Aluminium can be produced by the thermal decomposition of aluminium oxide. What mass of aluminium would be produced from 3.5kg of aluminium oxide?

Aluminium oxide: Al2O3.

Molecular mass (approx.)=27*2+3*16=102
Aluminium:
Al
Molecular mass=27.

Write down the equation:
2Al2O3 -> 4Al + 3O2 (electrolysis)

So
2 Al2O3 molecules -> 4 Al molecules.
2*102 Al2O3-> 4*27 Al
204 : 108

Use proportion to solve for the final answer (substitute the exact atomic masses)

There is nothing wrong with the solution by MathMate of this hypotehtical question. However, I just don't believe Al2O3 will decompose thermally to Al/

Quite right Dr.Bob. Thank you for the note.

It just doesn't decompose like that. Carbon is required to reduce the oxide.
Namely
2Al2O3+3C -> 4Al + 3CO2
The electrolysis part is more to help prevent the formation of CO.
However, as you said, the ratio of Al and Al2O3 does not change.

To find the mass of aluminum produced from the thermal decomposition of aluminum oxide, we need to use the balanced chemical equation for the reaction.

The balanced equation for the thermal decomposition of aluminum oxide is:
2Al2O3 → 4Al + 3O2

From the equation, we can see that for every 2 moles of Al2O3, we obtain 4 moles of Al.

To find the molar mass of Al2O3:
1 mol of Al = 26.98 g/mol
3 mol of O = 16.00 g/mol

Therefore, the molar mass of Al2O3 is:
2(26.98 g/mol) + 3(16.00 g/mol) = 101.96 g/mol

Now, we can calculate the number of moles of Al2O3 in 3.5 kg (3500 g):
moles of Al2O3 = mass (g) / molar mass (g/mol)
moles of Al2O3 = 3500 g / 101.96 g/mol = 34.28 mol

Since the stoichiometry of the reaction tells us that 2 moles of Al2O3 produce 4 moles of Al, we can calculate the number of moles of Al produced:
moles of Al = moles of Al2O3 × (4 moles Al / 2 moles Al2O3)
moles of Al = 34.28 mol × (4/2) = 68.56 mol

Finally, we can find the mass of Al produced from the number of moles:
mass of Al = moles of Al × molar mass of Al
mass of Al = 68.56 mol × 26.98 g/mol ≈ 1849.287 g or 1.849 kg

Therefore, approximately 1.849 kg of aluminum would be produced from 3.5 kg of aluminum oxide.