The weathering of pyrite (FeS2) in coal mines and in metal sulfide ore deposits can be represented by the following reaction
2FeS2 + 7O2 + 2H2O <--> 2Fe2+ +4SO42- +4H+
Given the following enthalpies, should miners be prepared to fight fires or to wear very warm clothing?
Species Change in Hfo (kJ/mol) (remember that 1 calorie = 4.184 joules)
FeS2 -171.5
H2O -285.8
Fe2+ -89.1
SO4 2- -909.3
H+ 0