A chemistry graduate student is given 500. mL of a 0.60M nitrous acid (HNO,) solution. Nitrous acid is a weak acid with K=4.5 x 10 -4 What mass of KNO, should the student dissolve in the HNO, solution to turn it into a buffer with pH = 3.88? You may assume that the volume of the solution doesn't change when the KNO, is dissolved in it. Be sure your answer has a unit symbol, and round it to 2 significant digits.

A chemistry graduate student is given 500. mL of a 0.60M nitrous acid (HNO,) solution. Nitrous acid is a weak acid with K=4.5 x 10 -4 What mass of KNO, should the student dissolve in the HNO, solution to turn it into a buffer with pH = 3.88? You may assume that the volume of the solution doesn't change when the KNO, is dissolved in it. Be sure your answer has a unit symbol, and round it to 2 significant digits.

Chemistry: The Molecular Science

5th Edition

ISBN:9781285199047

Author:John W. Moore, Conrad L. Stanitski

Publisher:John W. Moore, Conrad L. Stanitski

Chapter15: Additional Aqueous Equilibria

Section: Chapter Questions

Problem 111QRT: Consider the nanoscale-level representations for Question 111 of the titration of the aqueous strong...

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Consider the nanoscale-level representations for Question 110 of the titration of the aqueous weak acid HX with aqueous NaOH, the titrant. Water molecules and Na+ ions are omitted for clarity. Which diagram corresponds to the situation: After a very small volume of titrant has been added to the initial HX solution? When enough titrant has been added to take the solution just past the equivalence point? Halfway to the equivalence point? At the equivalence point? Nanoscale representations for Question 110.
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You place 1.234 g of solid Ca(OH)2 in 1.00 L of pure water at 25 C. The pH of the solution is found to be 12.68. Estimate the value of Ksp for Ca(OH)2.
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Consider the nanoscale-level representations for Question 111 of the titration of the aqueous strong acid HA with aqueous NaOH, the titrant. Water molecules and Na+ ions are omitted for clarity. Which diagram corresponds to the situation: (a) After a very small volume of titrant has been added to the initial HA solution? (b) Halfway to the equivalence point? (c) When enough titrant has been added to take the solution just past the equivalence point? (d) At the equivalence point? Nanoscale representations for Question 111.
Marble is almost pure CaCO3. Acid rain has a devastating effect on marble statuary left outdoors. Assume that the reaction which occurs is CoCO3(s)+ H+(aq)Ca2+(aq)+HCO3(aq) Neglecting all other competing equilibria and using Tables 15.1 and 13.2, calculate (a) K for the reaction. (b) the molar solubility of CaCO3 in pure water. (c) the molar solubility of CaCO3 in acid rainwater with a pH of 4.00.
The weak base ethanolamine. HOCH2CH2NH2, can be titrated with HCl. HOCH2CH2NH2(aq)+H3O+(aq)HOCH2CH2NH3+(aq)+H2O(l) Assume you have 25.0 mL of a 0.010 M solution of ethanolamine and titrate it with 0.0095 M HCl. (Kb for ethanolamine is 3.2 107.) (a) What is the pH of the ethanolamine solution before the titration begins? (b) What is the pH at the equivalence point? (c) What is the pH at the halfway point of the titration? (d) Which indicator in Figure 17.11 would be the best choice to detect the equivalence point? (e) Calculate the pH of the solution after adding 5.00, 10.0, 20.0, and 30.0 mL of the acid. (f) Combine the information in parts (a), (b), (c), and (e), and plot an approximate titration curve.
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