In the round-bottom flask (100 mL), we placed p-aminobenzoic acid (1.2 g) and ethanol (12 mL). We swirled the mixture until the solid dissolved completely. We used Pasteur pipet to add concentrated sulfuric acid (1.0 mL) to the flask. We added boiling stone and assembled the reflux. Then, we did reflux for 75 minutes.
Experimental Procedure A dry, empty freezing-point tube and its cork were weighed together. Carefully, 15-20g of pre-cooled cyclohexane was poured into the freezing-point tube, the tube recorked, and the whole thing was reweighed, to find the exact mass of the cyclohexane. The dry thermistor and stirrer were inserted into the FP tube, ensuring they were immersed in the liquid. A large beaker was filled with ice and water, which the FP tube was placed into. The cooling curve was determined by recording the temperature at regular time intervals (every fifteen seconds) as the cyclohexane cooled, until the temperature became constant.
Once this point was reached, the timer was stopped and the time was recorded in Data Table #1. The same steps involving the addition of Na2S2O3 were repeated for Wells #2 and #3, using 2 mL of Na2S2O3 in each. The final times for each well was recorded in Data Table #1 in the appropriate blank. Once the first trial was completed for the first three experiments, a second trial was completed in Wells #4, #5, and #6 using the same procedure in order to increase accuracy. After each trial was conducted, each of the wells were emptied into the designated waste container and dried using a paper
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.
This was repeated until no more gas was released. Next, the funnel was suspended through a ring, and 10 ml of 5% sodium hydroxide was added. When the two layers were separated in the separatory funnel, the aqueous layer was identified. The two layers were then separated into two different beakers. The water layer was acidified by adding concentrated hydrochloric
After all data was collected, the equation M1V1= M2V2 was used to determine the initial concentrations of each reagent in each run. [Note: The final volume (V2) for each run was 11.0 mL or 0.011 L]. Used the volumes and given molarity concentrations illustrated in Table 1 for M1 and V1. Below, Table 2 shows the finished initial concentrations for each reagent in each of the four
Once we finished this, we then repeated steps (a-d) to measure and record the rock 's volume. Next, we proceeded to the next set of steps in exercise 2. Before completing the next steps, we obtained a pipette with a bulb, a 100-ml beaker, and a 10-ml graduated cylinder. Once obtaining our materials, we were then ready to complete the steps. First, we removed some water from the graduated cylinder.
Then an estimated (by trial and error) 1-3 grams of hydrated copper sulfate was added to a crucible with the lid on top. The total mass of the hydrated copper sulfate was recorded by subtracting the total mass of the crucible, lid, and sample from the mass of the crucible and lid (described in table 1.3). By attaching the wire triangle to the ring, the crucible was able to sit securely while having the bunsen burner underneath. Lighting the burner once again, each substance was heated for several minutes until estimated that the compound had changed color. Once a prevalent color change had been observed at approximately 4 minutes (blue green color) the crucible was set on the counter using the tongs to cool for approximately 5 minutes.
This process was repeated 10 times. Data The data from Table 1 was gathered by calculating the pK_a and K_a of the unknown weak acid using the change in volume and pH of the solution. The table contains data for trial number, starting and final volume, change in volume, pH of the solution, pK_a of the solution, and K_a of the
The slides were placed for 2 hrs at 4 °C in a lysis buffer containing (2.5 mol/L NaCl, 100 mmol/L Na2EDTA, 10 mmol/L Tris, [pH 10] and a freshly prepared 1% Triton X-100 and 10% Dimethyl sulfoxide were added to the buffer just before use). Next, slides were covered and incubated for 20 min at 4 °C with electrophoresis alkaline buffer containing (300 mmol/L NaOH, 1 mmol/L Na2EDTA [pH > 13]) in the electrophoresis chamber. This step allowed DNA unwinding and the expression of alkali-labile DNA damage sites. Electrophoresis was performed for 30 min at 25 V and 300 mA. DNA from undamaged cells did not migrate and appeared circular while, DNA from damaged cells migrated to the anode and appeared as a comet.
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.
First, the 250-mL graduated cylinder, 100-mL graduated cylinder, and the 10-mL graduated cylinder were observed to see the volume of the liquid in each one. Then, one digit further was estimated, and the results were recorded. After that, the 25-mL graduated cylinder and the 50-mL beaker were cleaned and dried. Next, their masses were measured on the scale, and the results were rounded to the nearest thousands decimal place. Subsequently, the Erlenmeyer flask was filled with 100 mL of distilled water.
Place C Elegans into the plates with the E Coli and leave for 24 hours. Examine the C Elegans to insure that the C Elegans have survived at the room temperature and continue to have multiple C Elegans surviving. Once this is done prepare the dilutions of all the subjects which we are testing. Start with 1% solution for Nitrate-N 100ml and move 10ml of the first well into the next. Fill the well with 90ml dh20 to reach 100ml.