Answer to Question #21954 in Inorganic Chemistry for Khadijah

Question

Aluminum oxide is decomposed using electricity to produce aluminum metal. Hm grams of aluminum metal can be produced from 100.0g of Al2O3?
2Al2O3--> 4Al+ 3O2

Answer 1

If 2Al2O3 --> 4Al+ 3O2;
So, first of all we can find amount of substance of Al2O3:
n(Al2O3) = m(Al2O3)/M(Al2O3);
M(Al2O3) = Ar(Al)*2 + Ar(O) *3;
M(Al2O3) = 27*2+16*3 = 102 g/mol;
n(Al2O3) = 100.0 g / 102.0 g/mol = 0.98 moles
by the reaction equation the substances relate as:
n(Al2O3) : n(Al) = 2 : 4;
So n(Al) = n(Al2O3)*4/2 = 1.96 moles
And the mass of Al will be:
m(Al) = n(Al) * M(Al);
M(Al) = Ar(Al) = 27 g/mol
m(Al) = 1.96 mol * 27 g/mol = 52.92 g