Mass Relationships in Chemical Reactions Essay Example for Free

Mass Relationships in Chemical Reactions Essay Aim The aim of this experiment is to show that a reaction doesnt have always 100% yield by reacting NaHCO3 and HCl and determining the amount of the products to calculate actual yield. Introduction A chemical reaction will be quantitative if one of the reactants is completely consumed. In this experiment sodium bicarbonate and hydrochloric acid start a reaction. The formula of this reaction is below. NaHCO3 + HCl NaCl + H2O + CO2 Observations In this experiment, sodium bicarbonate is put in an evaporating dish and some amount of HCl is added in the dish and the reaction started. Bubbles are formed and CO2 gas is produced and the reaction started to make sound. There was also water vapor formed. White NaHCO3 started to turn into a colorless liquid after adding HCl. As the reaction takes place water is started to form. NaCl was dissolved in water, so salty water is heated to obtain NaCl. As the liquid is heated it turned into a yellowish color for a few seconds. Then it started bubbling and water vapor is formed. Raw Data: Trial # Mass of Dish+NaHCO3+Lid +- 0.1 (g) Mass of NaCl+Water+Dish+Lid +- 0.1 (g) Mass of NaCl+Dish+Lid +- 0.1 (g) 1 64.14 g. 72.16 g. 63.28 g. 2 65.14 g. 72.95 g. 63.91g. Mass of Evaporating Dish + Lid: 62.14 +-0.1 g Processed Data: Trial #1 64.14 62.14 = 2 g NaHCO3 72.16 62.14 = 10.02 g NaCl + H2O 63.28 62.14 = 1.14 g NaCl Trial # 2 65.14 62.14 = 3 g NaHCO3 72.95 62.14 = 10.81 g NaCl + H2O 63.91 62.14 = 2.07 g NaCl Trial # Mass of NaHCO3 (g) Mass of NaCl + H2O (g) Mass of NaCl (g) 1 2 g 10.02 g 1.14 g 2 3 g 10.81 g 1.77g Calculations Na: 14.01 g/mol, H: 1.01 g/mol, Cl: 35.45 g/mol, O: 16 g/mol, C: 12.01 g/mol NaCl= 49.46 g/mol H2O= 18.02 g/mol NaHCO3: 75.03 g/mol Mole number of NaHCO3 = mole number of NaCl Trial #1 2 / 73.03 = 0.0274 mol NaHCO3 1.14 / 49.46 = 0.0230 mol NaCl Theoretical Yield: 0.0274 mol NaCl Percent Yield: 0.0230 / 0.0274 = 0.8394 x 100 = 83.94% Trial #2 3 / 73.03 = 0.0411 mol NaHCO3 1.77 / 49.46 = 0.0358 mol NaCl Theoretical Yield: 0.0411 mol NaCl Percent Yield: 0.0358 / 0.0411 = 0.8710 x 100 = 87.10% Conclusion The results are 83.94% for trial #1 and 87.10% for trial #2. Trial #2 is more accurate. The accepted value is 100%. The percentage errors are 16.06% for trial #1 and 12.90% for trial #2. The uncertainties are too small to calculate on the results. Random errors presented in this experiment. All the errors were done by human beings. There werent any errors due to a flaw of a machine or the procedure. Evaluation When salty water is heated on the first trial, the substance started to spill around, because the substance is heated with high amount of heat and faster than it should be. As a result, some of the NaCl which stuck on the lid and spilled around was lost, so the result of the first experiment is not accurate. Other reasons that changed the results may be all NaHCO3 may not be dissolved. Too much HCl may be added on the dish. There may be still water molecules left on the salt after heating. To get more accurate results, the experiment should be done more slowly than this experiment. Especially the heating process should be done slowly, so the evaporation can be observed more carefully.

Causes of the Easter Uprising Essays -- Essays Papers

Causes of the Easter Uprising In the mid 1800s the course of Irish history was changed forever. The Irish were devastated by The Great Potato Famine of the mid to late 1800s. Population declined from over eight million people in 1840 to under 4.5 million in 1900 due to death and immigration (O’Rourke 2). The poorer Irish people, unlike many British citizens, relied almost entirely on agriculture. The Irish immigration not only affected Ireland and Britain, but its affects were felt over much of the world, including the United States. The famine had a significant effect on the future of Irish history including Home Rule legislation, The Easter Uprising of 1916, and the eventual creation of an Irish free state in the early twentieth century. In the early 1900s, Irish nationalists were fed up with the British rule that had dominated Ireland since its existence. The Irish in this situation closely resemble the American Colonists prior to the American Revolution. The Irish felt as if the British did not represent them well and they wanted to run their own country and govern themselves. There were many small rebellions and confrontations between some Irish citizens and the British army all throughout Ireland’s history with the purpose of lowering the morale of British troops that occupied Ireland, or in rebellion to specific actions by the British. However, there never was any organized uprising with a goal of completely eliminating the British like the Easter Uprising in 1916. Irish nationalists planned to take Dublin and all of Ireland by force and rid themselves of the British. On the morning of Monday April 24, 1916, the day after Easter, a force between 1,000 and 1,500 men and women began a rebellion that they hope... ...e uprising had on the young Irish nationalists. Both Connolly and Pearse were strong leaders that were well respected and influenced many of the men that they worked with in the uprising. Though Eamon de Valera was an extremely powerful speaker and tremendous leader, he still received all of his early guidance from the leaders of the uprising. The Easter Uprising is one event that can be attributed to Ireland starting down the path of independence and self-government. The efforts and deaths of those involved seemed to show the defeat of the rebellion, but the ensuing support for the revolution that followed showed that the uprising was an overwhelming success. Today those men and women who gave their lives in the Easter Uprising as well as all the other efforts and rebellions that led to the formation of the Irish Free State are regarded to as national heroes.

Body Image in Brazil and Usa

Body Image in Brazil and USA Four thousand years ago the last of the mammoths were roaming the earth before extinction, anesthesia was still 3800 years away from being discovered, and tools were still being made out of stone. What else was happening that long ago? Humans were performing the first known cases of reconstructive and cosmetic surgeries, documenting back to skin grafts in ancient India. Between the first documented procedures and the early 1800's not a lot progressed aside from the basic tools being used. In 1827, Dr.John Peter Mettaue performed the first cleft palate operation using tools of his own design kicking off the modern plastic surgery advancements. Using the advancements in reconstructive surgeries became increasingly popular during World War I as it was used to save many soldiers' lives throughout the world. In the late 1940’s, following the second World War, the focus of plastic surgery began to shift from medical procedures to save lives in the milita ry to a more public and socialized practice. A boom in the 1960's spread rapidly after the introduction of silicone implants by Dr. Thomas Cronin.Sports Illustrated Magazine issued its first swim suit edition in 1964 featuring a five page spread of bikini clad perfect model bodies that the public was pressured to imitate. Despite the American involvement in Vietnam during the late 60's the trend continued to increase into the 70's when plastic surgery hit an all-time high due to the public discovery of its uses on all parts of the body. Over the decades, countries throughout the world including Brazil and The United States have adopted plastic surgery as an active part of their cultures despite monetary and health costs all because of media and social pressures.The United States and Brazil rank first and second in the world of most plastic surgery procedures, respectively. According to Dr. Daniela Dorneles de Andrade, a psychological research associate at the University of Vienna, t he United States alone underwent 30. 1 million cosmetic surgeries in the year 2009, enough cosmetic surgeries for one in every ten Americans to have undergone some sort of altering procedure. The United States is the only country to top the next leading country, Brazil, which reported 13. 7 million procedures.Based on its population, that amounts to one in every fifteen Brazilians volunteering for of these surgeries in the same year (Dorneles 75). The American Society of Plastic Surgeons reports the average cost of plastic surgery procedures being at five thousand dollars in the United States incurring a total revenue topping one hundred and fifty billion dollars a year from voluntary surgeries alone. The figure dwarfs Brazil's reported income from the same procedures however, topping just over fifty million dollars (ASPS).Professor Alexander Edmonds, of Macquarie University, reports that the lack of funds reported by Brazil is due to a philosophy that â€Å"the poor have a right t o be beautiful† (Edmonds, â€Å"Poor† 363). The thought that everyone has a right to undergo plastic surgery, even if they cannot afford it, has been adopted by many Brazilian surgeons. Brazilian surgeons have started clinics that are being funded by federal and municipal budgets to provide procedures to everyone regardless of economic ability (Edmonds, â€Å"Poor† 365). Such acts are not only costing people in American and Brazilian cultures money but also costing them their health.Both psychological and physical health are being put into jeopardy by the procedures themselves and also by the desire to have them done (Edmonds, â€Å"Learning† 470). Health care related spending has nearly tripled in the past three centuries, seventy-eight percent of which linked to complications of cosmetic surgery. Whether it is leaking silicone implants or infections, the surgeries that people are seeking out to make themselves more perfect on the outside are in fact lead ing to more problems than with what they started with (Dorneles 77).Why are people of the world putting themselves through these extensive procedures? University of Amsterdam professor, Alexander Edmonds, says it amounts to nothing more than acceptance and expectance. The pressure to appear as perfect as possible on the outside is largely placed upon the women in both Brazilian and American culture. Such pressure is put upon women, young women most heavily, by media and social groups alike. Social groups are driven by what they see in magazine or on television ads. Media thrives on what social groups are deeming appropriate amongst themselves.The vicious cycle of perfection that American teens and young adults face every day is the same pressure that is seen in Brazil. More and more young people are turning to evasive procedures to correct themselves every day. In 2010 the second most popular gift given to high school graduates in America, trailing closely behind a new car, was that of breast augmentations (Kreimer). These gifts are giving by family members or people who care about the young person's life and they feel that their child will thrive better in life if they help them achieve a better body.This thinking is passed on from generation to the next and is rapidly increasing. One teen who received such a gift was quoted saying, â€Å"My mother, grandmother, two aunts, and stepmother have implants, so if my mom is willing to pay for it, why not? † (qtd in Kriemer). The pressure to appear a certain way is becoming even more important to people of the world with no consideration for the health and financial implications. It is becoming accepted by cultures around the globe as a normal practice.If the past is any indication for the future this issue will become an uncontrollable epidemic. Something needs to be done about how media portrays people but are the thoughts of societies and morals of cultures being influenced by the media or is the media bei ng conformed by the cultures and societies serves? Works Cited ASPS (American Society of Plastic Surgeons). The Plastic Surgery Foundation, 2012. Web. 23 Oct. 2012. Dorneles de Andrade, Daniela. â€Å"On Norms and Bodies: Findings from Field Research on Cosmetic Surgery in Rio de Janeiro, Brazil. Reproductive Health Matters 18. 35 (2010) : 74-83. Print. Edmonds, Alexander. â€Å"Learning to Love Yourself: Esthetics, Health, and Therapeutics in Brazilian Plastic Surgery. † Routledge Journals 74. 4 (2009) : 465-489. Print. Edmonds, Alexander. â€Å"’The Poor Have the Right To Be Beautiful’: Cosmetic Surgery in Neoliberal Brazil. † Journal of the Royal Anthropological Institute 13. 1 (2007) : 363-381. Print. Kreimer, Susan. â€Å"Teens Getting Breast Implants for Graduation. † Womensenews. Women’s eNews Inc. , 6 June. 2004. Web. 26 Oct 2012.

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