OMG! Chemistry! Help! Homework!?

Question

Copper is extracted from the ore, Chalcopyrite, CuFeS2. How many kilograms of a 0.862% chalcopyrite ore will be necessary to produce 1.00kg of pure copper? The percentage of copper in chalcopyrite needs to be known to work this problem.

I don't know what to do with the 0.862%. Please help me.

Answer 1

First, find % copper in CuFeS2:

63.55/[63.55 + 55.85 + (2 x 32)] x 100% = 34.6%

Find Kg of ore needed for 1 kg copper (if pure CuFeS):
(Note: we can see the answer will be about 3 Kg merely by looking at the % Cu value)

1.00kg Cu x 1 kg CuFeS2/0.346kgCu = 2.89Kg CuFeS2

Now, we were told it was a 0.862% ore; so, that means there is only 0.862% of The compound CuFeS2 in the ore (the rest is rock/unusable material). Since we can see that less than 1% of the ore is CuFeS2, the weight of ore required will be over 100 times as much as if it were pure CuFeS2.

Here's how to calculate it:

2.89 Kg CuFeS2 x 1Kg "ore"/0.00862Kg CuFeS2 =

335kg of "ore"

Answer 2

HNO3 + ZnO = ZnNO3 + OH- pascals measure pressure. kelvin measure temperature (K= degrees celsius +273). dm could be decimeter?? we don't use that one... dm3 would be a volume, g/dm3 would be a density (mass/volume). Mol = mole. A mole is the heart of chemistry, so get used to converting to and from it using Avogadro's number (6.022x10^23). mole/dm3 would be asking how many moles of a substance are in each dm3. Chemistry can be very overwhelming at times, so make sure and pay attention in class and study hard until you know what to expect from your teacher. Good luck!