Wollaston equivalents

William Hyde Wollaston presented an early compilation of "equivalent weights" or combining masses (closely related to molar masses) in 1813. He drew upon some experimental data of his own and a large body of chemical analyses published by other scientists. This exercise deals with some of that analytical data on composition of simple inorganic compounds. In what follows, Wollaston was talking about parts by mass, so read "grams" where he says "parts".

a) He reported that litharge, a lead oxide, contains 7.15 parts oxygen to 92.85 parts lead. Using a modern periodic table, find the molar ratio of oxygen to lead in this compound and determine its empirical formula.
b) He reported that galena, a lead sulfide, contains 13.36 parts sulfur to 86.64 parts lead. Using a modern periodic table, find the molar ratio of sulfur to lead in this compound and determine its empirical formula.
c) He reported that the "corrosive sublimate of mercury," a compound of mercury and chlorine, contains 2x67 parts chlorine to 380 parts mercury. Using a modern periodic table, find the molar ratio of chlorine to mercury in this compound and determine its empirical formula.

Reference

William Hyde Wollaston, "A Synoptic Scale of Chemical Equivalents," Philosophical Transactions of the Royal Society 104, 1-22 (1814)

Back to the Classic Calculations home page

Back to the top of the Classic Chemistry site