar artworks placed around the same sections of space. There were two glass presentation boxes going along the centre on either side of the room, with three main walls, leading onto smaller walls, presenting the HSC selected works. The set up was cleverly done, as it was very easy to casually walk around and view all the works with out any trouble. As always publicized in each year's art express, it was impossible not to notice the extreme range of different media and forms of works the students used. Ranging from medias like a clothesline to neon lights to print making. You couldn't help but be thrown into the world of the giant splurges of creativity around you; it will make you want to run home and sort through your local tip or bring out the old brushes to whip out something exciting. The term 'Major work is no longer ' used but replaced by 'Body of work'. The difference being before the student only had to complete one work to complete their practical. Now students have to complete a number of works all interrelating between each other. One of the most outstanding body of works shown that I think boldly stood out from the pack was "Mon Inversion Fragmentee (My fragmented inversion)" by Cara Lee, from Kambala. This work explored the social representation of women. 300 black and white photos each depict a close up image of a fragment of the divided female body. The rigidity of each individually hung photo exemplifies the restriction of the female and the extent to which they're boxed by society and social conventions. The strengths of the works this year were that the individual works challenged your way of thought. These students are not afraid to share their opinions to the public. It's become a trend that the general public will find it harder to just view a work and simply decide whether it is aesthetically appealing to them or not, with out also stopping to question the world around them or within themselves. Mon Inversion Fragmentee, Scientific Research; Cell your soul Manipulate and Hidden

Gender culture and ethnicity

The understanding of the terms gender, ethnicity, and culture and their influence on the family is the core factor in this paper. These terms have diverse definitions though the understanding is basically the same. This is because the terms are applied differently in different social set-ups. Culture can refer to the common beliefs, values, symbols and meanings, passed on from one generation to another in time.Ethnicity would refer to a common ancestral linage, sense of belonging, and is a major factor in the determination of identity through which communities evolve and develop common value systems and. Gender, as a term has two components mainly role and identity it is the characteristics that society and individuals attach to males or females. Gender identity is the private sense of being masculine or feminine. While gender roles are the prescribed expectations of society towards men or women. Table of contents Abstract 2 Introduction 4Understanding of gender, culture, and ethnici ty 5 Family rituals, traditions, and transitions 7 Conclusion 9 Reference †¦10. Introduction The combined roles of gender, ethnicity, and culture have an important impact in any family set-up. While gender identity is a private perception of being masculine of feminine the expectations of society is what mainly determines an individual’s perception of the same (McGoldrick et al 1996). Although the roles of gender are dictated by the greater society transitions in families and exposure can bring a shift from the norm.While culture would refer to the common beliefs, values, symbols and meanings, passed on from one generation to another in time (Goldenburg & Goldenburg, 2000), this is always subject to change as value systems are dynamic and are influenced by outside factors such as education and to a large extent globalization and its effects on individuals. While ethnicity would refer to a common ancestral linage and sense of belonging (McGoldrick et al,1996), it does not change what changes is its influence in the individual’s interpersonal relationships as other factors come into play.These factors are mainly exposure and education. Understanding of gender, culture, and ethnicity A three-generation family genogram. Legend Examples of gender roles in my family of origin. The gender roles in my family of origin were not quite clearly spelt out. This is because as society in Chile would demand the men were the family bread winners, and they carried the family’s vision. However, we were brought up from a tender age by our mother almost single handedly. The reason being my father had an alcoholic problem which led into a troubled marriage ending in divorce.My mother had to work to bring us up. The preservation of family traditions is the prerogative of the man and this was done by our paternal grandfather. Now that he is quite old, family traditions are no longer adhered to unlike the case in the past. People of different race or ethnic o rientation, were not welcome in our family. The major reason being the older generation was not accommodating to them. The feeling among the family was the people of different race or ethnicity were second class citizens.The roles of men and women were not clear since in my family my father was absent and my mother performed the roles that society regarded as masculine such as working to raise the family. Women were normally expected to stay at home as housewives taking care of the children and day-day household chores. An outsider is any person who does not belong into our family ancestral blood-line or assimilated into the family by way of marriage. These were treated with suspicion and at times contempt. Whereas an insider is that person born into the blood-line or married into the family line, and were treated with respect.These messages have broadened my view of interpersonal relationships. Biases, prejudices, and stereotypes. Biases, prejudices, and stereotypes learnt: I came to look down upon domestic servants as a low class people. This is basically from the stereotyping in our society, since these jobs were mainly for the uneducated and were lowly paid. People of different color or ethnicity were seen as second class and were marginalized in every sphere of life including the job market. Education in our family was seen as the only means to getting acceptable standards of living. Family rituals, traditions, and transitionsRituals in my family. Saying prayers every day before dinner was a ritual our family grew up with. This occurred because my mother was a strong religious woman who instilled moral and religious values in us. She was a strong Catholic woman and prayers were the family cornerstone. Since my paternal grandparents are still alive and are the stronger side of our family, the entire family as well as the extended family needs to congregate at our grandparents’ home for holidays like Christmas. This will bring our father back into th e family as we spend time together and reflect on the events of our lives as a family in the past year.It will help all the family appreciate each other and provide room for change where necessary. In developing a ritual for a family one has to first understand the daily or calendar routine of the family. A family ritual assists the family to develop close bonding. Spending good quality time together especially at the dinner table is one ritual that would serve this purpose. At this time the family members would reflect on the events of the day and issues that arise can be discussed at this time. Dinner needs to be served at a time convenient to all members of the family.This will assist the family to grow as a close knit unit where each family member is responsible for the general well being of the family as a whole. A tradition in my family. As we grew up one tradition was to visit our paternal grandparents every holiday. We would spend time with them at the beach over the summer holidays for as long as two months. They were a loving couple and very close to their family. The time we would spend with them helped me as I grew to appreciate family bonding as I felt the love and warmth they gave to all of us. This affected me directly because I did not see the same love and affection between my own parents.My parents were divorced after a troubled marriage, since my father was an alcoholic. The time spent with our grandparents made me appreciate the institution of marriage as a life-long commitment. Transition in my family. One major transition in our family was my father’s alcoholic problem. Alcoholism destroyed our family structure in that my parents got divorced when we were young children and we were brought up by our mother almost single-handedly. In my country Chile, men were the bread winners and household heads while women were basically housewives. This was however not the case in our family. Our family was a woman-headed household.It was my mot her who instilled religious and moral values in us. She was the one who carried the family burden although our father would help us occasionally. A tradition in my family that needs to be changed. A tradition that needs to be changed in our family is that of employing maids, chauffeurs and all sorts of servants. As much as this helps in the growth of the national economy in terms of employment, at the family level it drains family resources and also encourages a dependency syndrome in the children. This is because they grow up seeing other people do things for them, and therefore lack a sense of responsibility.It does not help in molding children into responsible adults. This tradition needs to be changed and families should only employ a minimal number of servants leaving the children and young adults with some responsibilities to take care of. This would help our family in that the men would grow up dealing with their responsibilities as society demands and not leave their househo lds to be headed by their wives. The women will grow to be strong women like our mother being able to provide for their families even when the men neglect responsibilities.Conclusion In conclusion, the influence of gender, culture and ethnicity has greatly molded my family. Gender, culture and ethnicity need to be understood in a modern sense since they are the major sources of stereotyping. The influence of exposure and education is what has positively impacted on the families inter personal relationships. References Goldeburg, I. , Goldenburg, H. (2000). Family therapy 5th ed. Australia: Brooks/Cole McGoldrick, M. , Giordano, J. , & Pearce, J. (1996). Ethnicity and family therapy. New York. Guilford

Kenneth Branagh s Hamlet ( 1996 ) - 975 Words

Kenneth Branagh s Hamlet (1996) is the most complete retelling of William Shakespeare s Hamlet. In four hours, Branagh details the complicated relationships and mental anguish of the royalty of Denmark as they navigate the murder of the king of Denmark, notably Hamlet, the heir to the throne of Denmark. As Hamlet has been tackled by many actors and filmmakers over centuries, there is no one true way to perform Hamlet. Nor has Hamlet been approached such as Branagh has, creating a screenplay using the full text from both the Quartos and the First Folio. Therefore, Branagh has taken the liberty of fully fleshing out his film through advanced cinematography techniques and meticulous attention to details. Kenneth Branagh s Hamlet uses framing of shots and accompanying color schemes, detailed flashbacks, and an emotionally charged musical score to project Hamlet s internal conflicts onto his environment, creating a tangible representation for viewers. Hamlet is introduced with his iconic line in response to Claudius s introduction, â€Å"A little more than kin and less than kind† (Shakespeare, 14). As shown in the image above, Hamlet stands alone, framed by the curtain to the left and the wall lined with candlesticks to the right. This long shot clearly places Hamlet as the center of focus. This is done primarily through contrast. Most of the surrounding image is dark, and the only area illuminated at this time is around Hamlet. Contrast is taken one step further by clothingShow MoreRelatedGibson and Branagh in the Movie Versions of Shakespeare’s Hamlet 1228 Words   |  5 PagesHamlet is one of Shakespeare’s most well-known and most frequently performed plays. Many people have enjoyed reading and watching hamlet, both on stage and theatrically, Tragedy of Prince Hamlet revolves around the idea of tragedy, incest and revenge. However, Hamlet uses puns to lighten the mood. Franco Zeffirelli’s version of Hamlet was released in 1990, with Mel Gibson playing as hamlet, Glenn Close as Gertrude, Alan Bates as Claudius, and lastly Helena Bonham Carter as Ophelia.Read MoreHamlet Essay1901 Words   |  8 PagesGhost in Kenneth Brannagh’s Hamlet: A Masterpiece William Shakespeare’s Hamlet is a tragedy known for its drama and portrayal of its characters. For many decades, the play has undergone different interpretations as well as criticisms. An important factor of the play that has gone through this criticism is the character of the ghost who appears to be Hamlet’s dead father. After the first encounter between Hamlet and his â€Å"father†, it seems apparent that the ghost is in fact Old Hamlet, returningRead MorePortrayal Of Ophelia Throughout The Two Film Versions Of Hamlet925 Words   |  4 Pages Simran Jandu Mr. Crawford English 40S November 11, 2016 Portrayal of Ophelia in the two film versions of Hamlet Hamlet is an acknowledging Shakespearean play that was later filmed in 1990 by Franco Zeffirelli and in 1996 by Kenneth Branagh. Both these directors interpret the play differently adding unique twists and turns of their own to help focus on one thing than the other. In their contrasting films, these two directors depict the character of Ophelia very differently. Through Zeffirelli’sRead MoreBetrayal In Shakespeares Hamlet1395 Words   |  6 Pagescan trust for anything. Right? However in the William Shakespeare s tragedy, Hamlet, he exposes the few wicked relationships within different character s transactions. This essay expresses how without support or a backbone in a relationship can be detriment to any self growth for the future. Shakespeare devotes his scripting to narrate the hideous ironic death of each main character from the act of betrayal. Some traits that Hamlet possesses which people inaccurately diagnosed him with insanity.Read MoreInside A Or Inside Looking O ut Essay1721 Words   |  7 PagesThat is thy question. Who is prince Hamlet? What is he like? Hamlet is one of the most dynamic, if not the most dynamic character, in the play Hamlet. He happens to be on of the most eccentric beings that Shakespeare put in his works. Throughout the play, he was someone who endured a lot of adversity and did not even sweat a drop from his brow. He stayed cool and displayed his best features. His honesty is admirable also his heart that is like that of a lion. Hamlet is a person who is very blunt and