The solution was discarded into the waste bin, and the materials were washed. The second reaction in Part B, sodium hydroxide and ammonium chloride, began by saving the data from the first reaction and setting up the LabQuest to new data collection under the same conditions as the first reaction. The cups were restacked and placed in the beaker. Using a graduated cylinder, 50mL 2M NaOH was added to the cup. The cup was then covered and the temperature probe inserted.
We then slowly added 25ml of chilled deionised water to the filtrate to initiate crystallization by using a measuring cylinder and a dropping pipette, once we had done this we left it for about 10 minutes to allow crystallization at room temperature. We then weighed a filter paper which we will use later in the experiment. We then collected the crystallized acetylsalicylic acid by vacuum filtration in a Buchner funnel and washed the product with a little ice-cold water. We then pre-weighed a clean, empty watch glass and labelled it with our initials and the date, we did this do we could easily identify that it was ours when we go to weigh it with the crystals on. We
* In the above RB, a calculated amount of 1.2 equivalent amount of PTSH was added during continous stirring. * To the RB a condenser was attached and it was put on refluxing for a time period of 18 hours at a temperature of 80 degrees in an oil bath. * Post refluxing, the condenser was removed and it was left undisturbed for 1 day and then cooled to a temperature of -20 degrees by keeping in the freezer for setting of hydrazone crystals. * Once the crystals were formed, the supernatant was decanted and the crystals were transferred to a beaker where they were washed with cold methanol and then dried. * These dried hydrazone crystals were used in the subsequent steps.
Water was removed from the dish, and the Cu was then washed thrice with 5 mL deionized water, and decanted between washings. It was then similarly washed thrice with 5 mL of ethanol. The evaporating dish was then placed on the steam bath to dry until the Cu had a sand-like texture. The bottom of the dish was dried, it was cooled to room temperature, and then its mass was measured and recorded. All the solutions were disposed of in the liquid waste container, the Cu and Al were disposed of in the solid waste container, and the apparatus was cleaned and put
I. Introduction This experiment uses calorimetry to measure the specific heat of a metal. Calorimetry is used to observe and measure heat flow between two substances. The heat flow is measured as it travels from a higher temperature to a lower one. Specific heat is an amount of heat required to raise the temperature of one gram of anything one degree Celsius.
5 mL of 3M sodium hydroxide, 5 mL of de-ionized water, and 15 mL of hexane were added to the reaction flask and stirred. The mixture was transferred to a separatory funnel, separated into an organic layer and water layer, and then drained. The water layer was washed twice with 10 mL of hexane. The organic layer was dried
The mixture was finally made upto 5 mL with distilled water and placed in hot water bath at 95ºC for 1 h. After cooling, 1 mL of distilled water and 5 mL of the mixture of n-butanol and pyridine (15:1, v/v) was added. The mixture was vortexed and after centrifugation at 4000 rpm for 10 minutes, the absorbance of the organic layer (upper layer) was measured in UV-Vis spectrophotometer (Shimatzu) at 532 nm against blank using distilled water. TBA when allowed to react with MDA aerobically formed a colored complex [MDA-(TBA) 2 complex] which was measured with spectrophotometer. MDA concentration (measured as TBARS) was calculated as
5-aminotetrazole monohydrate: In a 250 ml round-bottom flask equipped with a condenser for refluxing (90 °C) and a magnetic stirring bar, 5.00 g (5.95 mmol) dicyandiamide (three times crystallized), 7.47 g (11.9 mmol) sodium azide and 11.00 g (17.8 mmol) boric acid and 100 ml of water is added and allowed to reflux for 24 hours, after the completion of the reaction, until the solution pH to about 2 to 3 as hydrochloric acid 37% is added (about 12 ml) Then the reaction mixture was cooled in a refrigerator for 18 hours and the white crystals formed. The mixture was filtered and washed three times with 10 ml of water and and dried in 60 °C for 5 hours and finally 45.8 g of product by it will be obtained. 5-Aminotetrazol monohydrate: Yield:,
The washings are filtered off into a 100 mL measuring flask; after cooling distilled water is added until the mark is reached (stock solution). In proportion to the expected chloride content aliquot part of this solution, which should preferably contain 50 mg – 100 mg NaCl, taken off, distilled water being added to obtain a quantity of approximately 100 mL. Subsequently 5 mL ferric alum solution, 20 mL 0.1 N AgNO3 solution and 5 mL – 10 mL ether or 1 mL nitrobenzene are added; titration is carried out by means of an ammonium thiocyanate solution 0.1 N, until the red colouring remains after
SDS-Polyacrylamide gels were prepared and the glass plates were washed with 70% ethanol and water. After drying the plates, water was used for test leakages. Two SDS-Polyacrylamide gels were prepared according to the following recipe. These all above components of the running gel were added in a 50 ml tube and solutions were mixed and pipetted into the prepared gel chambers. Glass plates were filled ¾ and the gel was covered with 100-500 µl Isopropanol in order to achieve an even surface.
Methanol was filled in a test tube and placed into a water bath to heat up. 12 Drops of the Methanol were then added to each flask until the crude caffeine had completely dissolved. 13. The solution was then filtered and the residue collected in a filter paper. It was left to dry and
The first consists to heat a sample to liberate the water hydration, and then compare two mass weights before and after heating so gets easier to find the water percentage (mass). Second step consists in chemical processes with the sample that drives to determine the percentage of the other element. Materials and chemical
Subsequently, the Erlenmeyer flask was filled with 100 mL of distilled water. Using the thermometer, the temperature was measured and recorded. Then, the 25-mL graduated cylinder was filled with 25 mL of distilled water, and its mass was measured and recorded. The density of the water was found using the temperature and the Density of water index. Moreover, the calculated volume of water was calculated using the formula of density, and the difference between observed volume and calculated volume was found.
While swirling the phosphoric acid solution in the Erlenmeyer flask, the sodium hydroxide solution was added to it a few drops at a time using a disposable plastic pipette. The After all the sodium hydroxide was transferred, the flask was rinsed with 2 mL of deionized water and added to the flask with the reaction mixture and swirled for an additional minute. A clean, dry evaporating dish with a watch glass was then weighed and recorded to 0.001 g. The reaction mixture was then transferred to the evaporating dish. The flask was then rinsed with 2 mL of deionized water and added to the evaporating dish containing the reaction mixture.
The silver ion TLC was prepared through the following procedure: Silver nitrate was dissolved in 10 ml of distilled water. This aqueous solution of silver nitrate was absolutely mixed with 9 g of silica gel (10 ~ 40 μm particles). Then, a 10 × 5 cm TLC plate was coated with the above slurry and activated for 1 h at 90 °C before use. They were immediately transferred into a desiccator in dark for storage after cooling. 32 100 μL of afore-prepared sample solution and the mixed reference standard were diluted 100 times with ethyl acetate.