Chapter 20 Laboratory: Quantitative Analysis 371RQEWEvI UESTIOnS
q 1 : How do the values for chloride and sulfate ion concentrations you determined experimentally compare with the standard
values given in the introduction? If the values differ significantly, propose at least one explanation. (Reasonable explanations may
differ depending on whether you’re using natural or synthetic seawater.)
q: 2 List at least five possible sources of experimental error.
q: 3 Other than sodium, the two cations that are present in the highest concentrations in seawater are magnesium (1.17%) and
calcium (1.13%). Look up the solubility product constants for magnesium and calcium in combination with various anions and
use that information to choose a common reagent anion that could be used to selectively precipitate magnesium while leaving
calcium in solution. Choose another common reagent anion that could be used to selectively precipitate calcium ions while
leaving magnesium ions in solution.