Types of chemical reactions lab Essay Example for Free

Types of chemical reactions lab Essay Copper (II) sulfate pentahydrate crystals are light blue and granular. After being heated, the crystals turned into a white powder and condensation formed in the upper part of test tube. It is represented by the equation CuSO4†¢5(H2O)(s) CuSO4(s) + 5(H2O)(g) When 5 drops of water were added to the white powder, bubbling occurred and the powder turned into a blue liquid, and then into the original blue coloured crystals (copper (II) sulfate pentahydrate). It is represented by the equation CuSO4(s) + 5(H2O)(l) CuSO4†¢5(H2O)(s) B Sodium sulfate solution is a colourless, transparent liquid. Barium chloride is a colourless, transparent liquid. After adding a medicine dropper of barium chloride solution, the solution immediately became cloudy and milky looking. A precipitate was formed during the reaction. It is represented by the equation BaCl2(aq) + Na2SO4(aq) BaSO4(s) + 2NaCl(aq) D Solid magnesium is a slightly shiny and malleable metal. Hydrochloric acid is a colourless, transparent liquid. After adding hydrochloric acid, magnesium began to fizz, releasing bubbles. The bottom of the test tube got warmer. Condensation formed in the upper part of test tube and the magnesium looked white and got much smaller. The reaction is represented by the equation Mg(s) + 2HCl(aq) MgCl2(aq) + H2(g) E Potassium iodide is a white granular solid. Hydrogen peroxide is a cooler than air, colourless, transparent liquid. After adding hydrogen peroxide, potassium iodide solids disappeared, followed by bubbling and colour change of solution to yellow, but still transparent. Temperature of solution is still cooler than air. After inserting a glowing splint into the mouth of the test tube, a pop sound is made and the flint is re-ignited. But the flame quickly died. The reaction is represented by the equation 2H2O2(aq) ––KI 2H2O(l) + O2(g) F The iron nail is a hard, shiny, grey, metal solid. The copper (II) sulfate solution is a light blue, translucent liquid. After the iron nail has been immersed in the copper (II) sulfate solution for a while, it had chunks of reddish brown rust-like substances on it. The reaction is represented by this equation CuSO4(aq) + Fe(s) FeSO4(aq) + Cu(s) Conclusion Experiment A demonstrated a decomposition reaction and a synthesis reaction. The decomposition reaction occurred when copper (II) sulfate pentahydrate was heated. The compound decomposed to copper (II) sulfate and water. The water is the condensation. Exposure to heat is what caused this products decomposition, so it is an endothermic reaction. The reason for this is that for chemical reactions to happen, at the smallest scale, the individual chemical molecules have to bump into one another. As molecules warm up they begin to vibrate more and the chances of them bumping in to one another increases the more bumps that happen, the faster the reactions go. It is represented by the equation AB A + B or (in the case of the lab) CuSO4†¢5(H2O)(s) CuSO4(s) + 5(H2O)(g) The synthesis reaction occurred when water was added to copper (II) sulfate. The compound synthesized to copper (II) sulfate pentahydrate. Synthesis can occur when one compound or molecule is introduced to another. It is represented by the equation A + B AB or (in the case of the lab) CuSO4(s) + 5(H2O)(l) CuSO4†¢5(H2O)(s) Experiment B demonstrated a double displacement reaction/precipitate reaction. The reaction occurred when aqueous sodium sulfate and aqueous barium chloride were mixed together. The milky precipitate is BaSO4, which was a product of the reaction. The compound is a precipitate because it is insoluble (says so on the solubility table). In double displacement reactions two ionic compounds switch cations. In order to switch cations, the ions must first be separated, in a solution for example, so that they may react with other ions present. A precipitate forms because the combination of a positive and a negative ion in solution forms a compound that is insoluble in water and precipitates out of the solution. The precipitate ions cannot re-dissolve in the mixture so they are rapidly removed from the solution. Double displacement is represented by the equation AB + CD AD + CB or (in the case of the lab) BaCl2(aq) + Na2SO4(aq) BaSO4(s) + 2NaCl(aq). Experiment D demonstrated a single displacement reaction/exothermic reaction. The reaction occurred when hydrochloric acid was added to solid magnesium. Since Mg is higher than H on the activity series (more reactive), therefore Cl ions are more attracted to Mg ions and will leave H to bond with Mg. Mg is more reactive than H because it has two electrons in its valence shell, these two electrons are easily lost because they are far from the nucleus (compared to that of H) so there is less attraction, resulting in low ionization energy (energy needed to remove electrons) . Magnesium must lose its outer electrons in order to react. Hydrogen has one valence electron and it is closer to the nucleus (compared to that of Mg) so there is more attraction, resulting in higher ionization energy. Therefore it is easier for Mg to react (lose electron) compared to H. The bubbles are H2 gas forming. Heat was released so it is an exothermic reaction. An exothermic reaction is a chemical reaction that is accompanied by the release of heat. In other words, the energy needed for the reaction to occur is less than the total energy released. As a result of this, the extra energy is released, usually in the form of heat. Single displacement is represented by the equation. A + BC AC + B or (in the case of the lab) Mg(s) + 2HCl(aq) MgCl2(aq) + H2(g) Experiment E is a catalytic decomposition reaction. Hydrogen peroxide is an unstable compound that will decompose with time, just on exposure to sunlight or heat (energy), to make water and oxygen gas. It should be kept in an opaque container in a cool environment (hence the cool temperature). The rate of decomposition of hydrogen peroxide can be increased with a catalyst, like potassium iodide, which is a substance that speeds up a chemical reaction but remains chemically unchanged at the end of the reaction. The mechanism of catalysis involves the negative iodine ions only. The mechanism is a multi sequence reaction H2O2(aq) + I-(aq) IO-(aq) + H2O(l) H2O2(aq) + IO-(aq) I-(aq) + H2O(l) + O2(g) *When the IO ion was made, it would react with another H2O2 molecule until there were no more H2O2 molecules left. The second step regenerated the negative iodine ion (thus acting as a catalyst). The iodine ions were not affected by the reaction, meaning it did not bond with any other substances other than it had originally (potassium) by the end of the reaction. The iodine acted as a catalyst, it sped up the reaction without bonding in the end. The potassium did not play any role in the reaction, it was only bonded with iodine in the beginning. In fact, another substance with similar chemical properties as potassium, sodium for example, could have been bonded with iodine before the reaction, and the reaction would have been the same. Decomposition is represented by the equation AB A + B or (in the case of the lab) 2H2O2(aq) ––KI 2H2O(l) + O2(g) The glowing splint popped because it ignited hydrogen gas. But hydrogen gas was not made from the reaction so I assume it was in the air before. The hydrogen gas was oxidized, it combined with oxygen gas violently and quickly to form water. The oxidization caused vibrations which is the popping sound. The splint re lit because oxygen gas is also present. The fire died eventually because the oxygen had been used up in the test tube. The glowing splint test proved that the above reaction occurred, because when a glowing splint is exposed to O2 gas, it re-ignites and that is what had happened, it is a complete combustion because there was an excess of O2 gas. Experiment F is a single displacement reaction/precipitate reaction. The reaction occurred when iron and copper (II) sulfate came into contact. Since Fe is higher than Cu on the activity series, therefore SO4 molecules are more attracted to Fe ions and will leave Cu to bond with Fe. The precipitate created is copper, which collects on the nail. Single displacement reaction is represented by the equation A + BC AC + B or (in the case of the lab) CuSO4(aq) + Fe(s) FeSO4(aq) + Cu(s) Errors 1. After heating copper (II) pentahydrate, we did not allow the test tube to cool down fully before adding water. When water was added it began to boil and evaporate. This could have changed our results because we do not know if the evaporation took away substances from the test tube, so some substances that should be there may be missing. This will give us inaccurate results. 2. We may have handled the magnesium strip and the iron nail for too long. Contaminants on our skin such as oils or other chemicals could become residue on the magnesium and iron and react in the experiment, which would give us inaccurate results (shouldnt have happened). 3. There were people walking by the bunsen burner. The wind that their movement created may have affected the temperature of flame and thus the results.

Leprosy :: essays research papers

Leprosy Leprosy or Hansen’s disease, is a chronic, infectious disease that mainly affects the skin, mucous membranes, and nerves. A rod shaped bacillus named Mycobacterium leprea, causes the virus. Mycobacterium leprea is very similar to the bacillus that causes tuberculosis. The reason Leprosy is also known as Hansen’s disease, is because it was first identified in 1874 by a Norwegian physician named Gerhard Henrik Armeur Hansen. Leprosy appears in both the Old and New Testaments. In the bible Leprosy was not the disease that is recognized now, but as various physical conditions that were nothing like the disease. A punishment from God was what these conditions were considered to be. The victim was said to be in a state of defilement. This Hebrew term was translated as lepros, which the word leprosy came from.   Ã‚  Ã‚  Ã‚  Ã‚  The disease’s probable origin was the Indus Valley that is located in India. Leprosy spread from there to the Mediterranean region and North Africa, then all of Europe was affected. This disease is much less common now, as the world case count has dropped below 1 million. During 1995 about 530 000 new cases of leprosy were discovered. It is obvious that third world countries have way more cases as India, Indonesia, and Myanmar account for almost 70% of the cases reported in the world. 5500 know cases of Leprosy still exist in the US, and about 200 cases a reported annually.   Ã‚  Ã‚  Ã‚  Ã‚  Tests to produce leprosy in experimental animals, have not been successful as of yet. Though the organism can be grown in Armadillos, several laboratories have been reported cultivating leprosy in the test tube.   Ã‚  Ã‚  Ã‚  Ã‚  Loss of sensation in a patch of skin is often the first symptom that Leprosy displays. In the lepromatous form, large area’s of the skin may become infiltrated. The mucous membranes of the nose, mouth, and throat may be invaded by large numbers of the organism. Because of damage to the nerves, muscles may become paralyzed. The loss of sensation that accompanies the destruction of nerves may result in unnoticed injuries. These may result in secondary infections, the replacement of healthy tissue with scar tissue, and the destruction of bone. The classic disfigurements of Leprosy, such as loss of extremities from bone damage or the so-called leoline facies, a lionlike appearance with thick nodulous skin, are signs of advanced disease, now

Racism in Football Essay

Throughout the 231 years football has been in existence, we are at the most critical era of football. In the last 10 years , the sport which had been invented to unite people of different colours , countries and religions .Has become a word which excruciates my heart . Racist. Racism was first encountered by the world in 1891 in a pub, full of intoxicated minds , the same act was discovered on a pitch full of sober men who get more than a soldier for being on the pitch. Racism itself means prejudice or discrimination directed against someone of a different race .Is It that footballer have developed this malicious habit of saying derogatory terms – then obviously not remembering it in a court room . There however has been more then a dozen cases reported of the years ( from maradona to suarez ) . Yet 77% of these cases have not been taken action on but the 33% which have been recognised only 11% have been taken to the high court and found justice . this does leave a controversi al question in our mind is it the F.A ( Football Association ) behind this ? A more recent case on racism and football is the Blackburn skipper Jason Robert’s decision to boycott wearing the ‘kick racism out of football’ t-shirt, for Saturdays pre-match warm up against Swansea . This is because the Reading striker believes there is a lack of commitment from the F.A and football in progressing and until he is satisfied more has been done to address racism in football he will not wear the t-shirt again . Also as A number of black players – Rio fernidad and brother Anton fernidad , Ashley Cole , Raheem sterling have all joined Roberts with the decision of boycotting the t-shirt because they also believe there is insufficient progress . Conversely there are some footballers that do follow the F.A code of conduct , and also do that little bit of an extra aid , such as craig bellamy who has opened his own academy in Zambia . However there is always that small minority in every population , that weigh the majority of people down . Also most racist incidents occur between player of rival teams – but this is no excuse for racism . As a result of this barbaric culture of using racist terminology , the sport has began to suffer verbally from various organisations .The sport which was made to unite people of different colours , countries and religions is becoming segregated . I know your thinking â€Å" I cant make a difference â€Å" . But I can , you can and we can .

About A Technological Unemployment - Free Essay Example

Sample details Pages: 2 Words: 708 Downloads: 9 Date added: 2019/05/31 Category Society Essay Level High school Tags: Unemployment Essay Did you like this example? Self-checkout machines have been starting to show up everywhere, from the local Walmart to stores across the globe. Before these machines came to fruition, those areas used to house employee operated check-out machines. Those employees were eventually replaced for a faster and easier check-out method. Knowing that your livelihood and job can be deterred by a simple, inanimate object is a hard reality. Every new machine developed to increase industry productivity leaves hardworking individuals being left without a job and it is seemingly only going to increase. Ever since the Industrial Revolution, technological improvements have been a great value to employers over the country. Before the Industrial Revolution, agriculture work was a massive source of employment. There was such a high demand for the products and it required a substantial amount of work for the farm to make a profit. The agriculture industry, along with many others, exploded with new innovations whenever machines made their first appearance in the workforce. Harvesting machines such as the cotton gin and spinning jenny have allowed producers to rapidly produce their goods while saving the cost of labor. While the machines did make the farmerrs jobs easier, there was also a huge decline in the number of farmers needed. This forced the workers to work in industrial jobs, which fueled the Industrial Revolution even more so. Don’t waste time! Our writers will create an original "About A Technological Unemployment" essay for you Create order Technology has been improved and modified for centuries with the goal of improving workplace productivity. However, current circumstances are relatively unique than in years past. The human population is spreading like wildfire, every few years increases the population by billions. Business owners want their businesses to be as cost-efficient as possible. A machine does not need a paycheck, vacation, sick days, or even rest. Naturally the business will save more money by replacing their workers with advanced machines. These newly potential workers could be left without a job. Potentially no job is safe from replacement if the rate of technological advancement carries on as it has for the past couple years. If machines continue to grow at this extraordinary rate, the nation could collapse from a horribly skewed balance of wealth. Productivity will reach an all-time high from all sectors. However, unemployment will also skyrocket. There will then be an all-time low in purchasing power. This is especially true if the labor market is inflexible. For example, coal mining used to be a huge source of labor and wealth, especially during the 1920s. As the coal runs out in the area, and better energy methods started to appear, these coal miners started to lose their jobs. These miners often cannot take up a new job due to an occupational and/or geographical immobility. They most likely do not have the necessary skills to work a new job, and they might live far away from the workplace. This resulted in a temporary unemployment surge until they could learn the skills required or could move to a more prosperous part of the area. An alternative idea of technological change is that it will not cause unemployment. Technological change in the food industry means we can produce food with fewer workers. It is then cheaper, to produce food and the price to buy food will fall. This means that a smaller income percentage will go towards buying food, so they have more money for other goods and services (especially manufactured goods). This increased demand for manufactured goods causes higher demand, therefore there will be a higher demand for workers. This is just innovation with technology, the types of jobs will change not be replaced. If labor productivity increases, we can then enjoy a greater range of goods and services. Businesses and corporations have been integrating new technology and advanced machinery into their work procedure for over a century, resulting in less workers needed. The laid off people just needed to learn new skills to work the machinery. If the robots become capable of doing the same job the human once did (such as the check-out machines), they will no longer have a role in the workplace. It is unsure how increased technology will shape the job market in the future. The only thing certain is that integrating new machines make the business/production process run more effective and cost-efficient.