The Composition Of Complex Ions In Solutions

The Composition Of Complex Ions In SolutionsIn this experiment, we are required to determine the composition of confused ion by uninterrupted variation method. Complex ions refer to a metal cation bonded to either genius or more than one molecules. It is a stepwise process to levy the complex ion because every process has its own equilibrium constant (Gretchen E. Potts,2001). However, straight variation method involves the continue changing of the different engrossment of the solution. also that, spectrophotometric method seat be used to quantitatively identify the noncitizen composition or concentration of a savour solution with par to a take with known concentration. Then, spectrophotometer refers to an instrument which we can use it to gradation the catch fire intensity. As we know, most of the UV-Vis spectrophotometers have a range of the wavelength amid 190nm-1100nm. This range lies between UV and Visible lightness region. (Frans F,2004)In this instrument, it has 2 light sources. D2 and W lamp are used for UV and Visible light respectively. It bequeath ensure that only monochromous light will track down through the slit. Reference cuvette is used as a blank. At the annihilate we can get the reading from the detector.Furthermore, Beer Lambert law states that when a monochromatic radioactivity passes through a transparent solution, the intensity of the absorbed radiation is directly proportional to the concentration (c) and the optical pathlength, (l) of the solution. So, Absorbance, A = x l x c , where is the molar absorptivity.The materials we used during the experiment are ammonium ion adjure (III) sulphate and Salicylic bitter. Therefore, we used the following method to determine the concentration of the iron (III) salicylic sexually transmitted disease complexes.Materials and Methods 500 cm3 of Ammonium iron 500 cm3 of salicylic acid solution(III) sulphate solution was prepared. was prepared.Optical density of the other have s were refractory using the same instrument and wavelength.The most suitable wavelength for measuring was determined.These salmagundi was then measured using spectrometer over the range of 350-700nm.cuvetteResults From the spectrum, the upper limit peak has a wavelength of 531.5 nm.With the same wavelength, we obtained the following Absorbance for different samples and the data was put down in the following table.Discussion From the results above, the molecular ratio of the Fe3+- salicylic acid complex by using Jobs method was 11. The complex is formed by which the salicylic acid donated its lone pair electrons from hydroxyl oxygen atom to iron metal. This is because, salicylic acid is a bidentate to the metal ion. Therefore, it needed three salicylic acid to donate its lone pair electrons to the iron(III) ion. So, the complex formed is trisalicylateferrate(III). The structure will be drawn as follow In this experiment, we measured the absorbance of our samples from UV-Vis spect rometer. The sample was poured into a cuvette. The sample was not destroy which means that with the using of this spectrometer, the sample was non- destructive. The UV- Vis light pass through the cuvette and the light was absorbed by the sample. Therefore, the sample must be in liquid form.Besides that, before flux of Fe3+ and salicylic acid, the two solutions were colourless. However, after mixing the two solutions, the sample had a violet in colour. So, they can absorb visible light and because of the electrons from d orbital was excited from one to another electronic state. The complex gave violet in colour is because it absorbed green light and let the other light passed through. Green light is a complementary colour to the violet light, so the complex gives the upper limit absorbance at wavelength 531.5 nm.In addition, we normally will pick out the maximum absorbance is because its sensitivity to the concentration of the solution is the greatest at the maximum wavelength. If the max is not the analytical wavelength, strong radiation may be strongly absorbed and caused deviation from the Beer Lambert Law. However, in this experiment, if let asseverate we did not use themax, the result we obtained from graph will not be affected much. We will also need to round off it to integer so that we can get the ratio.Furthermore, stoichiometry formula of a complex ion can be obtained through continuous variation method. Besides that, this method is actually help in the maintaining the number of moles of the sample throughout a series of different mixture in the sample. However, only different is the mole subdivision of the different samples.Conclusion The maximum peak for iron(III)-salicylic acid complex was 531.5 nm.The molecular ratio of the Fe3+- salicylic acid complex is 1 1