Spectrophotometry Essay

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Spectrophotometry is a method in which organic and inorganic substances are identified or characterized by the use of electromagnetic radiation. Electromagnetic radiation not only includes light (or photons), but thermal energy as well. While the electromagnetic spectrum consists of wavelengths between gamma radiation and the Far IR, most spectrophotometric methods rely on the UV and visible region. In order to use spectrophotometric methods, the sample being analyzed must be able to absorb the energy (photon) used to excite the sample. UV-Vis and other optical instruments measure the transition of energy from the ground state to the excited state, or the release of energy as the molecule returns to the ground state. The energy is often released …show more content…
The concentration made was determined to be 0.0009946 M of Fe3+. The acid was made from diluting 41.3 mL of concentrated HCl in a 500 mL volumetric flask. Due to the large amounts of samples and standards, the acid solution was made multiple times.
Saturated Potassium Thiocyanate Saturated potassium thiocyanate was made in 100 ml volumetric batches. The solution was made from continuous addition of potassium thiocyanate to the flask until it stopped to dissolve in the solution. Since each batch of saturated solution contains different amounts of thiocyanate, sample sets were blanked with the corresponding thiocyanate solutions.
Time Duration For the time duration and wavelength determination, 5 mL of iron standard and 3 mL of saturated thiocyanate was mixed and diluted to 100 mL in a volumetric flask with 0.5 M HCl. The absorbance was read over a period of 2 hours at 30 min intervals.
Excess Reagent Standard iron solution was used and 0.5 M potassium thiocyanate was prepared. Following the reagent table below, the corresponding amounts of each reagent was added to 100 mL volumetric flask and diluted with water. The samples were analyzed with water as the

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