Question

Chalcopyrite (CuFeS2) is a principal mineral of copper. Calculate the number of
kilograms of Cu in 3.71 X 103kg of chalcopyrite.

Answer 1

Calculate the molar mass of chalcopyrite by adding up the individual molar masses of all the atoms.

Multiply 3.71 X 10^3 kg by 1000 to get grams of chalcopyrite. Divide (mass of chalcopyrite in g) by the molar mass you calculated in the first step.

At this point you have moles of chalcopyrite. Since 1 mole of chalcopyrite has 1 mole of Cu, moles chalcopyrite = moles Cu.

Now you have moles Cu. Multiply by the molar mass of Cu to get grams Cu. Since the problem wants Cu in kg, divide by 1000.