Complexometric Determination of Water Hardness Essay Example for Free

Complexometric Determination of Water Hardness Essay When a polyatomic ligand with multiple lone pairs of electrons available for bonding to a central metal ion forms a complex with a metal ion, a process known as chelation takes place. Metal ion impurities can be found by using disodium salt of EDTA to determine the concentration of M2+ by complexometric or chelometric titration. Erichrome Black T makes it easy to see when the EDTA has completely chelated the metal impurities. When the metal cation is still present in the water, the solution will be a complex with a pink tint. Once enough EDTA has been added to the M2+ solution the metal ions complex to the EDTA leaving the indicator solvated causing a color change from pink to blue. Once the color has changed to blue, the titration has reached an end point and the M2+ metal ion impurities in hard water can be calculated. Procedure: Prepare 500 mL of 0.004 M disodium EDTA solution by dissolving 0.7-0.8g of Na2EDTA in 500 mL deionized water. Standardize the solution by using a 10 mL transfer pipet to add 10 mL of standardized calcium ion stock solution to a 250 mL Erlenmeyer flask and mixing it with 30 mL of deionized water. Add 3 mL of ammonia/ammonium chloride buffer (pH 10) to ensure that the calcium ions remain in the solution for accurate results. Add four drops of Eriochrome Black T indicator solution so that a color change can be visible during titration. Once the solution is prepared, titrate it with the disodium EDTA solution. Add the solution quickly at first and once the color changes from pink to violet slow down the titration until the color changes from violet to blue. Then record the results. Part 2 Unknown After receiving an unknown prepared water sample record the unknown in your lab notebook (unknown #76). After the unknown has been recorded, transfer 25 mL of the sample into a 250 mL Erlenmeyer flask with 20 mL of DI water. As in part one, add 3 mL of ammonia/ammonium chloride buffer (pH10) to the solution along with four drops of Erichrome Black T indicator. Once the solution has been made, titrate the solution with the standardized disodium EDTA solution and calculate the hardness of the prepared water sample from the titration. Compare the results to the expected range for municipal water hardness on your city’s water quality lab website. Data: | Test 1: Standardization of EDTA Mass of CaCO3: 0.01 g Moles of CaCO3: 9.910^-5 Molarity of the 250 mL standard Ca2+: 3.9610^-4 M Column1| Trial 1| Trial 2| Trial 3| Volume of Ca2 Titrated (mL)| 10| 10| 10| Moles Ca2+ Titrated | 9.910^-5| 9.910^-5| 9.910^-5| Moles EDTA| 9.910^-5| 9.910^-5| 9.910^-5| Initial Buret reading (mL)| 1| 1| 1| Final buret reading (mL)| 26.3| 26.5| 27| Volume of EDTA (mL)| 25.3| 25.5| 26| Molarity of EDTA (M)| 0.0039| 0.0039| 0.0038| Average Molarity of EDTA| | 0.0039 M| | Test 2: Unknown Determination Sample #76 Column1| Trial 1| Trial 2| Trial 3| Volume of Water Sample Used (mL)| 25| 25| 25| Initial buret reading (mL)| 1| 1| 1| Final buret reading (mL)| 14.8| 15| 14.9| Volume of EDTA used (mL)| 13.8| 14| 13.9| Moles EDTA| 5.3810^-5| 5.4610^-5| 5.4210^-5| Moles Ca2+ in sample| 5.3810^-5| 5.3810^-5| 5.3810^-5| Moles Ca2+ per liter| 5.3810^-4| 5.3810^-4| 5.3810^-4| Grams CaCO3 per liter| 0.054| 0.055| 0.055| Water hardness| 29.73| 30.61| 30.17| Average water hardness (ppm CaCO3)| | 30.17| | | | | | | | | | | | | | Calculations: Test 1: Calculate Mass of CaCO3 used in the reaction: 10 mL Ca2x 1L/1000mLx 1g/1L= 0.01 g CaCO3 Calculate Moles of CaCO3 0.01 g CaCO3x 1mole CaCO3/100.1 g CaCO3= 9.910^-5 moles CaCO3 Molarity of 250 mL of standard Ca2+ solution 9.910^-5 moles CaCO3/0.250 L= 3.9610^-4 M Ca2+ Moles Moles of EDTA Moles of EDTA=Moles CaCO3, 1 to 1 ratio. Molarity of EDTA Trial 1 (10 mL CaCO3 sol/25.6 mL EDTA @ end point)x (1L CaCO3 Sol/1000mL CaCO3 sol)x(1 g CaCO3/1 L sol)x(1 mole CaCO3/100.1g CaCO3)x(1 mole EDTA/1 mole CaCO3)x(1000 mL EDTA sol/1 L EDTA sol) = 0.0039 M Trial 2 (10 mL CaCO3 sol/25.5 mL EDTA @ end point)x (1L CaCO3 Sol/1000mL CaCO3 sol)x(1 g CaCO3/1 L sol)x(1 mole CaCO3/100.1g CaCO3)x(1 mole EDTA/1 mole CaCO3)x(1000 mL EDTA sol/1 L EDTA sol) =0.0039 M Trial 3 (10 mL CaCO3 sol/26 mL EDTA @ end point)x (1L CaCO3 Sol/1000mL CaCO3 sol)x(1 g CaCO3/1 L sol)x(1 mole CaCO3/100.1g CaCO3)x(1 mole EDTA/1 mole CaCO3)x(1000 mL EDTA sol/1 L EDTA sol) =0.0038 M Average Molarity (0.0039 M+0.0039 M+0.0039 M)/3=0.0039 M Test 2: Calculate moles of EDTA Trial 1 0.0138 L EDTA(3.910^-3 moles EDTA)= 5.8310^-5 Moles EDTA Trial 2 0.014 L EDTA(3.910^-3 moles EDTA)= 5.4610^-5 Moles EDTA Trial 3 0.0139 L EDTA(3.910^-3 moles EDTA)= 5.4210^-5 Moles EDTA Moles Ca2+ Moles of Ca2+ equals moles of EDTA Moles of CA2+ per liter Moles Ca2+ x 10 to get Moles per leter Trial 1 5.8310^-5 Moles EDTA(10)= 5.3810^-4 Moles Ca2+ per Liter Trial 2 5.4610^-5 Moles EDTA(10)= 5.4610^-4 Moles Ca2+ per Liter Trial 3 5.4210^-5 Moles EDTA(10)= 5.4210^-4 Moles Ca2+ per Liter Grams CaCO3 per liter Calculate by multiplying moles of Ca2+ by grams per mole of Ca2+ Trial 1 (5.3810^-4 Moles Ca2+/ 1L)(101.1g/1mole)= 0.054g/L CaCO3 Trial 2 (5.4610^-4 Moles Ca2+ /1L) (101.1g/1mole)= 0.055g/L CaCO3 Trial 3 (5.4210^-4 Moles Ca2+ /1L) (101.1g/1mole)= 0.055g/L CaCO3 Water Hardness Trial 1 (13.8 mL EDTA/25 mL sample)(1 L EDTA sol/1000 mL EDTA)(5.3810^-4 mol EDTA/1L EDTA)(1 mol CaCO3/1 mol EDTA)(100.1g CaCO3/1 mol CaCO3)(1000mg CaCO3/1g CaCO3)(1000mL Sample sol/1L sample sol)= 29.73 ppm CaCO3 Trial 2 (14 mL EDTA/25 mL sample)(1 L EDTA sol/1000 mL EDTA)(5.4610^-4 mol EDTA/1L EDTA)(1 mol CaCO3/1 mol EDTA)(100.1g CaCO3/1 mol CaCO3)(1000mg CaCO3/1g CaCO3)(1000mL Sample sol/1L sample sol)= 30.61 ppm CaCO3 Trial 3 (13.9 mL EDTA/25 mL sample)(1 L EDTA sol/1000 mL EDTA)(5.4210^-4 mol EDTA/1L EDTA)(1 mol CaCO3/1 mol EDTA)(100.1g CaCO3/1 mol CaCO3)(1000mg CaCO3/1g CaCO3)(1000mL Sample sol/1L sample sol)= 30.17 ppm CaCO3 Average water hardness (29.73+30.61+30.17)/3= 30.17 ppm CaCO3 Conclusion: The water hardness of a known and unknown sample solution has been determined by means of titration with disodium salt of EDTA to calculate the concentration of M2+ metal ion impurities in hard water in a process known as chelation. After running tests and calculating the water hardness in an unknown sample it was found that there was 30.17 ppm CaCO3 in the sample.

Barbed Wire By Mary Emeny :: essays research papers

Mary Emeny’s poem, â€Å"Barbed Wire,† depicts war as a negative force, destroying every decent aspect of human existence. Written during the Vietnam War, the work displays Emeny’s negative views on war. In one way or another everyone experiences and identifies with the presence of war. Although some wars are fought for justifiable reasons, every war tears into the lives of those undeserving. The tragic effects of war consume the innocent creating an unconquerable path of entanglement. The physical effects of war overwhelm the naà ¯ve causing pain and suffering. Initially, war entangles the lives of youth, destroying the innocence that they experience as an aspect of their life. The girl â€Å"glid[ing] gracefully down the path† (1) and the boy â€Å"rid[ing] eagerly down the road† (9) have their enjoyable realities striped by the harshness of war. Likewise, war enters women’s lives creating turmoil. The woman who works â€Å"deftly in the fields† ( ) no longer is able to experience the offerings of life. The â€Å"wire cuts,† ( ) pushing her away from the normal flow of life. In addition, man undergoes tragic obstacles as a result of war. â€Å"A man walks nobly and alone† ( ) before the horrible effects of war set in on his life causing disruptions. War enters the life of man destroying the bond man shares with his beloved environment ( ). Although a great deal of physical effects exist in Emeny’s work, the spiritual consequences of war serve as the most devastating ones. The will and spirit of those amidst the harshness of war diminishes because of the seriousness of war. Prior to the complexities of war, the â€Å"spirit flees gleefully to the clouds,† ( ) illustrating the freedom one expresses without repression. As soon as the â€Å"wire catches,† ( ) or the war commences, and intervenes with the lives of innocent bystanders, the innocence is lost. Furthermore, the hearts of the untainted human beings experience demolition due to the irrationality of war. Before the tragedy of war enters the picture, a heart â€Å"goes openly to the street,† ( ) showing the freedom that one possesses until the â€Å"wire snares,† ( ) and the sense of innocence disappears. Significantly, as a direct result of the entanglement of war, man’s mind suffers pain and misfortune. A man’s min d â€Å"grows in searching† ( ) preceding the brutality of war, exhibiting the ability of man to explore his surroundings without interference.

Technology and learning

The modernization of the times led to a startling reality that the world will be crippled without the aid of technology. Technology is becoming more and more of a necessity these days in all aspects of daily living and as such, educational institutions have incorporated this subject in their curriculum because the authorities acknowledged the fact that technology can help attain student objectives and in order to achieve the maximum impact, it must form part of the school's education curriculum (Neir Tech, 2002).English is a subject that would be greatly enhanced by technology. English is a diversified field in itself that requires self-expression, vocabulary, reading, creativity and innovativeness of the mind. Technology can greatly enhance the students' learning process when it comes to English because the information that they need is just a few clicks away. The world wide web provides a wide array of information and lectures about all English subjects. For example, a student havi ng difficulty in pronunciation and vocabulary can access the Internet to learn this kind of skill.Students who have been assigned difficult topics for assignment can search the net for all the information that he needs. The teachers can use the technology as aid in teaching not only English but other subjects as well by using highly-powered technology driven lectures that would work best in capturing students' attention. There are some schools that use technology to breach the barriers of communication. Video conferencing is another technological development that greatly helps educational institutions teach students not only English but other subjects as well.ReferencesNeir Tech. 2002.   Strategies for Improving Academic Achievement and Teacher Effectiveness. Retrieved July 3, 2009, from http://www.neirtec.org/products/techbriefs/1.htm

Ludwig van Beethoven Essay - 952 Words

Some of the most well known composers came to be in the in the classical music period. Ludwig van Beethoven was one of the composers, along with other greats of the time like Haydn and Mozart, which helped to create a new type of music. This new music had full rich sounds created by the new construction of the symphony orchestra. Ludwig van Beethoven was born in the town of Bonn, Germany on December 16 of 1770. Bonn is located in western Germany on the Rhine River. Beethoven showed an affinity for music at an early age. His father, Johann, taught Ludwig to play the piano as well as the violin. Johann did this in hopes that his son would become a prodigy, and then reach fame like Wolfgang A. Mozart. Unfortunately though Beethoven†¦show more content†¦Regrettably, though in the late 1790s Beethoven began to lose his hearing. Then at the start of the 1800s Beethoven changed the way he created music and his personality because of the increasing deafness. Prior to the i ncreasing loss of hearing Beethoven had been full of pride and independent, though a little odd. When his hearing started to go he changed, he became more apprehensive and ill tempered. Despite becoming absolutely deaf by the end of his life Beethoven’s works were still brilliant. It was on March 26, 1827 when Beethoven died, the cause was a simple cold that turned into pneumonia and then later dropsy. Beethoven’s works are classified into three periods. Beethoven’s first period took place between the 1780s to approximately 1800. The works produced during this period show the Beethoven was just beginning his musical journey. The pieces created are similar to ones created by Haydn, Mozart, Bach, and Neefe. Christian Neefe was one of Beethoven’s instructors from Bonn. Despite the fact that Beethoven modeled his early works after others they still showed his personality in the way they were written and in their robust melodies. In Beethoven’s second period he generated many of his most famous works. This period lasted from about 1800 to 1820. It was in this time span that Beethoven wrote symphonies three through eight, two piano concertos, one violinShow MoreRelatedLudwig Van Beethoven945 Words   |  4 PagesLudwig van Beethoven Beethoven was born in Bonn, Germany in 1770 to Johann van Beethoven and his wife, Maria Magdalena. He took his first music lessons from his father, who was tenor in the choir of the archbishop-elector of Cologne. His father was an unstable, yet ambitious man whose excessive drinking, rough temper and anxiety surprisingly did not diminish Beethoven s love for music. He studied and performed with great success, despite becoming the breadwinner of his household by the time heRead More Ludwig Van Beethoven Essay1285 Words   |  6 Pages German composer and pianist, Ludwig van Beethoven, was born December 1770 and spent most of his life in Vienna, Austria. 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There has been many great composers throughout the years, these people are legends that will stand for ever such as, Beethoven, George Frideric Handel, and Wolfgang Amadeus Mozart. The one artist that I’m going to write about in this paper is the one and only Ludwig van Beethoven. Beethoven was a deaf German