The most common source of copper (Cu) is the mineral chalcopyrite (CuFeS2). How many kilograms of chalcopyrite must be mined to obtain 240. g of pure Cu? Express your answer to three significant figures and include the appropriate units.

0.693kg of CuFeS2 is needed to produce 240 grams of Cu.

Explanation:

In 1 mole of CuFeS2 is associated 1 mole of Cu.

Molar mass of CuFeS2 = 183.5 g/mol

Molar mass of Cu = 63.5g/mol

No of moles of copper present in 240g of chalcopyrite = 240/63.5 = 3.779moles

we know

1 mole of Cu → 1 mole of CuFeS2

in 3.779 moles of Cu → 3.779 moles of CuFeS2

3.779 moles of CuFeS2 = 3.779 * 183.5 = 693.45grams

CuFeS2 in kg = 0.693kg