Environmental chemistry

Experiment 1 and 2 Recrystallization: Purification of Solids and Melting points Purpose: In the fist experiment, impure Vanillin was purified through the process of recrystallization. Desired solutes were recovered through the technique of vacuum filtration, and then dried to take percent recovery In the second experiment, a percent recovery of the recrystallized Vanillin from the first experiment was performed. The percent recovery of Vanillin was 77.18% A mixed…

According to R.A Aitken, “An asymmetric synthesis may be defined as a synthesis in which an achiral unit is an ensemble of substrate molecules is converted to a chiral unit such that the possible stereoisomers are formed in unequal amounts.” It relates to any synthetic process that incorporates one or more new elements of chirality during a functional group transformation. Asymmetric synthesis involves the formation of chiral molecules. An object is said to be chiral, if it cannot be…

TRIS Hcl, NBT, NADH, Ethanol, PMS, l-ascorbic acid 1. The superoxide radicals is generated in 3 ml of TrisHCl buffer (16 mM, pH 8.0) containing 1 ml of NBT (50 μM), 1 ml NADH (78 μM) and ethanol extract of sample (25 – 50 μg). 2. The reaction was started by adding 1 ml of PMS solution (10 μM) to the mixture. 3. The reaction mixture was incubated at 25° C for 5 min, the absorbance was read at 560 nm using a spectrophotometer (Schimadzu UV-Vis 1700) against blank samples using l- ascorbic acid…

the temperature, most OMCVD processes which are operated thermally occur at 300~800℃ and this is still much higher than the room temperature[9]. Secondly, the organic exhaust gas is usually hazard and toxic to human healthy and can be serious environmental problem without proper treatment. Thirdly, as the goal of the OMCVD process, to produce zero-valent state of metal element with existing technology and producing units is only possible for the Ni(CO)4. The processes which apply other…

Salts and molecules have similar characteristics, and many differences whether we can tell by first looks or not. Testing these two only supports the differences, and many structural functions cause these differences. Since salts are ionically bonded, they have different properties and functions compared to the covalent bonded molecules. Salts have a ionic bond, and we can confirm due to their electronegativity. As you move from left to right on the periodic table you would notice that…

The unique composition and purity of as-deposited SnS2 thin films prepared with different precursor solution volumes from 5 ml to 25ml were determined by EDX analysis as shown in fig 5, which brought out the presence of Tin and Sulfur as elementary components. Two different peaks were observed in the spectrums from fig 5 relevant to the tin and sulfur. The EDX spectra show that the weight percentage for the film prepared at the precursor solution volume of 5 ml is 36.8% and 63.2%, which is…

Table 1: Experimental data for standardization of iodine solution. Calculation of standardization factor Standardization factor = (mass of vitamin C titrated) / (Volume of iodine solution used) = (125g) / (41.3ml) = 3.03 mg vitamin C/ml iodine solution Experiment B: Vitamin C titration using fresh fruit sample to determine the content The tabulated experimental data for this experiment is shown below (Table 2). In this experiment, the amount of vitamin C was calculated by multiplying…

Background : Stoichiometry is the relationship between the relative quantities of substances taking part in a reaction or forming a compound, typically a ratio of whole integers. In the lab that I did with my group we used stoichiometry to find out the decomposition of sodium biocarbonate. Sodium carbonate is just another name for baking soda, and that is what we used on our lab. Baking soda is also used in some food items, such as pancakes, waffles etc… When the baking soda is being heated…

Magnesium Alloy: Microstructure Characteristics: Fig (8) : Shows the microstructure of Magnesium alloy. Picture source: http://www.omicsonline.org/JMSTimages/2155-9589-2-114-g001.html Magnesium alloys have a hexagonal lattice structure. They are the lightest of all structural metals. Magnesium alloys possess a low galling tendency as a bearing surface in conjunction with shaft hardness above 400…

Results The results obtained were statistically analyzed using the Fishers exact test. Table 1: Comparison of microbial growth between different groups Sodium Hypochloride Total Fishers exact test Endovac Laser Control p-value No Growth 5(50.0%) 8(80.0%) 0 15(37.5%) <0.001* <103 5(50.0%) 2(20.0%) 0 7(17.5%) 103 – 108 0 0 0 8(20.0%) >108 0 0 10(100.0%) 10(25.0%) Total 10 10 10 40(100.0%) *p<0.05 statistically significant p>0.05 non significant, NS Amongst the 10…