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