Write this down when you start the titration. Next, you must determine the volume of the solution delivered to reach the equivalence point. Next, you will find the moles of base used in the titration: *Note that the volume of base is in L, not in mL Determine number of moles of HCl in flask: If you write the balanced reaction for the neutralization of sodium hydroxide and hydrochloric acid, you will see that the reaction proceeds in a 1:1 fashion. That is, for every hydroxide (OH‐) ion added, it can neutralize exactly one hydronium (H+) ion. This is not always the case for neutralization reactions, and is thus not always the case for acid‐base titrations.
8- Repeat step( 6 ). 9- Wash the ester layer with 6 ml saturated sodium chloride , shake and allow two layers to separate . At this point ,The ester layer should not be cloudy . Again discard lower layer. 10- Transfer the ester layer to a small dry test tube and dry the ester with anhydrous CaCl2 and stir for 10 min.
The mixture was finally made upto 5 mL with distilled water and placed in hot water bath at 95ºC for 1 h. After cooling, 1 mL of distilled water and 5 mL of the mixture of n-butanol and pyridine (15:1, v/v) was added. The mixture was vortexed and after centrifugation at 4000 rpm for 10 minutes, the absorbance of the organic layer (upper layer) was measured in UV-Vis spectrophotometer (Shimatzu) at 532 nm against blank using distilled water. TBA when allowed to react with MDA aerobically formed a colored complex [MDA-(TBA) 2 complex] which was measured with spectrophotometer. MDA concentration (measured as TBARS) was calculated as
The volumetric flask was then filled up to its 100 mL mark with deionized water. The buret was washed out with dionized water and then with the strong base NaOH before being filled up with NaOH. About 20 mL of the unknown weak acid was pipetted into a beaker. The starting volume of the NaOH in the buret was recorded before about 4 mL of the strong base was titrated into the weak acid solution. The final volume was recorded.
E. Discussion: In order to synthesize the polymer, Nylon 6,10, we had to complete a few steps to create the chemical reaction that combined sebacoyl chloride and hexamethylenediamine. First we measured the mass of the two graduated cylinders when they were empty, and measured it again after they were filled with sebacoyl chloride and hexamethylenediamine. We did this in order to find the measurements of the reactants. When we measured the graduated cylinder when they were emptied, one weighed at 10.99 grams while the other weighed at 10.94 grams. Even though they were the same kind of cylinder, I believe that a systematic error might have caused the second cylinder’s weight to be slightly affected, causing the weight to be lowered by 0.05 grams.
The KHP and the acid samples must be dried, because there would still be extra water which would skew the molarity. The calculated molarity of the NaOH would be lower because there would be extra volume in the solution, but still the same amount of moles of NaOH, so the molarity would be less, and thus, will require more titrant in order to
In this experiment, 293 mg of aldehyde was weighted for method 1 instead of 250 mg and. Although .7906 mg of phosphonium salt was added, this probably was not enough to complete the reaction. The only significant change throughout method was 1 was that the yellowish mixture became slightly lighter. However, it was found that after vacuum filtration, there was some white and yellow
Methylene chloride was added to the TLC chamber until it reaches 0.5 cm depth in order to cover the bottom of the jar; a piece of filter paper was added to the jar allowing the solvent to travel up the paper and the surface area of the solvent increased. Then the plate was placed in the jar containing 100% CH2Cl2 so that the top of the plate rested against the side of the jar opposite the filter paper. When the eluent was near to the top of TLC plate, the plate was removed and then
50 µl of prepared extract was added at 2 mg/ml to Tube 1 a-c ( 100 µg of overall extract). 38 µl of prepared extract was added to Tube 2 a-c (75 µg of overall extract). 25 µl of prepared extract was added to Tube 3 a-c (total of 25 µg of extract). 50 µl of methanol only was added to tube 5 which is the negative
To have gotten a 0% error between the experimental and actual value for CH3COOH, the pH would have been measured at about 4.75, which is slightly more acidic than 4.80. The percent error was calculated to determine how accurate the Ka of acetic acid was: Since the calculations yielded a 20% error, this shows that experimental error occurred during the experiment. Factors that could have affected the results included improper reading of the meniscus for volume of NaOH, not allowing the NaOH to fully drip into the buret after removing the funnel, adding too much acetic acid after the indicator flashed pink to get an inaccurate equivalence point, and not allowing the solution in the beaker to mix thoroughly to get an accurate reading from the pH