What would be your best choice to prepare a 100 mL of pH 5.5 buffer strength 0.50 M? (pKa of acetic acid = 4.756; for NaHCO3: pK1=6.351 and pK2=10.329) a. 0.025 moles of acetic acid and 0.025 moles of sodium acetic b. 0.25 moles of acetic acid and 0.25 moles of sodium acetic c. 0.015 moles of acetic acid and 0.035 moles of sodium acetic d. a. 0.25 moles of Na2CO3 and 0.25 moles of NaHCO3.

What would be your best choice to prepare a 100 mL of pH 5.5 buffer strength 0.50 M? (pKa of acetic acid = 4.756; for NaHCO3: pK1=6.351 and pK2=10.329) a. 0.025 moles of acetic acid and 0.025 moles of sodium acetic b. 0.25 moles of acetic acid and 0.25 moles of sodium acetic c. 0.015 moles of acetic acid and 0.035 moles of sodium acetic d. a. 0.25 moles of Na2CO3 and 0.25 moles of NaHCO3.

Chemical Principles in the Laboratory

11th Edition

ISBN:9781305264434

Author:Emil Slowinski, Wayne C. Wolsey, Robert Rossi

Publisher:Emil Slowinski, Wayne C. Wolsey, Robert Rossi

Chapter24: The Standardization Of A Basic Solution And The Determination Of The Molar Mass Of An Acid

Section: Chapter Questions

Problem 3ASA: A 0.3012g sample of an unknown monoprotic acid requires 24.13mL of 0.0944MNaOH for neutralization to...

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A 0.3012g sample of an unknown monoprotic acid requires 24.13mL of 0.0944MNaOH for neutralization to a phenolphthalein end point. There are 0.32mL of 0.0997MHCl used for back titration. a. How many moles of OH are used? How many moles of H+ from HCl? _______moles OH ________moles H+ b. How many moles of H+ are there in the solid acid? Use Eq.5. ____________ moles H+ in solid c. What is the molar mass of the unknown acid? Use Eq.4. ____________ g/mol
A 1.0-LL buffer solution contains 0.100 molHC2H3O2molHC2H3O2 and 0.100 molNaC2H3O2molNaC2H3O2. The value of KaKa for HC2H3O2HC2H3O2 is 1.8×10−51.8×10−5. Calculate the pHpH of the solution upon addition of 21.4 mLmL of 1.00 MHClMHCl to the original buffer. Express your answer using two decimal places.
If 21.6 mL of 0.107 M acid with a pKa of 5.16 is titrated with 0.105 M NaOH solution, what is the pH of the titration mixture at halfway to the equivalence point?
A biochemist needs 750 mL of an acetic acid–sodiumacetate buffer with pH 4.50. Solid sodium acetate(CH3COONa) and glacial acetic acid (CH3COOH) areavailable. Glacial acetic acid is 99% CH3COOH by massand has a density of 1.05 g/mL. If the buffer is to be 0.15 Min CH3COOH, how many grams of CH3COONa and howmany milliliters of glacial acetic acid must be used?
A 1.0-LL buffer solution initially contains 0.30 molmol of NH3NH3 (Kb=1.76×10−5)(Kb=1.76×10−5) and 0.30 molmol of NH4ClNH4Cl. What mass of the correct reagent should you add? Express your answer using two significant figures.
How will you prepare 500 ml of 0.750 M citrate buffer with pH of 4.25 from solid citric acid (C6H8O7) and solid sodium citrate (Na3C6H5O7).The Ka of citric acid is 7.40 x 10-4
What mass (in grams) of sodium acetate (MM=0.82 g/mol) is needed to prepare 500 ml of 75 mM acetate buffer with ph of 4.87? pka of acetic acid is 4.74. report your answer up to two decimal places
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For Ca2+ and Mg2+ determinations in a tap water sample, two 50 mL aliquots were pipetted and placed in different Erlenmeyer flasks. The first of them had the pH adjusted to 12 (Ca2+ titration) and the second to 10 (Ca2+ +Mg2+ titration). The volumes of EDTA (5.07*10-3 mol/L) used in the first and second titrations were 2.40 and 4.80 mL, respectively. Calculate: a) The concentration of Ca2+ in mg/L in the water sampleb) The concentration of Mg2+ in mg/L in the water sample
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The following text may be found at the ThermoFisher website: "PBS (phosphate buffered saline) is a pH-adjusted blend of ultrapure-grade phosphate buffers and saline solutions which, when diluted to a 1X working concentration, contains 137 mM NaCl, 2.7 mM KCl, 8 mM Na2HPO4, and 2 mM KH2PO4. Each 10X PBS solution is ready to use upon dilution to the desired concentration." This means that the product that you purchase has a concentration 10 times the concentration at which it is used. 1. Look up the pKa values for phosphoric acid and list them as a part of your response. 2. Based on the description of the contents of the PBS buffer, calculate the pH of the 1X solution. 3. Assume that you wish to use a pH = 7.00 buffer. If your answer to 2 was more acidic than pH 7.00, calculate how much 1.00 M NaOH you would need to add to get to pH = 7.00. If your answer to 2 was more basic than pH 7.00, calculate how much 1.00 M HCl you would need to add to get to pH = 7.00.
A solution contains NaHCO3, Na2CO3, and NaOH, either alone or in permissible combination. Titration of a 40.0-mL portion to a phenolphthalein end point requires 24.1 mL of 0.100 M HCl. A second 40.0-mL aliquot requires 48.4 mL of the HCl when titrated to a bromocresol green end point. Deduce the composition and calculate the molar solute conc. of the original solution