Chemistry Acid-Base Titration

Chemistry unbendable Acid and Weak Base Titration Lab Cherno Okafor Mr. Huang SCH4U7 November 21st, 2012 Data assembly and touch density of the streamer HCl solution 0. 1 M Data Collection effort 1 mental testing 2 runnel 3 closing HCl Buret Reading 0. 05 mL 38. 3 45 54. 5 initial HCl Buret Reading 0. 05 mL 29. 9 38. 3 45 book of account of NaHCO3 employ 0. 1 mL 9. 2 9. 5 9. 8 qualitative Data I used the methyl chromatic power which was desirable for my titration because of its clear and distinct influence tack from orange to a beadlike blushful at the conclusion * At the beginning of the titration after I added 3 drops of methyl orange into the imbruted (NaHCO3) and swirled, I began titrating the sharp (HCl) s pocket-sizedly, and initi altogethery in the methyl orange and foundation garment, in that location was a niggling total of inflamed food colouring present, but then it quickly disappeared due to skimpy HCl (H+ ions)then I gradually kept titra ting more dit while swirling and there was even more red colour present, until finally I reached the endpoint when the orange-yellow colour had completely transformed into a red colour * Changes from an orange-yellow colour (slightly higher pH 4. 4) to a bright red colour (at low pH 3. 1) at the endpoint and point of equivalence * Baking sparkling pissing (NaHCO3) absorbed the odour caused by the strong acid of HCl when I heterogeneous the two bleach-like smell ProcessingIf the niggardliness of an acid or base is uttered in molarity, then the volume of the solution compute by its tightfistedness is equal to the moles of the acid or base. because, the following relationship holds nVb x Cb = Va x Ca Where Vb = the volume of the base Cb = the immersion of the base Va = the volume of the acid Ca = the concentration of the acid n = the mole factor In the case of hydrochloric acid and Sodium Bicarbonate (Baking Soda), the mole ratio is unity to one, thus the mole factor is 1. Th erefore, the volume of atomic number 11 bicarbonate multiplied by its concentration in molarity is equal to the moles sodium bicarbonate. The moles of sodium hydroxide are equal to the number of moles of hydrochloric acid in the reaction.The neutralisation equation becomes HCl + NaHCO3 NaCl + H2O + CO3 Hence, Cb = Va x Ca / Vb. running 1 numeration * First we need to find the counterchange of volume of the acid used up in the titration Va = Vfinal Vintial Va = 38. 3 0. 05 29. 9 0. 05 Va = 8. 4 0. 1 mL Therefore, nVb x Cb = Va x Ca (1)(9. 2 0. 1)(Cb) = (8. 4 0. 1) (0. 1 0. 0005) Cb = (8. 4 0. 1) (0. 1 0. 0005) / (9. 2 0. 1) Cb = (8. 4 1. 19%) (0. 1 0. 5%) / (9. 2 1. 09%) Cb = (0. 84 1. 69%) / (9. 2 1. 09%) Cb = 0. 0913 2. 78% 0. 0913 0. 00254M is the concentration of the base for run 1Theoretical Base compactness = 0. 1 0. 0005 M Experimental Base preoccupancy = 0. 0913 0. 00254 M Trial 2 Calculation * First find change of volume of the acid used up in the titration Va = Vfinal Vinitial Va = 45 0. 05 36 0. 05 Va = 9. 0 0. 1 mL Therefore, nVb x Cb = Va x Ca (1)(9. 5 0. 1)(Cb) = (9. 0 0. 1) (0. 1 0. 0005) Cb = (9. 0 0. 1) (0. 1 0. 0005) / (9. 5 0. 1) Cb = (9. 0 1. 1%) (0. 1 0. 5%) / (9. 5 1. 05%) Cb = (0. 9 1. 6%) / (9. 5 1. 05%) Cb = 0. 0947 2. 65% 0. 0947 0. 00251M is the concentration of the base for endeavor 2 Theoretical Base Concentration = 0. 1 0. 005 M Experimental Base Concentration = 0. 0947 0. 00251 M Trial 3 Calculation * First find change of volume of the acid used up in the titration Va = Vfinal Vinitial Va = 54. 5 0. 05 45 0. 05 Va = 9. 5 0. 1 mL Therefore, nVb x Cb = Va x Ca (1)(9. 8 0. 1)(Cb) = (9. 5 0. 1) (0. 1 0. 0005) Cb = (9. 5 0. 1) (0. 1 0. 0005) / (9. 8 0. 1) Cb = (9. 5 1. 05%) (0. 1 0. 5%) / (9. 8 1. 02%) Cb = (0. 95 1. 55%) / (9. 8 1. 02%) Cb = 0. 0969 2. 57% 0. 0969 0. 00250M is the concentration of the base for trial 3 Theoretical Base Concentration = 0. 1 0. 0005 MExp erimental Base Concentration = 0. 0969 0. 00250 M * Now, I will average all 3 trials Trial 1 0. 0913 2. 78% 2. 78% / 100% x 0. 0913 = 0. 0913 0. 00254 M Trial 2 0. 0947 2. 65% 2. 65% / 100% x 0. 0947 = 0. 0947 0. 00251 M Trial 3 0. 0969 2. 57% 2. 57% / 100% x 0. 0969 = 0. 0969 0. 00250 M Therefore (0. 0913 + 0. 0947 + 0. 0969) (0. 00254 + 0. 00251 + 0. 00250) / 3 trials = (0. 2829 0. 00755) / 3 = (0. 0943 0. 00252) MAverage Concentration of base for the 3 trials * Percentage defect = Theoretical Actual / Theoretical x 100% = (0. 1 0. 0005) (0. 0943 0. 00252) / (0. 1 0. 0005) x 100% = 0. 0057 0. 00302 / 0. 1 0. 0005) x 100% = (0. 57 0. 00352) x 100% = 5. 7% 0. 00352 Conclusion and valuation Conclusion In this titration lab, I used a strong acid HCl (hydrochloric acid) vs. a weak base NaHCO3 (sodium bicarbonate/baking soda). My intent was to find the concentration of the weak base after it has been titrated with the strong acid. The notional basic solution had a concentration of 0. 1 0. 0005 M. In my experiment, the value I obtained was 0. 0943 0. 00252 M, which is pretty close to 0. 1. I also had a very small error percentage at just 5. 7% 0. 00352 error. My experimental value was only off by 0. 0057 (0. 1- 0. 0943) with a total uncertainty of 0. 00402 (0. 005 + 0. 00352) from the theoretical value of the base concentration. Evaluation/Improvement Some of the most notable errors in my procedure to attend are the small quantities being used and hence the inaccuracy in mea sure enoughments. perhaps I could have arranged the titration to have bigger titres, which would reduce errors by using larger quantities such as a higher concentration for the standardized solution. In addition, there was also some splattering/ want of the acidic solution being titrated into the basic solution, as it came into contact with the edges and turn up of the flask, which in turn, presumably initiated errors in volume measurements.Also, this means that not all of the acid that was added reacted efficiently with the basic solution mixed with methyl orange indicator. Moreover, there could have been impurities in the basic solution itself and as swell as the indicator causing a higher reading than the theoretical value of concentration. The leakage that resulted from the stock cock may have caused the HCl to substitute slightly in content because of the reaction with some of the chemicals in the remote environment (air). There was also some residue that could have been unexpended behind in the basic flask when I washed it with distilled water after the neutralization of each trial. Perhaps drying it could have made a difference instead of leaving it wet.Maybe some of the neutralized solution was go away behind after I washed stunned the flask, and it mixed with the tiny water droplets also left behind in the flask. Before I started the next trial, it could have interfered with that titration and provide inaccuracy. Another error to mention is getting the exact endpoint during the titration. The indicator could have ranged from different shades of red (starting with orange) but I assumed that the moment it turned a standard red colour, it was finished. In addition, I could mention that I may not have properly swirled the solutions before beginning the titration process to make sure nothing (residue) settles at the bottom.This could have impacted the inaccurate colour change of the indicator in the neutralization and hence unknown standard colour. I also kept on adding drops when the solution was already a red colour towards the end. However, this may have either darkened or lightened the colour too much in an effort to change the precision of the indicator colour at the equivalence point or end point. Finally, at some moments, I was in a hurry to finish titrating, and so I may have flushed out the acid in large amounts. I realize that near the neutralization point, the acid must(prenominal) be released in dr ops. However, for the third trial, I did sort of flush out a large amount of the acid and therefore could have bewildered the neutralization point which could cause errors in results.