Identification of an Unknown Organic Acid Essay

We know that that the end point of the titration is reached when, after drop after careful drop of NaOH, the solution in the flask retains its pale pink color while swirling for about 30

1. To titrate a hydrochloric acid solution of “unknown” concentration with standardized 0.5M sodium hydroxide.

pH was recorded every time 1.00 mL of NaOH was added to beaker. When the amount of NaOH added to the beaker was about 5.00 mL away from the expected end point, NaOH was added very slowly. Approximately 0.20 mL of NaOH was added until the pH made a jump. The pH was recorded until it reached ~12. This was repeated two more times. The pKa of each trial are determined using the graphs made on excel.

In 2 and 7 I added 50 mL of .1 M NaCl. I added sodium acetate to the rest of the beakers: 1 gram to 3 and 8, 5 grams to 4 and 9, and 10 grams to 5 and 10. I then filled the beakers that contained the solid sodium acetate with 50 ml of .10 M acetic acid. Specifics can be found on page 84 of the lab manual. Though the lab manual instructed to use a pipet, we did not have an accurate 1 mL pipet or a graduated pipet, so we instead prepared two graduated burets with 1 M Sodium Hydroxide and 1 M hydrochloric acid. Using a standardized pH probe with a Lab Pro to measure changes in pH, we added 1 mL of HCl at a time and recorded the changes. The same was done for the NaOH.

mL cylinder to the beaker on the stir plate and empty it into the beaker. Place the pH probe in the beaker and record the pH in the data table. Drag the beaker to the red disposal bucket. Double-click the bottle of NaHCO3 to move it to the Stockroom counter. Repeat steps 5 and 6 for KNO3.

7. Using the slider on the right hand side, add NaOH to the HCl in the Erlenmeyer flask (This action is known as titrate). Add the indicator until the color of the indicator turns a light shade of pink.

We can know from the unknown melting point table that this acid is o-Toluic because o-Toluic melting point is (103-105) °C. This was coming from NaOH extraction, which we added 10% HCl to make it acidic and recovered the acid. The crystalized form of NaOH was still wet when doing the measurement, so that make the temperature a little bit higher than theoretical melting point. Even that, it was left for a week to dry but the recovered acid was accumulated over each other, and can feel it was still wet when taking the acid in pipette to measure the melting

By first measuring the pH levels of solution A through E with a pH meter, it gives a numeric reading to ph balance to a solution. Next, add in a natural indicator called anthocyanin made from the pigment from a red cabbage into each solution and mixed it until there is a distinct color and recorded on the chart. Finally, by looking at the result of the pH reading level that

The solution has been dechlorinated and adjusted to be slightly acidic. Place 75 mL of the solution in each of three labeled beakers. Obtain an animal organism, small fish, and a plant organism, Elodea. One beaker will be the control and will not have anything in it. Place exactly 25 mL of water in a 50-mL graduated cylinder. Place each organism in a cylinder and note the increase in volume above the original 25mL. The increase equals the volume of the organism. After taking measurement, cover each beaker with the plastic film. Place the beaker containing the Elodea in the dark by covering it with aluminum foil. Allow organisms to respire for 15 min. Gently remove the organisms from the beakers and return them to their original culture bowls. Then add four drops of phenolphthalein to the contents of each beaker. The solutions should remain clear because the solutions are acidic. Using a dropper bottle, dispense NaOH into the contents of the beaker drop by drop. Thoroughly mix the contents of the beaker after adding each drop. Continue adding drops until you first notice that the solution turns pink. Repeat for each beaker with at the living organism until the solution is the same shade of pink as the

Approximately 3.4 grams of K2HPO4 was weighed on a triple beam balance and dissolved in 100.00 mL of DI water by diluting to the mark in a volumetric flask. Similarly, 2.4 grams of NaHPO4 was weighed on triple beam balance and dissolved in 100.00 mL of DI water by diluting to the mark in a volumetric flask.

During a titration the pH of the solution will be monitored using a pH meter from that we get a titration curve. The titration curve is then used to determine the equivalent molecular weight and Ka value of the unknown weak acid, from that we are

The guiding question of this ADI lab was, “What are the identities of the unknown compounds?” The goal of this lab was to understand the relationships between moles and molar mass to find the identity of unknown compounds. The mole can be used to measure small amounts of a substance or is used to convert from unit to unit using dimensional analysis. One mole is equivalent to the molar mass in grams of that substance. If you start with the moles of an unknown substance, multiply it by a given compound’s molar mass, and then divide it by however many moles are in the compound of your choice, you will get the mass of the compound. With that answer you can then compare with mass of the compound in the bag to determine its identity. We first started

One milliliter of 6.00-M phosphoric acid was placed into a 125-mL Erlenmeyer flask using a volumetric pipette. Using a slightly larger pipette, six milliliters of 3.00-M sodium hydroxide was transferred into a 50-mL beaker. Then a disposable pipette was used to slowly mix the sodium hydroxide into the phosphoric acid while the solution was swirled around. Then both the beaker and flask were rinsed with 2-mL of deionized water and set aside. A clean and dry evaporating dish was weighed with watch glass on a scale. Then the solution was poured into the dish and the watch glass was placed on top. The solution was then heated with a Bunsen burner to allow for the water to boil off to reveal a dry white solid. After the dish cooled to room temperature it was once again weighed and the new mass was recorded.

In this lab a acid-base indicator phenolphthalein was used to determine endpoint of a reaction HCl(aq) and KOH(aq). At the end point all of the HCl(aq) would have reacted with KOH(aq), and the pH becomes 7. The phenolphthalein would changed colours from colourless to pink indication when enough KOH(aq) was added. The purpose of numerous trials was to use the average volume of the 3 trials with similar measurements.

For this experiment, a pH meter was used so this part of the experiment began with the calibration of the pH meter with specified buffers. The buret was then filled with the standard HCl solution and a set-up for titration was prepared. 200g of the carbonate-bicarbonate solid sample was weighed and dissolved in 100 mL of distilled water. The sample solution was then transferred into a 250-ml volumetric flask and was diluted to the 250-mL mark. The flask was inverted several times for uniform mixing. A 50-mL aliquot of the sample solution was measured and placed unto a beaker. 3 drops of the phenolphthalein indicator was added to the solution in the beaker. The electrode of the pH meter was then immersed in the beaker and the solution containing the carbonate-bicarbonate mixture was titrated with the standard HCl solution to the phenolphthalein endpoint. Readings of the pH were taken at an interval of 0.5 mL addition of the titrant. After the first endpoint is obtained, 3 drops of the methyl orange was added to the same solution and was titrated with the standard acid until the formation of an orange-colored solution. Readings of the pH were also taken at 0.5 mL addition of the titrant.