.40g of NaH_2PO_4, and .40g of Na_2HPO_4 was measured into a 150 mL beaker. 50mL of distilled water was then measured in to a graduated cylinder and added to the 150ml solution of NaH_2PO_4 and Na_2HPO_4. 20 drops of the .04% Bromothymol blue solution was then also added to the buffer solution. After adding the 20 drops the tint of the liquid changed to a light green. The Vernier pH probe was calibrated and used to determine the pH of the phosphate buffer solution which was 6.81.
Materials and Methods To first create the three distinct solutions, 50mL of phosphate buffer with a pH of 6.84 was poured into a 150mL beaker with 20 drops of 0.04% Bromothymol blue indicator. 5mL of the solution was then added to three separate 50mL beakers. 1mL of HCl was added to one of the three beakers and labeled ‘Yellow’, 1mL of NaOH was added to another and labeled ‘Blue’, and 1mL of distilled water was added to the last beaker and called ‘Green’. The spectrometer was prepared and left to warm up before calibrating it. Taking the three solutions prepared earlier, each was transferred to three separate cuvette while filling the fourth cuvette was filled with distilled water.
A flame test was then conducted and the identity of the cation was determined. To determine the anion, the anion had to be separated first from the cation in the unknown compound. To do this, 0.1 grams of the unknown compound and 0.5 grams of sodium carbonate had to be boiled in 5 mL of distilled water. Once the solution boiled for 10 minutes, the precipitate was centrifuged out and the anion solution was left. 0.1 M silver nitrate was added to the anion solution and a precipitate was formed.
Use the pipet to place 10ml of water into an empty test tube 3. Place two drops of red dye into the test tube 4. Place one drop of yellow dye into the test tube 5. Compare the controlled color to the new color 1. Repeat steps one and two 2.
First, 0.4040 grams of NaH2PO4 and 0.3989 grams of Na2HPO4 were added to a 150 mL beaker, along with 50 mL of distilled water. Next, 20 drops of bromothymol blue were inserted into the solution. The program LoggerPro and a Vernier pH probe were used to calculate the pH. Then, a volumetric flask was used to measure 5 mL of the buffer solution into each of three, separate 50 mL beakers. After rinsing a volumetric pipet with 1.0 M HCl, 1.00 mL of 1.0 M HCl was transferred to one of the three beakers.
Using a burette, run 5.0 cm3 of 0.100 mol dm-3 peroxodisulphate solution into a 100 cm3 beaker. Add 45 cm3 of distilled water, from a burette, stir gently to mix. 2. Using burettes, measure out 15 cm3 of each of the 0.500 mol dm-3 potassium iodide, 3 cm3 of 0.010 mol dm-3 sodium thiosulphate solutions and 2.0 cm3 of starch solution into the second 100 cm3 beaker. 3.
Courtney Sever Period 2 10/11/12 Experiment 3: Beer’s Law Purpose/Hypothesis: The reason we prefer to express the law with this equation is because absorption if directly proportional to the other parameters as long as the law is obeyed. In this experiment we are going to test different solutions and then test an unknown. Materials: CBL Colorimeter Test tubes (6( Test tube rack 8 Cuvettes Pipets Gatorade (unknown) Blue Stock solution Water Beakers Paper Towels Procedures: * Turn on the CBL, and open the apps to the Colorimeter setting. * Fill one cuvette with water, making sure the outside is completely dry, and set in the colorimeter to calibrate it. * Then label each test tube, 1-6.
Each organic extract is then dried over anhydrous calcium chloride pellets and evaporated to dryness. The extract is then wet with a minimal amount of dichloromethane and a sample of each is obtained and mixed together with 200 mg of alumina and again evaporated to dryness. This mixture is then placed in the prepared chromatography column and eluted with hexanes until the yellow β-carotene band is collected. The solvent is then switched to a 90/10 mix of hexanes and acetone to speed up the elution of the more polar lycopene band, which is also collected in its own flask. Each of these samples is evaporated to dryness and rehydrated with a minimal amount of dichloromethane.
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.
Mix using a plastic pipette. f After 10 seconds, use the plastic pipette to place one drop of the mixture on the first drop of iodine. The iodine solution should turn blue-black. Squirt the rest of the solution in the pipette back into the test tube. g Wait another 10 seconds.