The most common source of copper (Cu) is the mineral chalcopyrite (CuFeS2). How many kilograms of chalcopyrite must be mined to obtain 315 g of pure Cu?
You need x kg, where (using mol wts)
x * Cu/CuFeSO2 = 0.315
So look 'em up and do the math
typo
x * Cu/CuFeSO2 = 0.315 --remove the O to make it read
x * Cu/CuFeS2 = 0.315
oops. Guess I'm just used to typing SO2 in other places.
But I'm sure Janice caught my typo.
To determine the amount of chalcopyrite (CuFeS2) that needs to be mined to obtain 315 g of pure Cu, we need to consider the molar mass and stoichiometry of chalcopyrite.
1. Find the molar mass of Cu:
The atomic mass of Cu is approximately 63.55 g/mol.
2. Calculate the moles of Cu:
Divide the given mass of pure Cu (315 g) by the molar mass of Cu. This will give us the number of moles of Cu.
mass (g) = moles × molar mass (g/mol)
3. Use stoichiometry to find the moles of chalcopyrite (CuFeS2):
From the balanced chemical equation for chalcopyrite: CuFeS2 → Cu + FeS2, we can see that each mole of chalcopyrite gives one mole of Cu.
So the number of moles of chalcopyrite is equal to the number of moles of Cu.
4. Find the mass of chalcopyrite:
Multiply the moles of chalcopyrite obtained in step 3 by the molar mass of chalcopyrite (CuFeS2) to find the mass in grams.
5. Convert grams to kilograms:
Divide the mass of chalcopyrite in grams by 1000 to convert it to kilograms.
Let's calculate the answer step by step:
1. Molar mass of Cu = 63.55 g/mol
2. Moles of Cu = 315 g / 63.55 g/mol = 4.957 mol (rounded to three decimal places)
3. Moles of Chalcopyrite = 4.957 mol
4. Mass of Chalcopyrite = 4.957 mol × molar mass of CuFeS2
= 4.957 mol × (63.55 g/mol + 55.85 g/mol + 32.07 g/mol × 2)
= 4.957 mol × (63.55 g/mol + 55.85 g/mol + 64.14 g/mol)
≈ 4.957 mol × 183.54 g/mol
≈ 908.89 g
5. Mass of Chalcopyrite in kilograms = 908.89 g / 1000 = 0.909 kg (rounded to three decimal places)
Therefore, approximately 0.909 kilograms of chalcopyrite (CuFeS2) must be mined to obtain 315 g of pure Cu.