The most common source of copper (Cu) is the mineral chalcopyrite (CuFeS2). How many kilograms of chalcopyrite must be mined to obtain 315 of pure ?

Answer 1

of pure WHAT?
Here is a site that gives you the step by step procedure to use for stoihchiometry problems.

Answer 2

Here's the link.
http://www.jiskha.com/science/chemistry/stoichiometry.html

Answer 3

0.852