Aluminium is manufactured by electrolysis(electrolytic decomposition) of bauxite, Al2O3. How much aluminium can be obtained from 1kg of pure bauxite?
I'm not sure what you mean by "pure" bauxite. If that implies pure Al2O3 I don't think that is so but that must be what we are to assume.
You can get 2 mols Al for every mol of Al2O3. How many mols Al2O3 do you have in 1 kg?
1 mol.
No, you don't have 1 mol Al2O3 in 1 kg. Do you know what a mol is. A mol of Al2O3 is (in grams) 2*atomic mass Al + 3*atomic mass O = approximately 2*27 + 3*16 = about 54 + 48 = about 102 grams. Therefore, 1 kg = 1000g so in 1000g there are 1000/102 = about 9.8 mols Al2O3.
So 9.8 mols Al2O3, if it is pure Al2O3, will give you 9.8*2 = about 20 mols Al. Then grams Al = mols Al x atomic mass Al = ?grams. You can go through and clean up my approximations and come up with an answer close to what I have here.
To calculate the amount of aluminum that can be obtained from 1kg of pure bauxite, we need to consider the chemical reaction that takes place during the electrolysis of bauxite.
The chemical equation for the electrolysis of bauxite is as follows:
2Al2O3 + 3C → 4Al + 3CO2
From this equation, we can deduce that for every 2 moles of Al2O3, we will obtain 4 moles of aluminum (Al). Since the molar mass of Al2O3 is 101.96 g/mol (2 x 26.98 for Al + 3 x 16 for O), and the molar mass of Al is 26.98 g/mol, we can determine the number of moles of Al2O3 in 1kg of pure bauxite:
Moles of Al2O3 = (1kg / molar mass of Al2O3)
Moles of Al2O3 = (1000g / 101.96 g/mol) = 9.8032 moles (approximately)
Since every 2 moles of Al2O3 yield 4 moles of aluminum, we can calculate the amount of aluminum obtained:
Moles of Al = (moles of Al2O3 x 4 / 2)
Moles of Al = (9.8032 x 4 / 2) = 19.6064 moles (approximately)
Finally, we can convert moles of aluminum into grams:
Mass of Al = (moles of Al x molar mass of Al)
Mass of Al = (19.6064 x 26.98 g/mol) = 528.66g (approximately)
Therefore, from 1kg of pure bauxite, approximately 528.66g of aluminum can be obtained through the electrolysis process.