4. In standardizing H2SO4 as a titrant, a 0.4512-g of primary-standard-grade Na2CO3 required 36.44 mL of the H2SO4 solution to reach the endpoint in the reaction: Co2- + 2 H* → H20 + CO:(g) a. How many moles of Na;CO3 (106 g/mol) is present? b. From your answer in a, how many moles of CO32- is present? C. From your answer in b, how many moles of H- is needed to completely neutralize CO32-?

4. In standardizing H2SO4 as a titrant, a 0.4512-g of primary-standard-grade Na2CO3 required 36.44 mL of the H2SO4 solution to reach the endpoint in the reaction: Co2- + 2 H* → H20 + CO:(g) a. How many moles of Na;CO3 (106 g/mol) is present? b. From your answer in a, how many moles of CO32- is present? C. From your answer in b, how many moles of H- is needed to completely neutralize CO32-?

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

Chapter15: Acid-base Equilibria

Section: Chapter Questions

Problem 14Q: Consider the following pH curves for 100.0 mL of two different acids with the same initial...

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Fifty cm3 of 1.000 M nitrous acid is titrated with 0.850 M NaOH. What is the pH of the solution (a) before any NaOH is added? (b) at half-neutralization? (c) at the equivalence point? (d) when 0.10 mL less than the volume of NaOH to reach the equivalence point is added? (e) when 0.10 mL more than the volume of NaOH to reach the equivalence point is added? (f) Use your data to construct a plot similar to that shown in Figure 14.10 (pH versus volume NaOH added).
Malonic acid (HO2CCH2CO2H) is a diprotic acid. In the titration of malonic acid w ith NaOH, stoichiometric points occur at pH = 3.9 and 8.8. A 25.00-mL sample of malonic acid of unknown concentration is titrated with 0.0984 M NaOH, requiring 31.50 mL of the NaOH solution to reach the phenolphthalein end point. Calculate the concentration of the initial malonic acid solution. (Sec Exercise 113.)
Consider the following pH curves for 100.0 mL of two different acids with the same initial concentration each titrated by 0.10 M NaOH. a. Which plot represents a pH curve of a weak acid, and which plot is for a strong acid? How can you tell? Cite three differences between the plots that help you decide. b. In both cases the pH is relatively constant before the pH changes greatly. Does this mean that at some point in each titration each solution was a buffered solution? c. True or false? The equivalence point volume for each titration is the same. Explain your answer. d. True or false? The pH at the equivalence point for each titration is the same. Explain your answer.
Lactic acid (CH3CHOHCO2H) is found in sour milk, in sauerkraut, and in muscles after activity. (Ka for lactic acid = 1.4 104.) (a) If 2.75 g of NaCH3CHOHCO2, sodium lactate, is added to 5.00 102 mL of 0.100 M lactic acid, what is the pH of the resulting buffer solution? (b) Is the pH of the buffered solution lower or higher than the pH of the lactic acid solution?
A 0.4000 M solution of nitric acid is used to titrate 50.00 mL of 0.237 M barium hydroxide. (Assume that volumes are additive.) (a) Write a balanced net ionic equation for the reaction that takes place during titration. (b) What are the species present at the equivalence point? (c) What volume of nitric acid is required to reach the equivalence point? (d) What is the pH of the solution before any HNO3 is added? (e) What is the pH of the solution halfway to the equivalence point? (f) What is the pH of the solution at the equivalence point?
Potassium hydrogen phthalate, known as KHP (molar mass = 204.22 g/mol), can be obtained in high purity and is used to determine the concentration of solutions of strong bases by the reaction HP(aq)+OH(aq)H2O(l)+P2(aq) If a typical titration experiment begins with approximately 0.5 g KHP and has a final volume of about 100 mL, what is an appropriate indicator to use? The pKa for HP is 5.51.
A 0.2481 M solution of KOH is used to titrate 30.00 mL of 0.269 M hydrobromic acid. Assume that volumes are additive. (a) Write a balanced net ionic equation for the reaction that takes place during the titration. (b) What are the species present at the equivalence point? (c) What volume of KOH is required to reach the equivalence point? (d) What is the pH of the solution 1. before any KOH is added? 2. halfway to the equivalence point? 3. at the equivalence point?
-4 A chemistry graduate student is given 250. mL of a 0.50M trimethylamine ((CH, N solution. Trimethylamine is a weak base with K 7.4 x 10. What mass of (CH,), NHCI should the student dissolve in the (CH, N solution to turn it into a buffer with pH =11.09? /3 You may assume that the volume of the solution doesn't change when the (CH, NHCI is dissolved in it. Be sure your answer has a unit symbol, and round it to 2 significant digits.
Consider the data obtained from titration of HCl with NaOH to a phenolphthalein end point: MHCl = 0.37M, VHCl = 25.10mL, VNaOH = 36.45 mL. a.How many millimoles of HCl are present at the end point, b. How many millimoles of NaOH are present at the end point, What is the molarity of NaOH
Jose titrated 40.00 mL of 0.25 M methylamine, CH3NH2, with 0.40 M HCI. CH3NH₂ Kb = 4.4 x 10-4 What volume of 0.40 M HCI is required to reach the equivalence point? Vol. HCI @ Equiv Pt Enter
Given: The pH of the buffer is 4.88 made by combining 0.500 L of 0.380 M HC3H5O2 (Ka=1.30X10-5) and 0.500 L of 0.380 M NaC3H5O2. 0.040 moles of HNO3 was added to the buffer. a. total moles of NaC3H5O2 in the solution? b. total moles of HC3H5O2 in the solution?
5. A 50.00 mL 0.1000 M HNO2 (Ka = 7.2 x 10-+) is being titrated with 0.1000 M NaOH. Calculate the pH of the solution before any amount of titrant is added. (Hint: Construct an ICE table) а. b. Calculate the volume of NAQH required to reach the equivalence point. Calculate the pH after the addition of 25.00 mL of NaOH. с. d. Calculate the pH at equivalence point. (Hint: Determine first the concentration of the conjugate base that was produced. You will construct an ICE table for the conjugate base.) e. Calculate the pH after adding 75.00 mL of NAQH. f. Using your answers from ato f, roughly generate a titration curve.