First, 50 mL of the sample was placed into a 250 mL Erlenmeyer flask, and onto a stirring plate. Then, the pH of the solution was measured and adjusted to be within the range of 4 and 6, using nitric acid and sodium hydroxide. After the pH was optimal for the experiment, a single mL of indicator- acidifier reagent was added to the sample. Then, 50 mL of mercuric nitrate was place into a burette and titrated with the sample until the color of the solution turned from blue to purple. The volume of titrant used for the reaction to reach endpoint was recorded.
Purpose: The purpose of this lab is to titrate an unknown solid acid (KH2PO4) with a standardized sodium hydroxide solution. After recording and plotting the data, the acid’s equivalence point will be recorded once the color changes. Using the equivalence point, the halfway point will be calculated, which is used to determine the acid’s equilibrium constant. The acid’s calculated equilibrium constant will be compared with the acid’s established pKa value. Eventually using the NaOH and the acid’s consumed moles, the equivalent mass will be determined.
This helps to indicate whether or not the reaction follows Markovnikov’s Rule, which states that the electrophile (E+) will add to the carbon involved in a double bond that produces the most stable carbocation. If the rule is followed, the reaction will proceed according to the mechanism in Figure 1. In the silver nitrate test, the alkyl bromide is added to AgNO3. The rate of precipitation with 2° should be faster than the solution with the 1° alkyl halide. In the sodium iodide test, the alkyl halide is added to sodium iodide in acetone.
Abstract: To determine the rate law in each reaction and find the reaction rate, an experiment was conducted with acetone, acid, iodine, and water. By using different concentrations of each substance, a number of 4 times, the rate was giving of each reaction and recorded the times it took to react. Based off the results from the first four reactions, further data was collect with a fifth reaction. Using 15mL of acetone, 10mL of hydrochloric acid, 5mL of iodine, and 20mL of water, we got a rate of 8.77× 10-7. The reaction rate was much higher than the rates of the previous reactions.
The buffer solutions were saved in case the electrode needed to be re-calibrated later on. The potassium acid phthalate solution was titrated with 0.1 M NaOH. The solution turned red when it reached the end point. The titration was continued for 10 seconds after a permanent red color was obtained. The volume of 0.1 M NaOH solution used was determined.
1 “substrate” and another “ enzyme.” Instead of using the distilled water, this time you are going to use different pH buffer in the enzyme test tube. In the substrate tube, add 7 mL of distilled water, 0.3 mL of hydrogen peroxide, and 0.2 mL of guaiacol for a total volume of 7.5 mL. For the enzyme tube, instead of distilled water add the pH solution (3) and 1.5 mL of peroxidase which equals a total volume of 7.5 mL. Use the dH2O syringe for our pH solution. To clean the syringe, flush it by drawing 6 mL of distilled water.
In Equation 1, for example, increasing the amount of hydrogen peroxide will increase the rate at which it reacts with iodide. The concentrations of iodide and acid remain the same, so the rate will depend only on the changes in hydrogen peroxide concentration. (The iodide is recycled between Equations 1 and 2, and the concentration of acid is high enough that the change in its concentration is small. Note the concentrations of the reactants in the Materials and Equipment section). The rate actually depends on the concentration of hydrogen peroxide raised to a power, called the "reaction order."
Some of the factors are thermometer was calibrated to determine its precision. The actual melting points of water, phenylacetic acid, o-anisic acid, and benzilic acid to their observed melting points were determined by calibrated thermometer. Then the solubility tests were run in order to determine the appropriate solvent for the unknown solute (Table 1). After determination of a solute, a vacuum filtration technique was used to determine the pure form of compound. The melting point of the purified sample was determined and compared to the melting points of other known compounds.