Colorimetric Determination for the Composition and Equilibrium Constant For the Formation of a Metal Complex Ion Abstract The object of this experiment was to determine properties for the formation of a metal complex ion, ferrothiocyanate by observing its colorimetric characteristics. The reaction was done for differing amounts of Fe+3 and SCN-, and the absorbance was measured using a spectrophotometer. The absorbance showed that maximum Fe(SCN)+2 ion production was achieved when the mole fraction of SCN was .6, which was close to the expected value of .5. However, when the equilibrium constant was calculated for this reaction, experimental error may have played a role when the achieved value of -660 was significantly different than an expected large positive number. These properties of equilibrium were determined through colorimetric properties. Introduction Colorimetric properties of certain chemical compounds can be used to determine many characteristics of the reaction itself. In this experiment, colorimetric determination was used to find the equilibrium constant for the formation of the Fe(SCN)+2 ion, noted by the equation Fe3+(aq) + SCN- (aq) Fe(SCN)+2 Many chemical reactions such as this reaction are never fully completed in the sense that all the reactants will completely react to form the products. There exists a state known as equilibrium, in which neither the forward reaction nor the reverse reaction is performing. The equilibrium constant, K, is a measurement of the ratio of the concentrations of the reactants to products at which equilibrium is reached- the reaction will neither proceed in the forward nor reverse direction. In this experiment, the equilibrium constant is K= [Fe(SCN)+2] / [Fe... ... middle of paper ... ...esents itself that the actual experiment can’t be completed. If the equilibrium constant were to be calculated accurately, this could be used to calculate concentrations of various products or reactants. This experiment was completed with minor deviations from the original protocol. A slight mistake was made when solutions were transported from the test tube to the cuvette. The funnel wasn’t rinsed out completely, and this may have led to slight deviations. However, it may not have been enough to make a significant impact upon the results. Overall, this experiment went as planned. The equilibrium constant for this reaction was calculated, as well as finding the mole fraction at which this reaction would produce the most significant reaction. Even though some calculations weren’t as expected, this reaction was completed and made sense from a superficial view.
Then the reaction tube was capped but not tightly. The tube then was placed in a sand bath reflux to heat it until a brown color was formed. Then the tube was taken out of the sand bath and allowed to cool to room temperature. Then the tube was shaken until a formation of a white solid at the bottom of the tube. After formation of the white solid, diphenyl ether (2 mL) was added to the solution and heated until the white solid was completely dissolved in the solution. After heating, the tube was cooled to room temperature. Then toluene (2 mL) was added to the solution. The tube was then placed in an ice bath. Then the solution was filtered via vacuum filtration, and there was a formation of a white solid. Then the product was dried and weighed. The Final product was hexaphenylbenzene (0.094 g, 0.176 mmol,
Objective: The objective of the experiment is to determine what factors cause a change in speed of a reaction. It is also to decide if the change is correlated with the balanced equation of the reaction and, therefore, predictable. To obtain a reaction, permanganate, MnO_4^(1-), must be reduced by oxalic acid, C_2 O_4 H_2. The balanced equation for the reaction is:
...form 〖PbCrO〗_4 and then process it through a filter. After filtering the 〖PbCrO〗_4 I had to dry the 〖PbCrO〗_4 residue in the drying oven for 30 minutes at 80℃. Then let it cool for 5 minutes and weigh it and finally make a few calculations to obtain the theoretical, actual, and percent yields of 〖PbCrO〗_4. I was able to fulfill the experiment because I obtained all the answers to the equations in an accurate amount. I believe this experiment was a success due to my hypothesis of, If physical methods are used to separate 〖 PbCrO〗_4 precipitate from the reaction mixture then I can successfully calculate the theoretical, actual, and percent yields, being correct.
This paper describes the methods used in the identification, investigation of properties, and synthesis of an unknown compound. The compound was identified as calcium nitrate by a variety of tests. When the compound was received, it was already known to be one of twelve possible ionic compounds. The flame test identified the presence of the calcium anion in the compound. The compound tested positive for the nitrate cation using the iron sulfate test. At this point it was hypothesized that the compound was calcium nitrate. Reactivity tests and quantitative analysis comparing the unknown compound with calcium nitrate supported this hypothesis. Synthesis reactions were then carried out and analyzed.
John O. Edwards; Kathleen Edwards; Jorge Palma; The reactions of ferroin complexes. A color-to-colorless freshman kinetic experiment 1975, 52, 408
In our experiment we utilized the hydrate cobaltous chloride. Hydrates are crystalline compounds in which one or more molecules of water are combined with each unit of a salt. Cobalt (II) chloride hexahydrate is an inorganic compound which is a deep rose color in its hydrated form. As an inducer of
Abstract: This week we experimentally determined the rate constant k for the reaction 2HCl (aq) +Na2S2O3 (aq) → S (s) + SO2 (aq) + H2O (l) + 2NaCl (aq). In order to do this the average reaction time was recorded in seconds during two trials. The data from the experiment shows this reaction is in the first order overall: rate=.47s-1 [HCl]0 [Na2S2O3]1. These findings seem to be consistent with the expected results
What were we trying to accomplish with this experiment? What method did we implement to accomplish the task? What techniques were used to purify and identify the product(s) of the reaction?
4. The reason why the position of the equilibrium was unaffected in this reaction because of reaction:
One of the key results of the experiment was that the percent yield was greater than 107%. Often times, the actual yield is less than the theoretical yield because there may be competing reactions, external conditions may not be ideally maintained, or the reactants are not pure. However, in this experiment, the actual yield was higher than the theoretical yield possibly due to the source of errors that dust accumulated on the precipitate or some of the precipitate reacted with other elements in the atmosphere. Another key result of the experiment was that the data indicated that the reaction involved 〖Fe〗^(2+)ions because the calculated Cu/Fe molar ratio was approximately 1.07, or rounded to 1:1. This mole ratio is closer and similar to the first equation Fe(s)+〖CuSO〗_4 (aq)→〖FeSO〗_4 (aq)+Cu(s), because the Cu/Fe molar ratio is also 1:1. Therefore, the reaction with 〖Fe〗^(3+)ions did not take place since its equation – equation 2 – has a Cu/Fe molar ratio of
The presence of a colored precipitate represents a pattern in the electron configuration of cations. When the outer p orbital of the ion of the metal is full, the precipitate of the product is white and no other color is present. When the outer d orbital of an ion is not completely full, the precipitate of the product is a true color. When the d orbital is completely full, the color of the precipitate is not a true color. Magnesium sulfate, aluminum chloride, and calcium chloride had a white precipitate after reacting with sodium hydroxide. Sodium chloride remained a clear liquid. The ions of magnesium, aluminum, calcium, and sodium have complete outer p orbitals and have no d orbitals. The precipitates and/or the liquids were colorless because
The purpose of the experiment is to study the rate of reaction through varying of concentrations of a catalyst or temperatures with a constant pH, and through the data obtained the rate law, constants, and activation energies can be experimentally determined. The rate law determines how the speed of a reaction occurs thus allowing the study of the overall mechanism formation in reactions. In the general form of the rate law it is A + B C or r=k[A]x[B]y. The rate of reaction can be affected by the concentration such as A and B in the previous equation, order of reactions, and the rate constant with each species in an overall chemical reaction. As a result, the rate law must be determined experimentally. In general, in a multi-step reac...
Varying the n value carries out the experiment. Absorbencies of each of the ZLn complexes are obtained. The sum of the concentrations of the metal, Z, and the ligand, L, are kept equal. With the ratio of the ligand to the metal in the solution with the maximum absorbance for the ZLn complex, the value of n can be determined as well as the composition of ZLn.
This is the first reaction in the Harcourt Essen experiment. The iodine is oxidised to produce I2 wh...
The aim of this experiment was to investigate the affect of the use of a catalyst and temperature on the rate of reaction while keeping all the other factors that affect the reaction rate constant.