Let's check the phone application "buffers" for it's ability to calculate how to prepare a phosphate buffer. Suppose I want 1 liter of a 0.1 M phosphate buffer at a pH of 6.8. Phosphate has a pK2 of 7.2 MW of monosodium phosphate NaH2PO4 (aka monobasic) is 119.98 MW of disodium phosphate Na2HPO4 (aka dibasic) is 141.96 Let's first calculate the fraction of dibasic we need from the H-H equation. In other words solve for A-/total. Calculate to 3 sig figures

Let's check the phone application "buffers" for it's ability to calculate how to prepare a phosphate buffer. Suppose I want 1 liter of a 0.1 M phosphate buffer at a pH of 6.8. Phosphate has a pK2 of 7.2 MW of monosodium phosphate NaH2PO4 (aka monobasic) is 119.98 MW of disodium phosphate Na2HPO4 (aka dibasic) is 141.96 Let's first calculate the fraction of dibasic we need from the H-H equation. In other words solve for A-/total. Calculate to 3 sig figures

Chemistry: Principles and Reactions

8th Edition

ISBN:9781305079373

Author:William L. Masterton, Cecile N. Hurley

Publisher:William L. Masterton, Cecile N. Hurley

Chapter14: Equilibria In Acid-base Solutions

Section: Chapter Questions

Problem 34QAP: A buffer is prepared using the butyric acid/butyrate (HC4H7O2/C4H7O2)acid-base pair. The ratio of...

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A buffer is prepared using the butyric acid/butyrate (HC4H7O2/C4H7O2)acid-base pair. The ratio of acid to base is 2.2 and Ka for butyric acid is1.54105. (a) What is the pH of this buffer? (b) Enough strong base is added to convert 15% of butyric acid to the butyrate ion. What is the pH of the resulting solution? (c) Strong acid is added to the buffer to increase its pH. What must the acid/base ratio be so that the pH increases by exactly one unit (e.g., from 2 to 3) from the answer in (a)?
Consider the following two acids: pKa1 = 2.98; pKa2 = 13.40 HO2CCH2CH2CH2CH2CO2H Adipic acid pKa1 = 4.41; pKa2 = 5.28 In two separate experiments the pH was measured during the titration of 5.00 mmol of each acid with 0.200 M NaOH. Each experiment showed only one stoichiometric point when the data were plotted. In one experiment the stoichiometric point was at 25.00 mL added NaOH, and in the other experiment the stoichiometric point was at 50.00 mL NaOH. Explain these results.
BUFFERS, HYDROLYSIS OF SALTS 1. A 0.0250 M Ca(X)2 has a pH of 8.049. Ca(X)2 is composed of a Ca2+ cation and an unknown anion X, which undergoes hydrolysis. A. Write the balanced dissociation reaction of Ca(X)2 into its ions. Write your answer on your solution sheet B. Write the balanced hydrolysis reaction of the unknown anion, X. Write your answer on your solution sheet C. Calculate the K₁ or Kb of X. D. Given the following Ką values of different weak acids, determine the identity of X. Weak acids Ka HIO 2.00 x 10-11 HCN 6.17 x 10-10 CH3COOH 1.80 x 10-5 HNO₂ 4.00 x 10-4 ts
2. Phoebe was tasked to ensure that an enzyme responsible for keeping her species from extinction remains biologically active. To do so, she needs to store it in a buffer solution with a pH of 10.00. Unfortunately, only three buffer systems are available in their laboratory: Buffer System Weak Acid Component K₂ Conjugate Base Salt PAH Benzoic acid, C6H5COOH 6.25 x 10-5 NaC6H5COO SAD Boric acid, H3BO3 5.81 x 107 NaH₂BO3 DOH Hydrogen cyanide, HCN 6.20 X 10-10 NaCN A. In what buffer system (PAH, SAD, or DOH) will Phoebe store the enzyme? In your solution sheet, show calculations and briefly explain to support your answer. B. Write the equilibrium reaction involved in the buffer system. Write your answer on your solution sheet C. Calculate the amount (in mL) of the 2.00 M stock solution (pH 10.00) of the same buffer system needed to prepare 250 mL of a 0.650 M buffer pH 10.00.
Calculate the % relative error in hydronium ion concentration by using concentrations instead of activities in calculating the pH of the following buffer solutions using the thermodynamic constants listed below. Acid Formula K₂ Acetic acid CH, COOH 1.75 x 10-5 Ammonium ion NH₂+ 5.70 x 10-10 Chloroacetic acid CICH, COOH 1.36 x 10-³ b 0.0340 M NH3 and 0.120 M NH, CI Relative error = C 0.0210 M CICH₂ COOH and 0.0570 M CICH₂ COONa (αCICH, COO = 0.35) Relative error =
Given the following buffer systems, the acetate buffer system would be the best choice to create a buffer of pH = 5.5. If True, show how much of each component is needed to prepare 2.5 L of the buffer system. CH3COOH (Ka = 1.77 x 10¯5) & CH3COOK HClO2 (Ka = 1.1 x 10¯2) & KClO2 NH3 (Ka = 5.65 x 10¯10) &NH4Cl HClO (Ka = 2.9 x 10¯8 )& KClO
You may want to reference (Page 834) Section 18.3 while completing this problem. Part A If 130.0 mL of 0.0020 M Na2SO4 (aq) is saturated with CaSO4, how many grams of CaSO4 would be present in the solution? [Hint. Does the usual simplifying assumption hold?] Express your answer using two significant figures. VE ΑΣΦ ? m = 0.43 Submit Previous Answers Request Answer X Incorrect; Try Again; 3 attempts remaining g
One strategy for dealing with the acidification of lakes is periodically to add powered limestone (CaCO3) to them, resulting in pH of 10.95. Calculate the Ca2+ concentration in the lake. CO2 in atmosphere 370 ppm KH,CO2 = 0.033 mol/(L∙atm) Ka1 = 10-6.3 Ka2 = 10-10.3 Ksp,CaCO3 = 4.57 x 10-9
The pK₂ value for HF is 3.14. Would a buffer prepared from HF and KF with a pH of 4.94 be considered to be an effective buffer? A buffer in which the mole ratio of KF to HF is 1.8 has a pH of 3.39. Would this buffer solution have a greater capacity for added acid (H3O+) or added base (OH¯)?
1) What is the reason 2) In order to determine the hardness of water, 100 mL sample is taken. After neutralizing the sample, pH 10 buffer solutions and Erichrom black-T indicator are added. This sample is titrated with 10.7 mL of the solution containing 3.7225 g EDTA in 1 L distilled water. Calculate the hardness of water in terms of considering the amount of CaCO3 present in the sample. (Mwt Ca:40 g/mole, O:16 g/mole, C:12 g/mole, EDTA: 372,25 g/mole)
A buffer was made with HC2H3O2 and its conjugate base. What is the pH of the buffer if at equilibrium there was [HC2H3O2] = 0.5000 M and [C2H302ª] = 0.7000 M and the Ka = 1.60 x 10-5 ? everything is based upon the acid dissolving in water: HC2H3O2 + H20 C2H3O21 + H30*1 [ Ka = [ solve for [H30*'] then put in the numbers Ka [ ( [H3O+1] : [ ] [H3O+'] = pH = - log d. HC6H6O61 f. SO3? a. H30+1 b. Он1 c. H2C6H606 е. HSO31 -2 g. H2SO3 h. HC2H3O2 i. C2H3O21 j. H2S k. HS-1 I. s2 m. HX п. X-1 О. 1 р. 2 q. 3 r. 0.5000 s. 5.5 X 10-5 t. 3.5 X 10-4 u. 8.00 x 10-5 v. 1.75 x 10-6 w. 1.11 x 10-8 х. 5.5 х 102 y. 0.7000 z. 1.60 x 10-5 аа. 1.143 х 10-5 bb. 0.4900 сс. 1.104 х 10-5 dd. 0.7100 ее. 1.26 х 10-5 ff. 4.901 gg. 7.93 hh. 4.942 ii. 4.957
The desired pH is 6.4 in creating a buffer system/buffer solution of about 50-60mL. Therefore, a student picks Silicic Acid Si(OH)4, as 1mL of 1M of the acid has a pH of 6.4, which also has a pKa of 9.82. What is the ratio HA/A- and ratio A-/HA-? The buffering capacity will be checked by the addition of 1mL of 1M HCl or 1mL of 1M NaOH and should not change by more than 0.25pH units.