200ml of water was then added to the filtrate in a 500ml beaker with constant stirring. White solid was formed in the process of addition and the solution was then left undisturbed in an ice bath for 10minutes. Once most of the solids had settled at the base of the beaker, the solution was decanted. 10ml of ethanol was added to the remaining suspension and was transferred in a clean centrifuge and centrifuged for 2minutes at 6000rpm. After the first centrifugation, the supernatant was discarded and the residue was washed by adding 14ml of ethanol.
After completion of the solubility tests, the appropriate solvent, cyclohexane, was selected for large-scale recrystallization. The unknown was weighed for the large-scale recrystallization then the same process was repeated to test the solubility. The solute dissolved after adding of about 60 mL of solvent, it was set aside to cool to induce crystal reformation. The solution was then seeded and set alone once more. When the process was complete, the crystals
14 vials were used for cotaining samples. When the distillation was proceeding at a moderate speed at about the wanted temperature, the receiver was replaced with a vial as the condensed vapour sample (V) and the thermometer was read. Half of the vial was filled with the sample. The stopper of the distillation flask was removed and using a dropper to collect the liquid. The sample was placed into appropriate vials as the liquid (L), and the vial was closed by the stopper.
The substitution reaction was successful but not fully effective. 19. If the data was inconclusive, then comparing various compounds and the unknown based on physical characteristics would be the first step, titrations would also be a good method. 20. To get a better yield, redoing the experiment would require careful attention in the recrystallization steps: amount of solvent used, how hot solvent is, if the mixture cools to room temperature before placing it in an ice
The sample was transferred to a 250 ml conical flask kept in water bath for alkali treatment. 75 ml of 17.5% caustic soda was measured using a measuring cylinder at 20°C. 15 ml of 17.5% NaOH was added and fibres were macerated gently with a flattened glass rod for 1 minute. 10 ml more NaOH was added and the solution was mixed for 45 seconds. 10 ml NaOH was again added and mixed for 15 seconds to make lump free slurry.
This melting point data confirms that isomerization occurred, since the melting point of dimethyl maleate is only -17℃, while the melting point of dimethyl fumarate is 102-105℃. This also highlights the fact that diastereomers have different chemical properties, such as melting point. Since the experimental melting point range almost overlaps with the expected range, there is little error in this measurement. The small amount of error could have occurred from the MelTemp temperature rising too quickly, leading to errors when reading the
22.5 g of plate count agar powder was dissolved in a litre of sterile distilled water on the hot plate 2. pH of the solution was adjusted to 7.0 ± 0.2 by adding NaOH or HCl and was immediately transferred into the Schott bottle to be autoclaved at 121 ° C for 15 minutes 3. Prepared medium was stored in 4° C chiller Lauryl Sulphate Broth
The supernatant was assayed for SOD activity by following the inhibition of epinephrine auto-oxidation. 0.5ml of sample was diluted with 0.5 ml of distilled water, to this 0.25 ml ethanol, 0.5 ml of chloroform (all reagents chilled) was added. The mixture was shaken for 1 min and centrifuged at 2000 rpm for 20 min. The enzymatic activity in supernatant was determined. To 0.05 ml of carbonate buffer (0.05 M, pH 10.2) and 0.5 ml of EDTA (0.49 M) was added.
Diazotized Sulphanilic Acid 1. Dissolve 1.1 g of anhydrous sodium carbonate in 50 mL of water in a 100 mL conical flask. 2. Add 4 g of sulphanilic acid to the solution and heat it until it dissolves. A small amount of suspended material may render the solution cloudy.
The correlation coefficient obtained with the Langmuir equation was high, which indicated a good fit between the parameters. The dimensionless parameter (RL = 1/(1+bCo)), which is a measure of adsorption favorability, was found to be in the range of 0.03105<1) and confirmed that Chromium(VI) removal using besharam plant at pH 2 and 320c was a favorable adsorption process. Table 6.5: Langmuir isotherm S.no Ce Ce