A standard curve plotted during the analysis was used to extrapolate the concentration of iron in the urine samples (Sandell and Kolthoff, 1937). Reagents and Chemicals- Potassium iodate, Ammonium persulphate, Ceric ammonium sulfate, Arsenic trioxide, Sodium chloride, conc. Sulphuric acid and distilled water. Quantitative method based on
The powder on the filter paper could've fell and this caused it to have a smaller percent purity, percent yield and also cause a lower absorbance and concentration of pure ASA. Another error would be not using a properly dried sample for the pure ASA in part C when making the crystals, this could have cause tye percent yield error. This would make a lower melting point. To prevent this from occurring next time there could be a dry sample that is completely dry and this would not alter the mass of the sample and this would make the solution have a more
TLC was used to identify the actual unknown product as well as other products/reactants present in the filtered solution. The procedure was conducted by placing a TLC plate in a developing chamber that is filled with a small amount of solvent. The solvent cannot be too polar because it will cause spotted compounds on the TLC plate to rise up too fast, while a very non-polar solvent will not allow the spots to move. The polarity of the spots also determines how far it moves on the plate; non-polar spots are higher than polar ones. After spots on the TLC form, the Rf values are calculated and used to analyze the similarity of the compounds.
Exercise 1 1. Suppose a household product label says it contains sodium hydrogen carbonate (sodium bicarbonate). Using your results from Data Table 1 as a guide, how would you test this material for the presence of sodium bicarbonate? B BoldI ItalicsU Underline Bulleted list Numbered list Superscript Subscript33 Words If I had a household product labeled sodium bicarbonate, I would add an acidic substance and expect bubble to be created. As we know acid reacts with bubbles when combined with sodium bicarbonate.
One error that could have affected the percent yield is not filtering out all of the liquid from the filter paper in the funnel before setting it off to dry. This would have increased the final mass of the solid, not making it accurate. To stop this from happening again, the liquid could be drained more thoroughly until it fully stops dripping into the Erlenmeyer flask. Another error that could have affected the percent yield is the amount of trials performed. This would have made the results less accurate and made any errors change the final results even more.
Formula 2: % Component= 100% component mass (g) sample mass (g) Procedure First, we measured out the evaporating dish to find the mass. Then we added around 3 grams of our sample (2.832g exactly). Next we added the isopropyl alcohol to dissolve the Benzoic Acid. We filled the evaporating dish, stirred, and then decanted the sample into a 140mL beaker with a stirring rod. This
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.
The aim of this experiment was to prepare a buffer for an unknown amino acid with the goal of identifying the unknown amino acid. The objective was to use the Henderson Hasselbalch equation to determine the buffer capacity, and to use the pKa values and molecular weight, to identify the unknown amino acid through acid-base titrations. Titration was done on the unknown amino acid with a strong acid and base while titration was done on NaCl, which acted as a blank for identifying the unknown amino acid and was used to find the true titration curve of the amino acid. The pka values were found to be 1.95 and 8.88, and the molecular weight 133.98 g/mol. Moles extrapolated from the titration curve were used to find the molecular weight of the unknown amino acid, along with the pkas and the pI.
In addition, phenolphthalein was added as an indicator. The aliquots were titrated against sodium hydroxide (NaOH) solution until end point was reached, after which volume of NaOH consumed was recorded. The value of the rate constant, k, obtained was 0.0002 s-1. The experiment was then repeated with 40/60 V/V isopropanol/water mixture and a larger value of k = 0.0007 s-1 was obtained. We concluded that the rate of hydrolysis of (CH3)3CCl is directly proportional to water content in the solvent mixture.