Answer to Question #239126 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

Calculate the heat evolved (in kJ) per gram of ZnS roasted

Answer 1

In this item, we are provided the heat released for each 2mols of ZnS is 879kJ

Amount of ZnS = 2mols of ZnS ×97.474g/mol = 194.9 g ZnS

Heat released = 879/194.9

= 4.5kJ/g