Describe the preparation of 2 L of 85 mM phosphate buffer, pH 6.5, using 120 mM NaH₂PO4-6H₂O and 120 mM Na₂HPO4-6H₂O. The pka of the weak acid component is 7.21. Show calculations- Molar masses of some elements. ELEMENT MOLAR MASS. g/mol Na 22.99 H 1.008 P 30.97 O 16.00 CI 35.45

Describe the preparation of 2 L of 85 mM phosphate buffer, pH 6.5, using 120 mM NaH₂PO4-6H₂O and 120 mM Na₂HPO4-6H₂O. The pka of the weak acid component is 7.21. Show calculations- Molar masses of some elements. ELEMENT MOLAR MASS. g/mol Na 22.99 H 1.008 P 30.97 O 16.00 CI 35.45

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter1: Chemical Foundations

Section: Chapter Questions

Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...

See similar textbooks

Similar questions

A manufacturer has stated that the fluoride level of a mouthwash is 0.04% NaF. Assuming that you will use a 100 mL flask, calculate the volume of mouthwash that you will need to place into this volumetric so that the final solution is diluted into the 2 ppm F− (not NaF) range of the instrument
ou are tasked with determining a way to identify the following ions in solution: Na+, Ni2+, Ag+, and Pb2+. What techniques would you use to selectively precipitate out the ions and how would you separate the precipitates from the supernatant layers? Your arsenal of compounds to use for the separation is KCl, KCH3COO, and KOH. Clearly define each step.
A pharmacist needs to prepare an oral solution for valproic acid at a dose of 144 mg. If you prepare a 10 mL valproic acid solution using a buffer solution at pH 3.8, what is the solution pH? Valproic acid has a pKa value of 4.8. MW = 144 What is the percentage of valproic acid that exists in the deprotonated (ionized) form?
12
An analytical chemist is titrating 127.2 mL of a 0.9000M solution of nitrous acid (HNO₂) with a 1.200M solution of KOH. The pK of nitrous acid is 3.35. a Calculate the pH of the acid solution after the chemist has added 105.0 mL of the KOH solution to it. Note for advanced students: you may assume the final volume equals the initial volume of the solution plus the volume of KOH solution added. Round your answer to 2 decimal places. pH = X S
In the titration of 25.00 mL of a water sample, it took 19.040 mL of 4.965x 10−3 M EDTA solution to reach the endpoint. The total hardness is always listed in parts-per-million (ppm) of CaCO3 (or mg CaCO3 / Kg H2O). Since the density of water is 1.0 g/mL, one ppm would be the same as the number of mg of CaCO3 per liter of water. Determine the number of moles of CaCO3 present in the titrated sample of water, assuming that all the Ca2+ combines with CO32−. (enter your answer with 3 significant figures)
A student performed three H2SO4 titrations in Part 2 using their 0.1048 M NaOH solution which they previously standardized in Part 1. They reported the following measurements: Determination #1 Determination #2 Determination #3 Final NaOH Burette Reading 37.65 mL 28.35 mL 26.23 mL Initial NaOH Burette Reading 12.80 mL 4.05 mL 1.73 mL For every 1 mole of H2SO4, how many moles of NaOH are needed to reach equivalence in the titration? Report the integer number only (no units).
Calculate Qsp for calcium fluoride (Ksp = 3.9 ×10^–11) when 225.0 mL of a 6.15×10^-3 M solution of Ca(NO3)2 is added to 290.0 mL of a 7.35×10^-3 M solution of KF.
You used the back-titration method to experimentally determine the amount of CaCO3 in an Ultra Strength Tums antacid tablet. You calculated that you used 21.5 mmol HCl to complete the titration of a 2.139 g Tums tablet. What is the mass (in mg) of the active ingredient in the Tums tablet? (CaCO3 = 100.1 g/mol)
Molarity of titrant (NaOH): 0.4550 M HC2H3O2 (aq) + NaOH (aq) → NaC2H3O2 (aq) + H2O (l) Trial # First Second Third Fourth Initial buret reading 0.15 mL 2.43 mL 1.32 mL 0.58 mL Final buret reading 18.62 mL 20.87 mL 20.03 mL 19.14 mL Volume of titrant used 18.47 mL 18.44 mL 18.71 mL 18.56 mL 4) Calculate the molarity of the acetic acid in the vinegar solution (Show your work). use FW for moles-->grams acetic acid. Molarity acetic acid = _____________ M 5) Calculate the weight % of acetic acid in the vinegar. How does this compare with the % listed on the label (5.00%)? (For this calculation assume that density of vinegar is 1.03 g/mL and of course, show your work). Weight % = ___________ 6) If you didn’t get the same weight % of acetic acid as listed on the vinegar label (5.00 %), what are two things (be specific) that could’ve happened during the experiment that could explain the variation from the expected weight %? To do…
A 50.0 mL solution of Ca(OH)₂ with an unknown concentration was titrated with 0.340 M HNO₃. To reach the endpoint, a total of 26.0 mL of HNO₃ was required. Given that 0.00442 mol of Ca(OH)₂ were present, what was the concentration of the initial Ca(OH)₂ solution?