The charge transfer complex was studied from the reaction of iodine with mesitylene in pentane. From the relationship between concentration of iodine over its absorbance and concentration of mesitylene, the equilibrium constant was determined to be 0.4183, and the molar absorptivity to be 1.3780*104 M-1cm-1. Besides, the energy of photon needed to get excited was 369.52 kJ/mol, and the binding energy (W) of the excited state of charge transfer complex was 145.82 kJ/mol which was much larger than expected of only 9 kJ/mol for iodine and
Wittig reactions allow the generation of an alkene from the reaction between an aldehyde/ketone and a ylide (derived from phosphonium salt).The mechanism for the synthesis of trans-9-(2-phenylethenyl) anthracene first requires the formation of the phosphonium salt by the addition of triphenylphosphine and alkyl halide. The phosphonium halide is produced through the nucleophilic substitution of 1° and 2° alkyl halides and triphenylphosphine (the nucleophile and weak base) 4 An example is benzyltriphenylphosphonium chloride which was used in this experiment. The second step in the formation of the of the Wittig reagent which is primarily called a ylide and derived from a phosphonium halide. In the formation of the ylide, the phosphonium ion in benzyltriphenylphosphonium chloride is deprotonated by the base, sodium hydroxide to produce the ylide as shown in equation 1. The positive charge on the phosphorus atom is a strong EWG (electron-withdrawing group), which will trigger the adjacent carbon as a weak acid 5 Very strong bases are required for deprotonation such as an alkyl lithium however in this experiment 50% sodium hydroxide was used as reiterated. Lastly, the reaction between ylide and aldehyde/ketone produces an alkene.3
The complete experimental procedure is available in the General Chemistry Laboratory Manual for CSU Bakersfield, CHEM 213, pages 20-22, 24-25. Experimental data are recorded on the attached data pages.
Hydration of alkenes is characterized by the addition of water and an acid-catalyst to a carbon-carbon bond leading to an alcohol. Dehydration is exactly the opposite in which dehydration of an alcohol requires water to be removed from the reactant. Equilibrium is established between the two processes when the rate of the forward reaction equals the rate of the reverse reaction. The alkene that is used in this experiment is norbornene. Through hydration of norbornene, an alcohol group should be present on the final product yielded what is known as exo-norborneol. Percent yield is a numerical indication of how much of the reactant was actually reacted to yield product. The equation for percent yield is shown below:
Physical Chemistry Laboratory Manual, Physical Chemistry Laboratory, Department of Chemistry, University of Kentucky, Spring 2006.
The basic principle of the spectrophotometeric technique is the measurement of interaction between energy and electrons of the substance. Spectrophotometric technique is an analytical method used for estimating concentration of metal ion in liquid solution. One of the most magnificent effects of complex formation is the change of spectral properties. The reason for light absorption by complexes are as follows.
The metal Ni2+ and the ligand ethylenediamine (en) are studied in this experiment. Solutions are prepared with varying compositions of Ni(en)n2+. Using the equilibrium constants, it is possible to identify which species is present. If the constant for the formation of a species where n is 2 is larger than a species whose constant equals 3 then the former species is pre-dominant. Jobfs Method is limited in that it will give non-integral values of the n present if a fourth complex, ZLn+1, exists. If there is a large variation between the equilibrium constants then only two complexes will be present in the prepared solutions. The absorbance values are plotted, then the value of n can be calculated.
In 1945, the American Red Cross delivered 1550 parcels of food and other goods to a Japanese internment camp of 1450 people located in North China. The Japanese planned to disperse the packages equally among the people. Of the people in the camp, two hundred were American. Some of the Americans thought they deserved more since the parcels were from their country so the Japanese planned to divide the extra 100 parcels among them. However, many of the Americans were not satisfied and thought they deserved all of the parcels.
• The use of a catalyst will speed up the reaction as long as the catalysts electrode potentials are feasible for each step in the reaction. Since a catalyst lowers the activation energy and takes the reaction through a different route, according to the Maxwell-Boltzmann diagram, at a constant temperature more particles are able to react as demonstrated by the diagrams below:
All things, living or nonliving, consist of atoms and molecules. These particles are constantly in motion, and this continuous motion allows for the disbursement of molecules, or diffusion. The overall net movement of these molecules will go from areas of higher concentration, to areas of lower concentration. Therefore, following a concentration gradient (Martini). The rate of diffusion of these molecules, in accordance with Fick’s law of diffusion, is directly proportional to the concentration gradient present. However, the concentration gradient is not static and will change over time and with distance, therefore changing the rate of diffusion. It is hypothesized that the two solutions being tested, Methylene Blue and Potassium Permanganate, will begin their initial diffusion in the agar gel at a quick rate, and then progressively regress over the allotted time of 1 hour. Another factors other that will have an effect on rate of diffusion is molecular size. There is a substantial difference in molecular weight between Methylene Blue (320 g/mol) and Potassium Permanganate (158 g/mol). The combined molecules present in Potassium Permanganate are lighter than those in Methylene Blue, and therefore should allow it to diffuse more rapidly.
A radioisotope is an isotope that emits radiation as it has nuclear instability(Prostate Cancer; Fusion imaging helps target greater doses of radiation).Those who are not too familiar with radioisotopes may think their use is for harmful radiation, nuclear weapons, and the possibility of turning into a giant, raging, green monster. However, there are much more positive uses for radioisotopes. There have been many medical advances thanks to the benefit and practice of radioisotopes in nuclear medicine. These advances have been able to diagnose and treat a variety of diseases.
Thickett, Geoffrey. Chemistry 2: HSC course. N/A ed. Vol. 1. Milton: John Wiley & Sons Australia, 2006. 94-108. 1 vols. Print.
David and John Free. (26 Nov 2006). MadSci Network: Chemistry. Retrieved on March 6, 2011, from http://www.madsci.org/posts/archives/2007-02/1171045656.Ch.r.html
Individual atoms can emit and absorb radiation only at particular wavelengths equal to the changes between the energy levels in the atom. The spectrum of a given atom therefore consists of a series of emission or absorption lines. Inner atomic electrons g... ... middle of paper ... ... a sensitive multielement inorganic analyses.
Plontke, R. (2003, March 13). Chemnitz UT. TU Chemnitz: - Technische Universität Chemnitz. Retrieved April 1, 2014, from http://www.tu-chemnitz.de/en/