The purpose of this lab is to observe the changes in a chemical reaction and how factors affect the system like increase concentrations, temperature, pressure or common ions affect the outcome of the overall reaction and its equilibrium. The Le Chatelier’s Principle is used often in order to determine the direction of a reaction, like a balance when disturbed it shifts to more over to one side than the other; in this case if one side of the reaction is stressed the other side will react to counteract for the change. This often means that more or less products will form or reactants will be more present in the end. The five stages performed in this lab with varying chemicals each with stressed the system in various ways. The first reaction is that of 0.2M of cobalt dichloride and concentrated hydrochloric acid, the reaction produced cobalt tetrachloride and hydrogen gas or (CoCl2 + 2HCl = CoCl4 + H2) in which produced a royal blue or aqua marine color. Afterward, half of the contents of the test tube was poured into another and then was mixed with 7ml of water to produced pink Hexaaquacobolt(II), as such this equation is correct : ( CoCl4-2 + 6H2O = Co(H2O)6+2 + 2Cl2). This equation is reversible meaning if hydrochloric acid was mixed with Hexaaquacobolt(II) then the reaction would turn back to blue Cobalt tetrachloride and vice versa. The third test tube reacted with 0.1M AgNO3 or Silver nitrate to produce non-soluable Silver chloride, Cobalt(II) Nitrate and chlorine, the equation shows: (CoCl4 (aq)+ 2 AgNO3(aq) = Co(NO3)2(aq) + 4Cl(aq) + 2AgCl(aq) ). By adding silver Nitrate to the reaction, it removes a chlorine molecule from the equation and thus the reaction shifts to compensate for the lost chlorine molecule; it does that by doing a reverse reaction.
The second stage is a reaction in the change concentration of H+ ions in sodium hydroxide and hydrochloric acid. The stage called ten millimeters of water along with four drops of 0.6M hydrochloric acid in a beaker and same procedure as for the 0.6M sodium hydroxide. These diluted solutions were mixed with another solution containing 1ml of water, 4 drops of acid-base indicator and the diluted acid. The solution turns from orange to red because the indicator reacts to the change of hydrogen ion concentrations by changing color from orange to red. After that reaction, the diluted sodium hydroxide was added and the color of the solution returned to orange and this is because the ion OH- steals the proton from hydrogen, thus becomes water. The equilibrium equation is (HIn = H+ + In-) or (HOH = H+ +OH-), the ‘In’ indicates the indicator.
The third stage is the solubility of calcium hydroxide, which was created by using mixing calcium nitrate and sodium hydroxide; Ex: Ca(NO3)2 + 2NaOH = Ca(OH)2 + 2NaNO3. The calcium hydroxide separated to their individual ions when suspended into water and when the hydrochloric acid was added so the equation would be: Ca(OH)2(aq) ‘ …
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