The goal of this experiment is to prepare a photosensitive solution and explore its properties. While analyzing the solution, one will learn how to successfully handle these sensitive chemicals and then establish its properties via spectrophotometry.
Introduction1
During this experiment, a ferrioxalate solution will be produced from a solution of ferric nitrate that is reacted with oxalic acid. In order to become and oxalate ion, the oxalic acid can donate up to two protons. Ferrioxalate, or tris(oxalate)ferrate(III), is the product of three oxalate ions on Fe(III), as seen in the figure below2:
Ferrioxalate as an ion can undergo a photochemical reaction if it is exposed to light which results in the rather unstable complex of diaquabis(oxalate)ferrate(II) ion. There is no visible change when the reaction occurs since both the reactants and products are colourless. The second solution, potassium ferricyanide, will be prepared and used to test the extent of the photochemical reaction by adding it to the first solution, ferrioxalate. The ferrioxalate solution will be tested with different colours and exposure times of light. We will also establish what colours of light it absorbs by using spectrophotometry. When exposed to light the ferrioxalate solution will undergo a reaction and produce diaquabis(oxalate)ferrate(II) ion. Adding the ferricyanide solution allows us to see the changes that are occurring. The ferricyanide reacts with the Fe2+ of the photo-reacted product,
• • Find the value of the equilibrium constant for formation of FeSCN2+ by using the visible light absorption of the complex ion. Confirm the stoichiometry of the reaction.
After placing in darkness the colorless solution resulted by reformation of the radical intermediates to a new thermodynamic product via C-N bond at room temperature. UV-Vis was conducted on the solution before and after the irradiation with sunlight: UVtoluene 554.92nm, A=0.12 before irradiation and A=1.05 after. The peak at 554.92nm corresponds to yellow/green light and its complementary colour is red/violet. This validates the solutions violet color. The increased absorbance was accounted for an increase in the radical component. The radical was formed when exposed to light, which was visually apparent with the purple coloration and proved the thermodynamic dimer was also photochromic. When dimer 4 is exposed to light photons collide with the molecule and impart energy upon them. This energy is significant enough to break the bond between the two rings and results
When the red Co(NO3)2*6H2O crystal was added to the white NH4 crystal, and water was added to dissolve, the solution turned blue in color. As the solution was nixed, the color changed to that of a blue-purple and a blue precipitate formed. When the 6 M NH3 began to be added, the color shifted to dark purple color after 15 mL of ammonia and the amount of the precipitate was less. After 20 mL of ammonia, the solution became a red brown with very little of the blue precipitate. After 30 mL of ammonia, the solution was similar in color to an iodine solution, a dark brown-red, almost black in color. At this point there was no visible precipitate on the surface of the solution. After 40 mL of the ammonia had been added, the solution was the same iodine like color as before. When closely examined, there was a black precipitate that had settled on the bottom of the beaker. At this point, hydrogen peroxide, 3% H2O2, was added to solution. After 4 mL of the H2O2 was added, the solution was the same color and the precipitate had not changes. After 8 mL of the H2O2, there was not noticeable change. After 12 mL of the H2O2, the solution was slightly redder in color but the precipitate had not changed. After 15 mL of H2O2, the solution was the same color and no changes had occurred to the precipitate. At 17 mL, the solution began to effervesce slightly, though there
Part 1: Obtain some 0.200M Fe(NO3)3 solution and some 0.00020M KSCN solution. Starting from the first solution, pour and mix 8.0mL of Fe(NO3)3 solution and 2.0mL of KSCN solution into a test tube, where as the second solution has 7.0mL of Fe(NO3)3 solution and 3.0mL of KSCN solution. Continue this process until 5 test tubes have been filled. Pour
Table 2: Addition of KSCN, Fe(NO₃)₃and Na₂HPO₄to Iron (III) Thiocyanate and Change of Direction of Equilibrium
The powdered cobalt oxalate hydrate was weighed to about 0.3 g and placed in a pre-weighed crucible. The crucible and the cobalt oxalate were then heated until the cobalt oxalate decomposed into a stable, black solid, or Co3O4. Once the crucible was sufficiently
The first reaction involves pyrite rock reacting with oxygen (air) and water to produce dissolved ferrous iron, sulfate, and acidity. The second reaction oxidizes the dissolved ferrous iron in acidic conditions and produces ferric iron and water. The third reaction involves the hydrolysis of the ferric iron to form ferric hydroxide and more acid. The ferric hydroxide is the orangey-red colored solid you see in the water (Juniata College).
Dissolve 2.34 g of cobalt chloride hexahydrate (CoCl2.6H2O) in 100 ml of water in an Erlenmeyer flask. While stirring the oxalic acid solution constantly, add the cobalt chloride solution drop by drop. Let the mixture cool in an ice bath. A precipitate will form slowly.
This entry was posted in Research papers and tagged UV Spectroscopy research paper, UV Spectroscopy research proposal on May 19, 2013.
This experiment initially involved the synthesis of an iron (III) oxalate complex with the general
Since we now have determined the two different colors of Cobalt, we can now find constant K. With the help of the spectrophotometer, the absorbance of the stock solutions were measured at 656nm and 519nm respectively. The concentration was determined with the help of Beers Law and the extinction coefficient of each wavelength. Finally, the equilibrium constant was .327x10^-7.
Of Exp #5: In this experiment we will learn about the spectroscope and how it works. To learn the concept of quantitative measurements, to construct a spectroscope and, to use it for taking quantitative measurements.
Dissolve the corresponding salt mostly nitrate in desired amount in double distilled water. Dissolve pure Salicylic Acid (20%) in Methanol in another beaker and Quinolin (80%) in minimum Acetic Acid in the third one. Prepare separate solution of NaOH by dissolving NaOH pellets in double distilled water in the fourth beaker. Add solution of Quinolin (80%) to Salicylic Acid (20%) solution and then add NaOH solution to the mixed solutions. The solution of NaOH is needed to maintain basicity in the solution (i.e pH >7). Precipitate is obtained which was then filtered with the help of filter paper. The filtrate was dried under the lamp for several hours to drive away the moisture and used for photoluminescence measurements. Photoluminescence measurements
Part B of the experiment determines the absorbance and maximum wavelength of the eight standard solutions. Part C of the experiment determined the light absorbance of six Kool-Aid samples using the calculated average maximum wavelengths of Red 40 and Blue 1 from Part B. With the data, the concentrations of Red 40 and Blue 1 can be determined in each of the six Kool-Aid samples by using the Beer-Lambert law (A= εlc). Molar absorptivity (ε) can be calculated using the slope from the calibration curve of the absorptivity and concentrations of the two dyes from Part A and B and the path length of the cell was 1 cm
Fe3+ before the oxalate ion will readily bind to it. Hydrogen peroxide is the oxidant of choice: 2Fe2+ (aq) + H2O2 (l) + 2H+ (aq) ---> 2Fe3+ (aq) + 2H2O (l), in acidic solution.