Preparing Salts- IB Lab Essay Example for Free

Preparing Salts- IB Lab Essay Calcium chloride (CaCl2) has been manufactured for over 100 years. The salt is used in a variety of industrial and consumer products, and is supplied as flakes, pebbles, pellets, powders and solutions with varying concentrations. Calcium chloride dissociates easily in water to form Ca and Cl ions. Calcium is essential for the formation of skeletons, neural transmission, and muscle contraction, coagulation of the blood, and algae and higher plant growth. Chloride ions are also required for normal cellular operations in animals and humans, and serve as a micronutrient for plants, playing important roles in photosynthesis and osmoregulation. Calcium chloride is considered to be practically non-toxic to aquatic organisms and bioaccumulation is unlikely. Calcium chloride does not burn and is not flammable. Calcium chloride is corrosive to some metals. Calcium chloride is completely soluble in water. Because calcium chloride is hygroscopic, it should be stored in a dry place and be protected from atmospheric moisture. Heat is produced when calcium chloride is dissolved in water and spattering and boiling can occur. (Calcium Chloride SIDS Initial Assessment Profile, 4, 12-14) Salts are prepared by five methods. A metal can combine directly with a nonmetal to form a salt. A metal can react with acid to form a salt and release hydrogen gas. A base can react with an acid to form a salt and water. An acid can react with a carbonate and form a salt, carbon dioxide and water. And finally two salts can react to form two other salts. AIM (PURPOSE) Our aim was to create 0,124 grams of calcium chloride. In order to prepare the salt, we used a base and an acid. The reason why we chose this method was first, we had the chemicals and second, using two salts was dangerous. So we have decided to use neutralization method. HYPOTHESIS We predict that we will obtain 0.124 grams of CaCl2, because we used the correct stoichiometric amounts of the reactants HCl and Ca(OH)2 , according to the mole ratio for their reaction. VARIABLES To prepare the right amount of salt, we had to keep the temperature stable. We used room temperature. Although we heated the beaker, we let it cool down before measuring its mass. Another constant variable was concentration. We had to keep it still so that there wouldnt be a change in the reaction. Everybody in the class prepared different salt so everybody had different kinds of ions and since the salts were different, their solubility was different too. MATERIALS AND EQUIPMENT Beaker 100 ml 0.0815 grams of HCl 0.0828 grams of Ca(OH)2 Plastik dropper Scale Heater Spatula PROCEDURE 1) First of all, we decided which acid and base we should use. Since we had HCl and Ca(OH)2 in chemistry lab, we decided to use this acid and base. 2) We wrote the chemical equation of the reaction. 2HCl + Ca(OH)2 2H2O + CaCl2 We used HCl acid and Ca(OH)2 base. When an acid and a base react, they form water and a salt. After writing down the products and reactants, we balanced the equation. 3) In order to make 0.124 grams of salt, we needed to know the amount of reactants we should use. To find out, we used stoichiometry. 2HCl + Ca(OH)2 2H2O + CaCl2 2 moles 1 mole 2 moles 1 mole H:1.01 Ca:40.08 H2:2.02 Ca:40.08 Cl:35.45 O2: 32.00 O:16.00 Cl2:70.9 (35.45+1.01)à ¯Ã‚ ¿Ã‚ ½2 H2: 2.02 (2.02+16.00)à ¯Ã‚ ¿Ã‚ ½2 Mr: 72.92 grams Mr: 74.1 grams Mr: 36.04 grams Mr: 110.98 grams 72.92à ¯Ã‚ ¿Ã‚ ½0.124à ¯Ã‚ ¿Ã‚ ½110.98= 0.0815 grams of HCl (which is 20 drops) 36.04à ¯Ã‚ ¿Ã‚ ½0.124à ¯Ã‚ ¿Ã‚ ½110.98= 0.0828 grams of Ca(OH)2 4) We measured exactly 0.0828 grams of Ca(OH)2 . 5) We added 20 drops of HCl into the Ca(OH)2. 6) To have only salt as a product, we needed to heat the beaker so that the water would evaporate. After we heated the beaker for several minutes, we let it cool. 7) When the beaker was cool enough, we measured the salt and the beakers mass. It was 32,5097 à ¯Ã‚ ¿Ã‚ ½0,0005 grams. To make sure that there was no water, we decided to heat and measure it again. 8) The second time we heat and cooled and measured it, we found 32, 4896 à ¯Ã‚ ¿Ã‚ ½0,0005 grams. 9) Then we washed the beaker and measured it when its empty. We found 32.3551à ¯Ã‚ ¿Ã‚ ½0,0005 grams. 10) We subtracted the beaker and the salts mass from the empty beakers mass to find salts mass. The salts mass is 0,1345à ¯Ã‚ ¿Ã‚ ½ 0,0005 grams. Our aim was to prepare 0.124 grams of CaCl2 salt. RAW DATA PROCESSED DATA 1st Measurement (à ¯Ã‚ ¿Ã‚ ½0,00005 g) 2nd Measurement (à ¯Ã‚ ¿Ã‚ ½0,00005 g) Beaker+Salt Salt Beaker+Salt Salt 32,5097 à ¯Ã‚ ¿Ã‚ ½0,0005 g 0.1546 à ¯Ã‚ ¿Ã‚ ½0,0005 g 32, 4896 à ¯Ã‚ ¿Ã‚ ½0,0005 g 0,1345 à ¯Ã‚ ¿Ã‚ ½0,0005 g CONCLUSION Our aim was to create 0,124 grams of calcium chloride. In order to prepare the salt, we used a base and an acid. To achieve our aim, first we decided which method we should use to prepare this salt. We had two options because we didnt have other materials. We could have used either two salts or a base and an acid. After deciding to use a base and an acid, we used stoichiometry, which is a quantitative branch of chemistry. Stoichiometry is the science of measuring the quantitative proportions or mass ratios in which chemical elements stand to one another(Jeremias Benjaim Richter, 1762-1807). We calculated the amount of chemicals we should use. Then we started preparing our salt and reacted base with the acid. After heating the beaker to eliminate water, we get our salt. We measured it and found out that we prepared 0,1345 à ¯Ã‚ ¿Ã‚ ½0,0005 grams of CaCl2 salt. The reason why we get water and a salt when we react bases and acids is simple. Everything started with Swedish chemist Jons Berzelius, who said that acids and bases have opposite charges. After that the Arrhenius Theory explained that an acid is a compound which produces hydrogen ions and a base is the one that produces hydroxide ions when dissolved in water. Then as the Bronsted-Lowry Theory indicated, when an acid behaves like a donor (an acid as an H+ ion), it means that the hydrogen ion is separating from the acidic compound and when a base behaves like an acceptor (a base as an H+ ion), the hydrogen ion is bonding with the basic compound. Because water molecules are polar, the negative charges tend to congregate on one end of the molecule with the oxygen atom, while the positive charges remain on the other end with the hydrogen atoms. The Brà ¯Ã‚ ¿Ã‚ ½nsted-Lowry model emphasizes the role played by water, which pulls the proton from the acid, resulting in the creation of the hydronium ion (Zumdahl, Introductory Chemistry: A Foundation). Then finally with the Lewis Theory, which extends Arrhenius and Bronsted-Lowry theories, it was discovered that bases gives electrons and acids accepts them. So, an acid and a base react, since they attract each other. And when they react, the base generates OH+ and the acid generates H+ which forms water. And the other ions react to form a salt. With this experiment we not only used what we have learned about preparing salts but we also used stoichiometry, which is a very important topic in chemistry. We did all the calculations and the experiment ourselves and we get to apply our knowledge. EVALUATION Although the result we get was really close, we didnt exactly find 0.124 grams of CaCl2. The percentage error of the experiment is %9. We found 0.1345 à ¯Ã‚ ¿Ã‚ ½ 0,0005 grams. To make this experiment better, first of all we could have research our salt and learn more about it. We didnt know that Ca(OH)2 is hygroscopic in the first time we measured its mass. Thats why its mass may have been measured more than it should be. But the second time we measured the beaker, we were more careful however still when we let the beaker to cool, its mass might have increased. After we heated the beaker, we waited for several minutes and waited it to cool but the beaker and the salt within might have been still warm. If we measured salts mass when it was still hot, that means we found the mass more than it should be. If we had more time, maybe we could be sure that it was in the room temperature and then measure it. Although we cleaned the beaker after the experiment, we might have left salt in it and when we measured empty beakers mass, we might have found something wrong. We could have cleaned it more neatly. REFERENCES Calcium Chloride SIDS Initial Assessment Profile, UNEP Publications, SIAM 15, Boston, October 22-25, 2002, pages 4, 12-14. Zumdahl, Steven S. Introductory Chemistry: A Foundation, 4th ed. Boston: Houghton Mifflin, 2000. www.answer.com www.wikipedia.com

Societies Case for Censorship. :: essays research papers

Pornography and obscenity is all we see and hear about today in the news, with no exception to most movies and even TV. As of 12 years old this issue strikes a bigger interest than in the past. When I flip through the channels and see the news or watch a TV show there is something always on that a younger child should not be watching or learning about unless they are older. When the world censorship is thrown around it is a very controversial issue with the rights of the people and the way the company’s want to present their product.   Ã‚  Ã‚  Ã‚  Ã‚  When Irving Kristol wrote his article â€Å"Pornography, obscenity and the case for Censorship† he was putting down his views and his opinions the topic of censorship and all the other obscenities in the world. Kristol is proposing a very conservative and clean way to view American literature with all its freedoms to publish what ever is wanted. When reading his article it brings up many different points such as her main point of; â€Å"for the plain fact is that we all believe that there is a point at which the public authorities ought to step in to limit the ‘self-expression’ of an individual or a group†(604), this is exactly the way I feel on the topic.   Ã‚  Ã‚  Ã‚  Ã‚  When reading this article you have to look at the central claim that the author is making and agree with him or disagree. when going through this reading there where areas of its claims that have you thinking about our society and culture as a whole, that we are a species that loves its different types of uncensored media as well as its pornography and violence in their sports and everyday lives, â€Å"no society can be utterly different to the ways that its citizens publicly entertain themselves. Bearbaiting and cockfighting are prohibited only in part out of compassion for the animals; the main reason is that such spectacles were felt to debase and brutalize the citizenry who flocked to witness them† (604).   Ã‚  Ã‚  Ã‚  Ã‚   When Kristol speaks about his ideas of censorship; his claim that one day, not now but someday soon that the government is going to have to take this issue of censorship within a society and place in their hands. In essence Kristol is saying that this issue of censorship is not being carried out forcefully enough and it is hurting our society in the long run.

Coach Handbag analysis Essay

Company overview Designing and marketing of accessories and gift products for women and men. The company primarily operates in the US and Japan. It is headquartered in New York City, New York and employed 18,000 people as of June 30, 2012. 36% market share as accordance of Marketline In just two years (2003–2005), Coach’s market share has increased from 18 percent to 23 percent. TARGET MARKET DISCRIPTION men and women aged between 20s- 40s who possess mid to high levels of disposable income, seeking distinctive, easily recognizable, accessible luxury products that are relevant, well made, and provide excellent value (2012, 03). Mkt 501 Case Study Module 1 Target Market Coach Handbags. Retrieved 03, 2012, http://coachinc.wordpress.com/assignment-1/brand-positioning/competitor-analysis/ Product Life Cycle Shorten new-product cycle time (releases every four to five weeks, up from twice a year). Learn through multiple new-product variations (12 to 28 per release, up from two to three). http://mmoore.ba.ttu.edu/ValuationReports/Coach.pdf SWOT ANALYSIS – MARKETLINE UNDER COACH 2 STRENGTHS Strong focus on the handbags category Consistent revenue and profit growth Multi-channel distribution strategy WEAKNESSES Dependence on independent manufacturer for procuring merchandise OPPORTUNITIES Expanding presence in China Joint ventures with international partners in Europe Increasing online sales THREATS Counterfeit goods Ban on advertising of luxury products in China Intense competition started MISC INFO: Coach was launched in 1941 in a loft in New York’s Soho district by a leather craftsman named Miles Cahn, who created ladies’ purses designed in elegantly understated black or brown and featuring simple brass turnlocks and little other decoration. The bags were expensive but so well made that they were considered an excellent value. Coach was able to present the brand from head to toe, including products from hats and outerwear to handbags and accessories. One major breakthrough was the â€Å"wristlet,† a zippered rectangular bag just 4 by 6 inches. This new product grew out of Coach’s research into how women were using their purses. Coach spends over $5 million per year on marketplace testing of new products research shows that the best Coach customers visit the store every four to five weeks. This dictates the rhythm at which Coach rolls out its own products and floor-set changes.

Differences Between Dual Federalism And Cooperative...

What are the differences between dual federalism and cooperative federalism? Be sure to fully address what federalism is and why it was created. 1000 words. Dual federalism is a term used to describe a circumstance in which national and state governments are sovereign and equal within their constitutionally allocated spheres of authority. Federalism is a concept that refers to a system of government in which power is shared between the national and non-national governments. Cooperative Federalism is a model of federalism in which all governments are linked and participate in the administration of programs. Creative federalism was a term used to describe the Great Society program of Lyndon Johnson. President Johnson sought to devolve powers to the states using creative federalism. The devolution of responsibilities to the states began under President Nixon but were accelerated in the 1980s under President Reagan. Ronald Reagan s brand of new federalism dramatically decreased the use of categorical grants. Federalism under President Obama is still in the development stage, but the 2009 Federal Stimulus Plan can best be described as new federalism, creative, federalism, and general revenue sharing. There are four controversial examples of federalism at work today. A good example of federalism is usage of marijuana. Federalism, with its dual sovereignty, can create a patchwork of conflicting laws between the states as well as between the states and federal government.Show MoreRelatedDifference Between Dual And Cooperative Federalism848 Words   |  4 PagesCHAPTER THREE JOURNAL QUESTIONS: 1. WHAT IS THE DIFFERENCE BETWEEN A UNITARY AND A FEDERAL SYSTEM OF GOVERNMENT? The primary difference in these two models is their lines of power. 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