Question

An ore contains 2.0% by weight of the mineral argentive (Ag2S).How much of ore should be taken to produce 1.0g pure Ag?

Answer 1

Considering that you can get all the silver present in the ore:

In 1 mol Ag2S, i.e. in 247.8014 g Ag2S, we have 2 mol Ag, i.e. 215.7364 g Ag.

In other words, 1 g Ag is contained in about 1.14863 g Ag2S.

Further, the ore is just 1.34. So, the ore required for extracting 1 g Ag is about 85.72 g.