25 ml of diluted unknown acid solution to 100ml beaker by using 25 volumetric pipet. 10ml of deionized water and 3 drops of phenlpthalin indicator the beaker labeled as 3. Potentiometric titration acid solutions 125 ml of NaOH was obtaining in a beaker and 50 ml of NaOH transfer to buret the tip and the meniscus is at below 0 ml. one magnetic stirring bar placed in a beaker contain one of the known solution on a stir. The pH recorded by using pH electrode before adding NaOH.
Volume Measurements See Figure 1 for the sketch of our meniscus in our 25 mL plastic graduated cylinder with 12.5 mL of tap water in it. We filled a small glass test tube with tap water, poured it into the graduated cylinder, and the volume recorded was 22.5 mL. We determined the volume of the thin-stemmed micropipette by filling the micropipette with tap water and counting the drops as they fell into the graduated cylinder. We counted 34
The mixture was decanted again in to the same beaker. Next, we added boiling chips to the liquid and evaporated the solvent over the hot plates under the hood. After the solvent was evaporated and the flask was cooled, we used a spatula to remove a small amount of the crude product and took its melting point. We determined the melting point range of the sample to be 43.0-46.0 degrees Celcius.The crude product was yellow colored when it was warm and orange in color when cooled and sticky. We then recrystallized our sample using 5 ml of warm acetone that was heated on a hot plate under a hood.
Using a pipet, transfer the methylene chloride solution to a 50 mL Erlenmeyer flask. To this solution, add a scoop of anhydrous sodium sulfate (Na2SO4), in order to remove the last traces of water. 10. While the solution is drying, weigh (tare) a 50 mL beaker to the nearest 0.001 g on a balance. Record this tare weight in Table 1 on the DATA SHEET.
Then, no more than 20 drops of 15M NH4OH were added dropwise until colored complex or a precipitate was formed. An additional 10 drops of 15M NH4OH were added to the solution. To conduct the confirmation flame test, 20 drops of each metal solution were added to the corresponding labeled centrifuge tubes. After setting up the Bunsen burner and adjusting the flame, the Nichrome loop was dipped in concentrated HCl and then placed above the inner blue cone in the flame until no
The normality of the unknown base is calculated after the solution has reached the end point. The amount of substance being delivered is calculated in units of equivalents per litre using the formula: VaNa = VbNb Experimental In order to titrate the acid with the unknown base, a solution of the acid was prepared. 5.1722 (±10%)g of potassium hydrogen phthalate acid is obtained using a weighing boat and transferred into a volumetric flask containing 250mL of boiled distilled water. Volumetric flask was shaken several times in order to assist the powder to dissolve. Once dissolved, 24.9734 (± 0.0045)mL of acid was pipetted into an Erlenmeyer flask along with 25mL of cool (recently boiled) distilled water.
The 15 M NH4OH was added drop wise until a color change occurred, or until 20 drops were added. An additional 10 drops of 15 M NH4OH were then added to each solution. Again, 5 centrifuge tubes were labeled for the same 5 cations and 20 drops of each solution were added to the appropriate centrifuge. HCl was also added to a 50 mL beaker. The Nichrome wire loop was dipped in the HCl solution and placed over the Bunsen burner to disinfect it.
Test tubes were labeled before being put into the climate. One in a freezer at about -20 degrees Celsius, One in a refrigerator at about 4 degrees Celsius, One in a water bath at about 20 degrees Celsius, One in a water bath at about 45 degrees Celsius, One in a water bath at about 60 degrees Celsius, and One in a water bath at about 70 degrees Celsius. Leaving each test tube in the specified climate for 20 minutes. 5. After the treatment period was over 10mL of distilled water (room temp) was added to each test tube.
50 mL of this buffer solution were then obtained and twenty drops of .04% bromothymol blue solution were then added turning the overall color of the solution green. Three 50 mL beakers were then gathered and filled with 5.00mL of this green solution. Each of the beakers were then added 1mL of either 1.0 M HCl, 1.0 M NaOH, or distilled water. The beaker that was added HCl was labeled yellow, the one with NaOH was labeled blue, and the one with distilled water was labeled green. The final color of each solution corresponded with it’s label.
A melting point will be ran on the aspirin when completely dry. A capillary tube containing the dry aspirin will be placed into the melting-point apparatus. This process is to determine the melting point range of aspirin. First, a hot water bath was created with a 400. mL beaker on a hot plate. The temperature was raised to 70 degrees Celsius and 4.419 g of salicylic acid was measured out on a balance and transferred into a 125. mL Erlenmeyer flask.