For each buffer system, calcutate the amounts (volume of stock solution or mass of solid) necessary to prepare 100 mL of the 0.10 M buffer at their desired pH. Show complete solution. Açetic acid-acetate buffer (100 ml, 0.100 M, pH 4.00) Stock Solutions: 1.0 M CH;COOH, 1.0 M NaCH;COO Relevant equilibrium: CH;COOH (aq) + H,O (1) = CH;CO0 (aq) + H;O* (aq) pK, = 4.74 Volume of 1.0M CH,COOH (mL): Volume of 1.0M NaCH,COO (mL):

For each buffer system, calcutate the amounts (volume of stock solution or mass of solid) necessary to prepare 100 mL of the 0.10 M buffer at their desired pH. Show complete solution. Açetic acid-acetate buffer (100 ml, 0.100 M, pH 4.00) Stock Solutions: 1.0 M CH;COOH, 1.0 M NaCH;COO Relevant equilibrium: CH;COOH (aq) + H,O (1) = CH;CO0 (aq) + H;O* (aq) pK, = 4.74 Volume of 1.0M CH,COOH (mL): Volume of 1.0M NaCH,COO (mL):

Principles of Modern Chemistry

8th Edition

ISBN:9781305079113

Author:David W. Oxtoby, H. Pat Gillis, Laurie J. Butler

Publisher:David W. Oxtoby, H. Pat Gillis, Laurie J. Butler

Chapter15: Acid–base Equilibria

Section: Chapter Questions

Problem 57P

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When 40.00 mL of a weak monoprotic acid solution is titrated with 0.100-M NaOH, the equivalence point is reached when 35.00 mL base has been added. After 20.00 mL NaOH solution has been added, the titration mixture has a pH of 5.75. Calculate the ionization constant of the acid.
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 exactly one litre of a propanoic acid buffer solution, containing 0.600 M C3H5OOH and 0.252 M C3H5OO- . 1.1 Determine the pH of the buffer solution. - You may use “HA” to denote the formula of the acid. - You may make certain assumptions to simplify your calculations - Ka for hydrofluoric acid is 1.3 × 10−5 . 3.2 Determine by means of a full calculation the change in pH of the buffer solution that will result when 100. mL of a 1.00 × 10−2 M HCℓ solution is added to it. You must indicate all the relevant reaction equations in your working.
Consider exactly one litre of a hydrofluoric acid buffer solution, containing 0.800 M HF and 0.528 M F-1. Determine the pH of the buffer solution.- You may use “HA” to denote the formula of the acid.- You may make certain assumptions to simplify your calculations- Ka for hydrofluoric acid is 6.6 × 10−42. Determine by means of a full calculation the change in pH of the buffer solution that will result when 100. mL of a 1.00 × 10−2 M HCℓ solution is added to it. You must indicate all the relevant reaction equations in your working.
A 20.00 mL aliquot of lactic acid solution (HCH3H5O3) was titrated with 0.0980 M KOH(aq) using both an indicator and a pH meter. Ka (HCH3H5O3), is 1.38 x10-4. A total of 28.64 mL of 0.0980 M KOH(aq) was required to reach the equivalence point 1. Calculate the molarity of the lactic acid solution. 2. Calculate the pH of the lactic acid solution 3. Calculate the pH and [CH3H5O3-] at the half-equivalence point. 4. Calculate the pH at the equivalence point of the titration. 5. Suggest an appropriate indicator for titration. 6. Calculate the pH of the solution after 10.00 mL of 0.0980 M NaOH(aq) was added
What will be the pH of the buffer solution consisting of 94 mL butanoic acid (CH3CH2CH2COOH) 0.189 mol/L and 109 mL sodium butanoate (CH3CH2CH2COONa) 0.207 mol/L, if 10.9 mL KOH 0.5 mol/L is added?Give an answer to at least 3 decimal places.
a.) A student titrated 50.0mL of a 0.10M solution of a certain weak acid with NaOH(aq). The results are given in the graph attached. (i) What is the approximate pKa of the acid? (ii) What specific value from the graph is needed, in addition to the information in part (a) above, to calculate the molar concentration of the NaOH(aq) ? (iii) Identify a pH value between 2.5 and 7.5 at which the concentration of the weak acid being titrated is less than the concentration of its conjugate base.
a. A buffer solution contains 0.387 M hydrocyanic acid and 0.409 M potassium cyanide.If 0.0293 moles of perchloric acid are added to 250. mL of this buffer, what is the pH of the resulting solution ?(Assume that the volume change does not change upon adding perchloric acid)pH = ? b. A buffer solution contains 0.329 M KHSO3 and 0.294 M K2SO3.If 0.0527 moles of sodium hydroxide are added to 225 mL of this buffer, what is the pH of the resulting solution ?(Assume that the volume does not change upon adding sodium hydroxide)pH = ? c. A buffer solution contains 0.459 M ammonium chloride and 0.396 M ammonia.If 0.0191 moles of sodium hydroxide are added to 125 mL of this buffer, what is the pH of the resulting solution ?(Assume that the volume change does not change upon adding sodium hydroxide)pH = ?
The stockroom contains 1M NaAc (Sodium Acetate), 1M HAc (Acetic Acid), distilled water and strong acids and bases. You need to create a buffer solution that has a pH of 4.75 such that when 1ml of 10M HCI is added to 100ml of your buffer, the resulting pH is 3.75 (+/-0.1). What concentrations of HAc and NaAc do you need to create the buffer solution?
A buffer solution is prepared by dissolving 1.50 g each of benzoic acid, HC7H5O2, and sodium benzoate, NaC7H5O2, in 150.0 mL of solution. (MM of benzoic acid=122.22g/mol, sodium benzoate=144.11g/mol) Ka=6.3x10-5 What is the pH of this buffer solution? Which buffer component must be added, and in what quantity, to change the buffer pH to 4.00? What quantity of 2.0 M NaOH or 2.0 M HCl must be added to the original buffer to change the pH to 4.00?
A buffer solution is prepared by dissolving 1.000 g of sodium acetate (CH3COONa) into 100.00 mL of a 0.100 M solution of acetic acid. Then 3.00 mL of a 2.00 M solution of sodium hydroxide is added to the acetic acid/sodium acetate buffer solution. The Ka of acetic acid is 1.8 × 10−5. What is the pH of the solution after adding NaOH?
Benzoic acid, C6H5COOH, dissociates in water as shown in the equation below. A 40.0 mL sample of an aqueous solution of benzoic acid with a concentration of 0.50 M is titrated using standardized 0.25 M NaOH. C6H5COOH(s) -> C6H5COO–(aq) + H+(aq) Ka = 6.46 x 10^-5 Calculate the pH of the solution after the following amounts of NaOH have been added… A. 0 mL B. 10 mL C. 85 mL