Answer to Question #239125 in General Chemistry for KING

Question

 The first step in the industrial recovery of zinc from the zinc sulfide ore is roasting, that is, the conversion of ZnS to ZnO by heating:

2𝑍𝑛𝑆(𝑠) + 3𝑂2(𝑔) → 2𝑍𝑛𝑂(𝑠) + 2𝑆𝑂2(𝑔) ∆𝐻 = −879 𝑘𝐽 𝑚𝑜𝑙

Answer 1

From conditions, heat evolved is 879 kJ per 2 moles ZnS, molar mass of ZnS is 97.5 g/mole. Heat evolved per 1 g of ZnS is:

879/(2*97.5) = 4.508 kJ per gram