Experiment 4 Rdr - Chemical Equilibrium Essay Example for Free

Experiment 4 Rdr Chemical Equilibrium Essay Iron-Silver Equilibrium In the first phase of the experiment, iron sulfate was mixed with silver nitrate, and the reaction produced solid silver and iron nitrate, which is formally written as, Fe2+ (aq) + Ag+ (aq) ⇄ Ag (s) + Fe3+ (aq) The mixture was then placed in a centrifuge in order for the solid silver to settle and separate from the supernate. The supernate was then tested for the presence of Fe2+, Fe3+ and Ag+ by placing K3Fe(CN)6, KSCN and HCl to 3 separate samples of the supernate. The result of the tests was as follows: 1.Addition of K3Fe(CN)6 After K3Fe(CN)6 was added to the supernate, a Prussian blue precipitate was formed, more formally written as, Fe2+ (aq) + Fe(CN)63- (aq) + K+ (aq) → K∙Fe2(CN)6 (s) This reaction thus proves that the supernate contains Fe2+. 2.Addition of KSCN After KSCN was added to the supernate, a blood red complex was formed, more formally written as, Fe3+ (aq) + SCN- (aq) → FeSCN2+ (aq) This reaction thus proves that the supernate contains Fe3+. 3.Addition of HCl The last test was the addition of HCl to the supernate. This produced a white precipitate, which we can formally write as, Ag+ (aq) + Cl- (aq) → AgCl (s) This reaction thus proves that the supernate conatins Ag+. The 3 tests showed that all 3 ions were present in the supernate. This goes to show that the reaction between iron sulfate and silver nitrate was in a state of equilibrium since both the ions in the product and reactant side were present, meaning to say that the forward and reverse reactions were proceeding at the same rate. Furthermore, the range of the equilibrium constant (Keq) for the reaction of iron sulfate and silver nitrate is from 10-10 to 1010 [1]. Copper-Ammonia Equilibrium The second phase of the experiment dealt with the reaction between copper sulfate and ammonia, more formally written as, CuSO4 (aq) + 2 NH4OH (aq) → Cu(OH)2 (aq) + (NH4)2SO4 (aq) The pale blue precipitate formed at the beginning of the reaction of copper sulfate and ammonia was the Cu(OH)2. From the pale blue color, it turned into a deep cerulean blue when 11 drops of ammonia was added. The solution then went back to the pale blue color after 4 drops of hydrochloric acid was added. The addition of hydrochloric acid added more H+ ions to the solution; therefore, drawing the equilibrium back to the reactant side. This equilibrium reaction is formally stated as, [Cu(H2O)6]2+ (aq) + 4 NH3 (aq) ⇄ [Cu(NH3)6]2+ (aq) + H2O (l) As observed, it took almost 3 times the number of drops of ammonia to change the pale blue color to a deep cerulean blue as compared to the number of drops of hydrochloric acid that changed the deep cerulean blue back to pale blue. This means that the reverse reaction was more spontaneous than the forward reaction. Chromate-Dichromate Equilibrium In the third phase of the experiment, the chromate and dichromate solutions were observed. Chromate had a yellow color, while dichromate had an orange color. When sulfuric acid was added to a sample of chromate and dichromate solutions, the yellow chromate solution turned orange, while the dichromate solution remained orange. The equation for the chromate’s change in color is as follows, 2 CrO42- (aq) + 2 H+ (aq) → H2O (l) + Cr2O7- (aq) When sodium hydroxide was added to a sample of chromate and dichromate, the chromate solution remained yellow, while the orange dichromate solution turned yellow, formally written as, 2 OH- (aq) + Cr2O7- (aq) → 2 CrO42- (aq) + H2O (l) The change in color of chromate as hydrochloric acid was added and the change in color of dichromate as sodium hydroxide was added was due to the instability of the reactions, causing a shift in the equilibrium. The acid H2SO4 (sulfuric acid) was used in the reaction since it’s a strong acid, and strong acids dissociate more. The added H+ ions increase the concentration, therefore, shifting the equilibrium. Based on the observations made, it could be said that the dichromate solution is stable under acidic conditions, while the chromate solution is stable under basic conditions. Iron-Thiocyanate Equilibrium In the fourth phase of the experiment, iron trichloride was reacted to thiocyanate giving way to this reaction, [Fe(H2O)6]2+ (aq) + SCN- (aq) ⇄ [Fe(SCN)(H2O)5]2+ (aq) + H2O (l) The reaction produced a light orange solution, which was then tested to determine to which direction the equilibrium shifted when Fe3+, SCN- and NaCl were added. The result of the tests was as follows: 1.Addition of Fe3+ After FeCl3 was added to a sample of the solution, the light orange color of the solution became a darker shade of orange, which could be said to show a shift to the right. 2.Addition of SCN- After KSCN- was added to a sample of the solution, the shade of orange of the solution was lighter than the solution when FeCl3 was added, but darker than the original light orange color. It could then be said that the equilibrium shifted to the right. 3.Addition of NaCl Lastly, NaCl was added to a sample of the solution. It was observed that the resulting solution had a lighter shade of orange than that of the original. With this, it could be said that the equilibrium shifted to the left. The shift to the left of the equilibrium was brought about by the reaction of Cl- (from NaCl) with Fe(SCN)3. Cobalt-Cobalt Chloride Equilibrium The last and final phase of the experiment was on the reaction of cobalt dichloride and hydrochloric acid which could be formally written as, [Co(H2O)6]2+(aq) + 4Cl- (aq) ⇄ [Co(Cl)4]2-(aq) + 6H2O(l) The first part of this phase reacted cobalt dichloride with hydrochloric acid. The pink color of the cobalt dichloride (Co2+) turned blue (CoCl42-) when hydrochloric acid was added. In the second part of this phase, the test tube containing cobalt dichloride was immersed in a boiling water bath. The pink color of the solution turned blue when the temperature increased. With this, it could be said that the equilibrium shifted to the right upon heating. When the temperature is increased at constant pressure, an exothermic reaction would proceed backward or shift to the left. In this case, the increase in temperature made the equilibrium shift to the right; therefore, the reaction is said to be endothermic. CONCLUSION The experiment basically could be summarized into the 5 different equilibrium states. First, the iron-silver equilibrium states that reactants and products could indeed co-exist in a system. Second, the copper-ammonia equilibrium states that certain chemicals could affect the state of equilibrium of a system. Third, the chromate-dichromate equilibrium states that increasing the acidity or basicity of the solution could either move the equilibrium forward or backward. Fourth, the iron-thiocyanate equilibrium states that â€Å"An increase in the concentration of the reactant or a decrease in the concentration of the product shifts the direction of the reaction towards the production of more products to return to the equilibrium position. On the contrary, a decrease in the concentration of the reactants or an increase in the concentration of the product shifts the equilibrium position towards the production of more reactants.† [3] Lastly, the cobalt-cobalt chloride equilibrium states that an increase in temperature in an endothermic reaction favors product formation, therefore shifting the equilibrium to the right. On the contrary, increasing the temperature in an exothermic reaction favors reactant formation causing a shift to the left. RECOMMENDATIONS The methods and procedures done in the experiment are sufficient to obtain the data and results needed. No further recommendation is needed. REFERENCES [1] Petrucci, Ralph et.al. General Chemistry: Principles and Modern Applications, 10th ed.; Pearson Canada: Toronto, Ontario, 2010. [2] Padolina, Ma. Cristina et.al. Conceptual and Functional Chemistry: Modular Approach, Vibal Publishing House, Inc.: Araneta, Quezon City, 2004. [3] Chemical Equilibrium. [Online]. http://www.scribd.com/doc/30015115/Expt-9-Chemical-Equilibrium (accessed last January 15, 2013)

Strong Will :: essays research papers

  Ã‚  Ã‚  Ã‚  Ã‚  Have you ever felt you wanted something so badly you would give up your life for it? well often strong people , that means people with strong determination and will power, do. They don't exactly give up their life but put hard work and all their might into it. Strong people do as they wish and they also acomplish any goal they set themselves to. Throughout history there has been many examples of strong people but none of them compares to the example of Winston Churchill.   Ã‚  Ã‚  Ã‚  Ã‚  Winsotn Churchill was dedicated to his work and had a strong will. He is the vivid example of a determined man and his help in World War 2 is the best representation of what fighting for your beliefs means. He fought against the axis powers and obtained a great triumph. He set his goals strait and those were to liberate europe from all oppresion. He was the prime minister of Great Britain but some say he was the leader behind the whole allied side.He struggled year after year looking for a way to defeat the Germans and stop the war, he had a hard time acomplishing this and had to fight many battles both in the trenches and outside of them to achieve his goal. This shows the persistance and the strong will he had.   Ã‚  Ã‚  Ã‚  Ã‚     Ã‚  Ã‚  Ã‚  Ã‚  He had a lot of set backs and troubles in acomplishing his goals but due to his hard work and all his effort he carried out his plans. His men were dying in the western front and jewish people were getting killed due to Hitlers genocide, all this going through his head was alot to deal with but even though he organized himself and triumphed. This demonstrates how Winston Churchill faced adversity and beat it back with his own will power and conviction. His determination lead to his very own triumph. He knew that showing a strong arm was the best move because it showed a man with principles and who wasn't thinking on changing them. This inspired fear on German generals and influenced the outcome of the war. People who are strong in their character and decisions meet all their goals.   Ã‚  Ã‚  Ã‚  Ã‚  The day the war ended was the happiest in Winston's life because he felt like

Nature and Nature in Cognitive Development Essay

Why are both nature and nurture important in perceptual development? How do both help a baby’s brain and sensory organs to develop? The question of whether nature or nurture is more important in terms of perceptual development has bee long debated. In general, there are two theories that explain how humans develop these perceptions. The Nativists claim that our brains are built or hardwired to recognize certain stimuli by both design and construction. In contrast, an Empiricist would say that we learn through experience how to perceive things. There was an experiment done by Nativist researchers that sought to determine how very young mammals are able to perceive. The data concluded that early infants were able to perceive quite a lot before they really had a chance to learn anything. Gibson and Walk’s the â€Å"visual cliff† experiment was one such experiment, in this test both young animals and 6 month old human infants were taken to a side of a visual cliff, the test subjects would avoid the clearly deep drop. This indicated that children can perceive visual depth and that visual depth dominates even touch information. Additionally, studies have been done that show babies can recognize faces and that they often prefer the visual stimulation of carton faces as opposed to the same features arranged at random. In other tests it was shown that babies can also recognize whether or not and object is coming directly at their face or not. These experiments show that even the undeveloped infant brain has considerable capacity for perceptual capabilities. In contrast, several Empiricists experiments have been done as well. In one such study, scientists sought to determine the effects of depriving developing animals from perceptual stimulations. These tests have consistently shown that the longer the subject is deprived, the more severe the consequences. For example, humans are sometimes born without sight, due to a clouded cornea. Later in life some elect to have surgery to repair this clouded cornea. The result is sight, these people can see but they cannot perceive what it is that they see. As time goes on they slowly learn to distinguish one object from another, but this is however quite easily interrupted. Often changing an objects position or context is quite enough to slow down or prevent recognition. To conclude, although some argue that perception is due to nature, while others argue for nurture, it may in fact be that the two factors are interdependent and rely on each other. Support for this idea comes from an experiment that studied rats and found that those raised in a perceptually restricted environment had smaller brain development than those raised in an enriched environment, suggesting that while we are born with innate capabilities we need the environment to ensure we develop our abilities to perceive well. The perceptual capabilities we have at birth must be strengthened continuously through perceptual stimulation, furthermore, it would seem that perception in general follows the use it or lose it principle. Just as unused muscles become week, so to do our senses if left unused. Nature and nurture are both essential to health y perceptual development; stimulation begins in the womb and quickly follows all the way through adulthood. Sources. â€Å"Nature and Nurture in Perceptual Development. † . www. indiana. edu. Web. 11 Feb 2013. . . â€Å"Experiencing Sensation and Perception. † . physch. hanover. edu. Web. 11 Feb 2013. . Arterberry, M. â€Å"Perceptual Development. † . Colby College. Web. 11 Feb 2013. .

Physical, Intellectual, Emotional and Social Development...

Physical, Intellectual, Emotional and Social Development of Children Ages 0-8 Years Works Cited Not Included Physical development When the baby is picked up, the head falls backwards. This is because the neck muscles are not strong and developed enough to support the head. This is why the head always needs to be supported when the baby is lifted. When a newborn baby is held in a sitting position, they appear to roll up into a ball. The back curves over and the head falls forward because the muscles in the neck and back are not very strong. When a newborn baby is held upright with its feet on a flat surface,†¦show more content†¦At 3 months, the baby is starting to control its head. The baby still has to be supported when in a sitting position but the back is much straighter. Although the head is rather wobbly, they can hold it for a short while. When the baby is held in the standing position, the legs are beginning to be strong enough to take a little weight, though they tend to sag at the knee and hip. The hands are held open for most of the time now that the grasp reflex has gone. If the baby is given a rattle, they hold it for a few moments only. If the hand accidentally touches the clothes, the baby pulls on them. This is the stage when the baby spends a long time looking at its hands. Although still short sighted, the baby now has a greater focusing range and therefore can see further. There is also much more control over the movements of the eyes. The baby is very interested in looking at everything around them and is able to follow people who are moving nearby. At 6 months, the baby now has complete head control. There is no head lag and the baby is able to raise its head when lying on their back. When in a sitting position, the baby can hold its head upright and turn it to look around. The baby is now able to sit upright but still needs support from a chair or pram. They can also sit for a short while on the floor with its hands forward for support. At this age, theyShow MoreRelatedSummerise the Main Development of a Child from Age Range 0-2 Years, 3-5 Years and 5-8 Years1098 Words   |  5 PagesSummarise the main development of a child from the age range 0-2 years, 3-5 years and 5-8 years. Development refers to the process of learning new skills and abilities, and acquiring emotional maturity. All development changes are the result of both genetic and environmental factors. Genetic factors and diet are in the main responsible for growth, whereas environmental factors such as quality of the diet and disease are responsible for the emotional growth. ‘Child development’ is the term givenRead MoreThe Principles, Sequences And Stages Of A Child s Growth And Development1284 Words   |  6 Pageschild s growth and development. 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