Although we tend to make less use of mercury these days because of the environmental problems created by its i

Although we tend to make less use of mercury these days because of the environmental problems created by its improper disposal, mercury is still an important metal because of its unusual property of existing as a liquid at room temperature. One process by which mercury is produced industrially is through the heating of its common ore cinnabar (mercuric sulfide, HgS) with lime (calcium oxide, CaO).

4 HgS(s) + 4 CaO(s) 4 Hg(l) + 3 CaS(s) + CaSO4(s)

What mass of mercury would be produced by complete reaction of 10.5 kg of HgS?Although we tend to make less use of mercury these days because of the environmental problems created by its i10.5 Kg HgS *1000g/kg = grams HgS reacted. Divide this number by the molecular weight of HgS to find the number of moles of HgS reacted. This is, by the balanced reaction, the same as the number of moles of Hg(l) produced. Multiply the number of moles by the molecular weight of Hg and you have the mass of mercury produced in the reaction.