Problem 118
A sample of hard water was found to have 278 ppm \(\mathrm{Ca}^{2+}\) ion. Into \(1.00 \mathrm{~L}\) of this water, \(1.00 \mathrm{~g}\) of \(\mathrm{Na}_{2} \mathrm{CO}_{3}\) was dissolved. What is the new concentration of \(\mathrm{Ca}^{2+}\) in parts per million? (Assume that the addition of \(\mathrm{Na}_{2} \mathrm{CO}_{3}\) does not change the volume, and assume that the density of the aqueous solutions involved are all \(1.00 \mathrm{~g} \mathrm{~mL}^{-1}\).)
Problem 132
The \(\mathrm{pH}\) of a saturated solution of \(\mathrm{Mg}(\mathrm{OH})_{2}\) is 9.8 . Determine the \(K_{\mathrm{sp}}\) for \(\mathrm{Mg}(\mathrm{OH})_{2}\)
Problem 136
If aqueous ammonia is added gradually to a solution of copper sulfate, a pale blue precipitate forms that then dissolves to give a deep blue solution. Describe the chemical reactions that take place during these changes.
Problem 140
Suppose two silver wires, one coated with silver chloride and the other coated with silver bromide, are placed in a beaker containing pure water. Over time, what if anything will happen to the compositions of the coatings on the two wires? Justify your answer.
