When transferring the acid from the mortar to the flask by washing it with water, the low solubility of the acid made it hard and some of it was still stuck in the mortar and was not transferred into the flask. When phenolphthalein was added to the unknown acid solution, the solution remained clear.
At first, when the Noah base was added to the unknown acid solution, the solution where the base had dropped into changed into a pink color which disappeared after swirling the flask containing the unknown acid, which returns to being clear.However, after more Noah base was deed to the unknown acid solution, the solution eventually turned pink after swirling the flask. Data processing: As we did not refill the burette with Noah each time after titrating the unknown acid, we need to calculate the difference of the volume before and after each tire.
For example, the volume used in the first tire would be calculated by: 25-21. 3=3. 7 ml Uncertainty: (Uncertainty of the previous volume + uncertainty of volume after titration) = (0. 05+0. 05) -O. Ml Calculating the rest of the titers in a similar fashion (previous volume-volume after titration) the following table of results is obtained: Table 3: Table of the illume of 0. 201 mold-3 sodium hydroxide (Noah) used to titrate ml (В±O.
Ml) of unknown acid X in ml (В±0. 1 ml) for each tire. Amount used to tire ml (В±O. Ml) of unknown acid X in ml (В±0. Ml) First tire 3. 7 3. 2 3. 0 Let HEX be the acid X, then the equation of the naturalization of the acid would be: HEX + Noah CLC H2O + Max So the ratio of HEX to Noah is .
The first value, 3. Ml, is a pilot and is disregarded in the calculations, so we are left with 3 concordant values within 0. Ml of each other. Since the number of moles-concentration*volume, we need to find out the average value of the illume obtained: (Titrate 1+ Titrate 2 + Titrate 3)/3 +3. 0+3.
2)/3 =3. Ml (Largest value-smallest value)/2 Average volume of titrate: 3. 1 ml В± 0. 1 (% uncertainty of concentration+% uncertainty of volume) Since the ratio is 1:1, then the moles of the unknown acid HEX is also 6.
231*AAA-4. Then there are 6. 31 *IOWA-4 moles of HEX in ml of XX solution, then the concentration is: Number of moles / volume -6. 231 mold-3 (% uncertainty of number of moles + % uncertainty of volume) Then, with the concentration, we can find the number of moles of acid HEX originally added to the mall of water: Number of moles= concentration * volume -2.
924*AAA-3 moles. (% uncertainty of concentration+% uncertainty of volumetric flask) =(3. 84… % +0. 1/100) -3.
94… % Molar mass=mass/number of moles =603. Egg/mol (% uncertainty of mass + uncertainty of number of moles) -24. Final obtained molar mass of unknown acid HEX is egg/molВ±20 Conclusion: The obtained value for the monophonic acid is egg/mom В±20 so it falls within the range of between gambol-1 to gizmo-1. The unknown acid is benzene acid, or COACH with a molar mass of 122.
121. My result was strongly deviant from the expected the result with a percentage difference of MY obtained result was much larger than the actual value of the molar mass of benzene acid, COACH. The large percentage difference means that my experiment was not accurate.
This meant that there were major systematic errors that greatly influenced the accuracy of the results.One of which was the fact that benzene acid was actually insoluble, which defeats the aim of the experiment, which was “To determine the molar mass of a soluble organic acid..
. “. However, the low accuse. Also, the large percentage difference meant that there were not only random errors, but a large systematic error in the procedure of the experiment which would be discussed in the evaluation.
EVALUATIONS Limitations Effects Solutions The chosen acid, benzene acid, had a poor solubility in cold water and most of the acid was filtered from the solution.Most of the acid was not dissolved in the water. This caused an artificially higher mass by which we divided the concentration of the solution to obtain the molar mass, which, as a result, was also as a result was artificially large. Choose another soluble acid with which to carry out the experiment in determining the molar mass Or add enough water to the undisclosed benzene acid. Or heat the solution until all the benzene acid is dissolved at benzene acid is lobule at high temperatures.It was hard to actually determine at which point the acid was neutralized Too much base may have been added Use a probe and data logger to accurately and precisely track the change in the pH throughout the titration. Not all the benzene acid was transferred into the flask from the mortar We would have assumed an artificially higher mass by which we divided the concentration of the solution to obtain the molar mass of the benzene acid, which was artificially large as a result.
Wash the mortar with distilled water several times more after most of the acid had been transferred into the flask.