Suppose you have an aqueous solution prepared by dissolving 0.051 mol of NaH2PO4 in 1 L of water (pK, (H2P04¯) = 7.21). This solution is not a buffer, but suppose you want to make it into one. How many moles of solid NaH2 PO4 must you add to this aqueous solution to make it into: a. A buffer of pH 7.21 n = mol b. A buffer of pH 6.21 mol c. A buffer of pH 8.21 n = mol

Suppose you have an aqueous solution prepared by dissolving 0.051 mol of NaH2PO4 in 1 L of water (pK, (H2P04¯) = 7.21). This solution is not a buffer, but suppose you want to make it into one. How many moles of solid NaH2 PO4 must you add to this aqueous solution to make it into: a. A buffer of pH 7.21 n = mol b. A buffer of pH 6.21 mol c. A buffer of pH 8.21 n = mol

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

9. Calculate the pH of a solution prepared by mixing 50.0 mL of 0.100 M imidazole (a weak base) with 4.20 mL of 0.500 M HCl. pKb of imidazole is 7.05. CO.T Imidazole-H (Im H¹) A. 5.88 B. 6.81 C. 7.09 D. 9.16 H* + N Imidazole (Im) SHq tam? IndW MM LOS diw bots 50.8 x 101 8 SI.LL. 29.1.XI
25). One of your classmates, Chem 109 student said, “I can make a perchlorate buffer using equal amount of 0.1 M HCIO4 and 0.1 M NaCIO4." Will the solution prepared properly by this student functions as a buffer? Another word, can this solution be a buffer? а. yes d. need only ClIO, to make the buffer. c. need only HCIO, to make a perchlorate buffer. e. none of the above b. no
A 50.00-mL solution of 0.0400 M nitrous acid ( K a = 4.5 × 10 –4) is titrated with 20.00 mL of a 0.100 M solution of NaOH as the titrant. What is the pH of at the equivalence point? ( K w = 1.00 × 10 –14) a. 7.59 b. 11.45 c. 7.14 d. 7.90 e. 7.80 f. None of the above
Which of the following, when mixed, would NOT result in a buffer solution? а. 10 mL of 0.1M HCI and 20 mL of 0.1 M NH3 O b. 10 mL of 0.1 M HCI and 20 mL of 0.1 M NaC2H3O2 C. 10 mL of 0.1 M NaOH and 20 mL of 0.1 M potassium cyanide, KCN d. 10 mL of 0.1 M NaOH and 20 mL 0.1 M HF e. 10 mL of 0.1 M acetic acid, HC2H3O2, and 10 mL of 0.1 M sodium acetate, NaC2H3O2
Hh.129.
Ka(HOAC) = 1.8 x 10-5. A 1-L buffer solution is prepared by mixing 0.35 mol HOAC and 0.45 mol NaOAc. Which of the following processes will increase the pH of the above buffer solution? O a. add more water b.add more HOA c. add some HCI into the above buffer SO d. add some NH3 into the above buffer e. None of the above
22. Which of the following mixture could be considered as a buffer? Hint: Try to react each mixture (if possible) and look for a pair that could be components for the buffer c. HC1 + CF d. CH3COO+ OH- a. NH4C1 + NAOH b. NH3 + NaOH 23. What is the pH of a buffer solution containing 0.25 M acetic acid and 0.030 M sodium acetate? The acid dissociation constant for acetic acid is equal to 1.8 x 10 Hint no dilution occurred a. 3.82 b. 5.67 C. 10.18 d. 8.34
5. A common buffer solution can be prepared by using ammonia and ammonium salts. The base equilibrium constant is 1.815×10-5. A student is preparing a pH buffer solution with 2.561 M NH3 solution and (NH4)2SO4 solid. Please answer the following questions. A. B. What is the best pH buffer range of the buffer solution that can be prepared by NH3 solution and (NH4)2SO4 solid? Please put down "1" if the answer is pH = 4.741 ± 1, please put down "2" if the answer is pH = 4.741 ± 10, please put down "3" if the answer is pH = 9.26 ± 1, please put down "4" if the answer is pH = 9.26 ± 10. Your answer follows. Assume that the addition of the solid will NOT change the volume, how many grams of is needed to prepare a pH = 8.66 buffer solution? The volume of the buffer solution is 250.0 mL. grams
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?
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)
While buffer preparation, the buffer solution is 0.1M with a pH of 6.70. What is the correct system to prepare the target buffer? Afterwards, what are the concentrations of the acidic and basic species in the buffer (in M)? a. H3PO4 and H₂PO4- b. H₂PO4 and HPO4²- c. HPO4²- and PO4³-
8. Which of the following conjugate acid-base pair would you choose to prepare a buffer solution that has a pH of 4.20? A. HSO4-/SO42- (Ka = 1.2x10-²) B. C6H5COOH and C6H5COO-(Ka = 6.3 x 10-5) C. HCIO and CIO- (Ka = 3.5 x 10-8) D. HPO4-2 and P04-3 (Ka = 3.6 x 10-¹³) E. None of the choices