Homework #7

Last updated
Save as PDF

Page ID: 42487

\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\)

Due on Mar 4 (Friday)

Q1

Calculate the pH at the following points in a titration of 40.0 mL of 0.100 M benzoic acid (\(K_a= 6.3\times10^{−5}\)) with 0.200 M KOH.

10.0 mL of KOH solution added
15.0 mL of KOH solution added
At the equivalence point. Verify any assumption you made.
21.0 mL of KOH solution added

Q2

Ethylamine, C₂H₅NH₂, is a weak base. 250.0 mL of a 0.160 M C₂H₅NH₂ solution is titrated with 0.500 M HCl (aq). Find the \(K_b\) value in a lecture slide. Calculate the pH at the following points.

30. mL of HCl solution added.
At the halfway point.
At the equivalence point. Verify any assumption you made.
90. mL of HCl solution added.

Q3

Assuming that no equilibria other than dissolution are involved, calculate the molar solubility of PbI₂(\(K_{sp}=7.1\times10^{-9}\)).

Q4

How many moles of Ag₂CO₃ (\(K_{\rm sp}=8.5\times 10^{-12}\)) will dissolve in 500. mL of 0.010 M (NH₄)₂CO₃ solution?

Q5

Calculate the molar solubility of Cr(OH)₃ (\(K_{\rm sp}=6.3\times 10^{-31}\)) in a buffer solution of a pH of 10.10.