Part 1: Standardising NaOH using KHP – Rough Titration Table 1: Rough Titration Data Volume of KHP: 25.00mL Molarity of KHP: 0.498 = 0.50 Indicator used: Phenolphthalein Initial Reading (mL) 2.00 mL Final Reading (mL) 15.30 mL Volume of NaOH added (mL) 13.30 mL This rough titration gives a general idea of how much NaOH is needed to reach the endpoint of the titration. While the endpoint in the rough titration is likely red in colour it should actually be pale pink. The more base added the deeper the colour of the indicator. A dark colour means that you have overshot the endpoint and added too much NaOH. Part 1: Standardising NaOH using KHP Table 2: Standardisation of NaOH Data Volume of KHP: 25.00mL Molarity of KHP: 0.498 = 0.50 Indicator used: Phenolphthalein Titration Number* | Initial Reading (mL) | Final Reading (mL) | Volume of NaOH 1 | 2.00 mL | 15.26 mL | 13.26 mL 2 | 2.00 mL | 14.25 mL | 12.25 mL 3 | 2.00 mL | 13.75 mL | 11.75 mL Average Titre | 12.75 mL
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KHP (KHC8H4O4) + NaOH -> KNaC8H4O4 + H2O Stoichiometry: 1 mol KHP reacts with 1 mol NaOH, so at the endpoint n(NaOH) = n(KHP). Show more…
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Standardization by Titration Molar Concentration of NaOH Data, Calculations, Results & Report Sheets [Report Answers to the Correct Number of Significant Figures & Don't Forget to Include Units] Data: Table 1 Trial 1 Trial 2 1. Mass of KHP 3.009 g 3.246 g Data: Table 2 Trial 1 Trial 2 2. Final Buret Reading 43.33 mL 47.13 mL 3. Initial Buret Reading .50 mL 1.20 mL 4. Volume of NaOH Used (in mL) 5. Volume of NaOH Used (in L) [convert from mL to L] Results: Table 3 Trial 1 Trial 2 6. # Moles of KHP Titrated 7. # Moles of NaOH Required to React with KHP 8. Concentration of NaOH Solution (in Molarity) 9. Average Concentration of NaOH Solution (in Molarity) Q1) Show how you calculated the number of moles of KHP (line 6.) titrated for both trials #1 and #2. Q2) Show how you calculated the number of moles of NaOH required to completely react with the moles of KHP (line 7.) for both trials #1 and #2. Q3) Show how you calculated the concentration of the NaOH solution (line 8.) for both trials #1 and #2. Q4) In this experiment, why do you add phenolphthalein to the solution before the titration begins?
Shaiju T.
1. Calculate the volume in milliliters (mL) of a 6.00 M NaOH solution needed to make 5.00 x 10^2 mL of a 0.100 M NaOH solution. (Recall that M = molar = mol/L, and show all your work). 2. An approximately 0.1 M NaOH solution was standardized with KHP by titration to a phenolphthalein endpoint. From the following data, calculate the average molarity of the NaOH. The molar mass of KHP is 204.22 g/mol. Trial 1 Trial 2 Mass of weighing paper + KHP 2.5489 g 2.4683 g Mass of weighing paper 2.0467 g 2.0462 g Mass of KHP Moles of KHP Final buret reading 25.62 mL 23.74 mL Initial buret reading 0.25 mL 2.45 mL Volume of NaOH (mL) Molarity of NaOH (moles per liter) Average molarity 3. Calculate the average molarity, standard deviation (SD), and percent (%) variation of the three titration molarities given below. Recall: % variation = (SD/mean)*(100%). Molarity of HCl: 0.2056 M 0.2048 M 0.2053 M Average Molarity: ± (SD) [UNITS!] Percent (%) variation: Is the percent variation less than 1%?
Dj T.
Part 1. Standard NaOH solution 1. The masses of three KHP samples: 0.7259 g 0.7209 g 0.7500 g 2. Titration with NaOH solution (results): 34.45 mL 34.19 mL 35.55 mL 3. The molarity of NaOH: 0.103193 moles / L 0.103247 moles / L 0.103319 moles / L Hint: Calculate the number of moles of KHP in each sample (#). The number of moles of NaOH used for titration is the same. The molarity of NaOH is: # / volume of NaOH solution used. 4. The average molarity of NaOH 0.103253 moles/L Part 2. Unknown sample of a monoprotic acid. Unknown Weight: 4.9738 grams in 250 mL's 5. Titration results Equivalence point: Titration 1 (approximate): 30.72 mL NaOH solution Titration 2: 31.20 mL NaOH solution Titration 3: 31.32 mL NaOH solution 6. Calculate the number of moles of a monoprotic acid present in the sample: moles titration 2 moles titration 3 7. Calculate the molecular weight of unknown acid: Hint: The molecular weight is equal to the mass of an unknown acid divided by the number of moles. g/mole titration 2 g/mole titration 3 8. Using your titration curve determine the pKa of an acid: pKa = Attach all your calculations on separate piece of paper.
Sri K.
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