A biochemistry student wants to make an acidic buffer with pH of 4.20. They will start with 250 mL of a 0.5 M acetic acid (HC2H3O2) solution. Acetic acid has a pKa of 4.75. There are two ways to make this buffer. 1.1 The student is given 250 mL of a 0.5 M acetic acid (HC2H3O2) solution. What mass (in g) of sodium acetate (NaC,H¿O2: 82.03 g/mol) should they add to make this a solution with pH of 4.20? Round your answer to 3 significant digits. Assume that dissolving the solid will not change the volume of the solution. g of NaC,H;O2 1.2 The lab is currently out of sodium acetate. A friend suggests using sodium hydroxide. How does adding sodium hydroxide to an acetic acid solution make a buffer solution? Explain using a chemical equation. No calculation needed.

A biochemistry student wants to make an acidic buffer with pH of 4.20. They will start with 250 mL of a 0.5 M acetic acid (HC2H3O2) solution. Acetic acid has a pKa of 4.75. There are two ways to make this buffer. 1.1 The student is given 250 mL of a 0.5 M acetic acid (HC2H3O2) solution. What mass (in g) of sodium acetate (NaC,H¿O2: 82.03 g/mol) should they add to make this a solution with pH of 4.20? Round your answer to 3 significant digits. Assume that dissolving the solid will not change the volume of the solution. g of NaC,H;O2 1.2 The lab is currently out of sodium acetate. A friend suggests using sodium hydroxide. How does adding sodium hydroxide to an acetic acid solution make a buffer solution? Explain using a chemical equation. No calculation needed.

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...

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For humans to maintain the pH of their blood close to 7.4, the body uses three buffer systems: carbonate, phosphate and proteins. If the pH of the blood goes below 6.8 or above 7.8, death may result. Imagine you want to make a phosphate buffer in the lab that resembles the bloods phosphate buffer. You start by mixing 1.0 M NaH2PO4 and 0.50 M Na2HPO4. H2PO4- + H2O ⇌ HPO42- + H+ pKa= 7.21 From the reaction above indicate the weak acid and the conjugate base involved in making this buffer. Calculate the pH of the phosphate buffer solution. Provide your answer with 2 decimal places. If the pH calculated in b. was the blood pH of an actual patient, would you say this patient’s blood pH is in the normal range or are they suffering from alkalosis or acidosis?
Be sure to answer all parts.What is the [H3O+] and the pH of a benzoic acid-benzoate buffer that consists of 0.16 M C6H5COOH and 0.46 M C6H5COONa? (Ka of benzoic acid = 6.3 × 10−5) Be sure to report your answer to the correct number of significant figures.[H3O+] = _____pH = ______
where did the 3.18 come from?
What is the [H3O+] and the pH of a benzoic acid-benzoate buffer that consists of 0.13 M C6H5COOH and 0.30 M C6H5COONa? (Ka of benzoic acid = 6.3 × 10−5) Be sure to report your answer to the correct number of significant figures. [H3O+] = ___× 10___MpH =____
For humans to maintain the pH of their blood close to 7.4, the body uses three buffer systems: carbonate, phosphate and proteins. If the pH of the blood goes below 6.8 or above 7.8, death may result. Imagine you want to make a phosphate buffer in the lab that resembles the bloods phosphate buffer. You start by mixing 0.95 M NaH2PO4 and 0.68 M Na2HPO4. H2PO4- + H2O ⇌ HPO42- + H+ pKa= 7.21 (5 marks total) a. From the reaction above indicate the weak acid and the conjugate base involved in making this buffer. (2 marks) b. Calculate the pH of the phosphate buffer solution. Provide your answer with 2 decimal places (2 marks) c. If the pH calculated in b. was the blood pH of an actual patient, would you say this patient’s blood pH is in the normal range or are they suffering from alkalosis or acidosis? (1 mark)
Part A When a solution contains a weak acid and its conjugate base or a weak base and its conjugate acid, it will be a buffer solution. Buffers resist change in pH following the addition of acid or base. A buffer solution prepared from a weak acid (HA) and its conjugate base (A) is represented as What is the pH of a buffer prepared by adding 0.708 mol of the weak acid HA to 0.507 mol of NaA in 2.00 L of solution? The dissociation constant K of HA is 5.66 x 10-7. Express the pH numerically to three decimal places. HA(aq) = H+ (aq) + A-(aq) • View Available Hint(s) The buffer will follow Le Châtelier's principle. If acid is added, the reaction shifts to consume the added H+, forming more HA. When base the base will react with Ht, reducing its concentration. The reaction then shifts to replace H+ through the dissociation of HA into H+ and A. In both instances, H+] tends to remain constant. added, V AZO The pH of a buffer is calculated by using the Henderson-Hasselbalch pH = equation: pH =…
7. A solution was made by mixing 50.0 mL of 0.750 M HCN with 25.0 mL of water. What is the pH of this solution? The pka of HCN = 9.31. 8. One of the compounds featured on the TV series "Breaking Bad" was hydrofluoric acid (HF), pKa = 3.14. a) A solution of HF has a pH = 1.77. What was the initial [HF] for this solution in mol L-1? b) What is the equilibrium concentration of F in this solution in mol L-1? c) What is the percent ionization of HF in this solution?
answer pls
A buffer contains 0.175 moles C2H5NH3NO3 and 0.225 moles C2H5NH2 in 800.0 mL water. Kp (C2H5NH2) = 4.3 x 104 Express value to three decimal places. Determine the number of moles of base that can be added before the buffer capacity is exceeded. moles base F TOOLS x10
A scientist wants to prepare 500 ml of 500 mM formate buffer pH 3.00. The pKa for formic acid, нсоон, is 3.75. a. Identify the water components. b. Give the dissociation equation involved. c. Give the buffering action when the buffer system is added with (a) small amount of strong acids and (b) small amounts of strong base. d. What mass (in grams) of sodium formate (molar mass = 68 g/mol) is needed to separate the said buffer? Report the answer in 2 decimal places. (Show complete solution) e. What volume (in milliliters) of formic acid (molar mass = 46 g/mol; density = 1.22 g/mL) is needed to prepare the said buffer? Report the answer in 2 decimals places. (Show complete solution)
2
A student prepared 100.0 mL of a buffer in the lab that contains 0.300 M of a weak acid, HA, and 0.200 M of its conjugate base, NaA. The student then added 1.0x10 moles of NaOH to the buffer. a) Write down your student name and number b) Write down how the student calculated the final moles of A and HA after adding the NaOH: moles A finl =2.0x102 mole - 1.0x10-3mole moles HA na = 3.0x102mole +1.0x10-3mole c) There is an error in their formula. Identify the error d) Calculate the correct final moles of A and HA