Question

The most common source of copper (cu) is the mineral chalcopyrite (cufes2). how many kilograms of chalcopyrite must be mined to obtain 370. g of pure cu?

Answer 1

the formula of chalcopyrite is CuFeS₂.
The molar mass of chalcopyrite   - 183.5 g/mol
The mass of Cu in 1 mol of chalcopyrite is - 63.5 g
When 183.5 g of chalcopyrite is mined, the mass of Cu obtained - 63.5 g
So if 63.g of Cu is needed mass of chalcopyrite required - 183.5 g 
Then to gain 370 g of pure Cu - mass of chalcopyrite needed -183.5/63.5 x 370
therefore mass of chalcopyrite to be mined - 1069.21 g