Bauxite ore contains aluminum oxide Al2O3(s) which is decomposed using electricity to produce aluminum metal and oxygen gas. What mass of aluminum metal can be procuced from 155g of aluminum oxide?

Answer 1

balance the equation

2Al2O3>>4Al + 3O2

figure the moles of aluminum oxide in 155g

so you get twice those moles of aluminum.
Covert that to grams.

Answer 2

155g of Al203, molar mass is 101.96g/mol, number of moles is 1.52.
ration 2to4 2x=4(1.52)=3.04 moles.
mass = molar mass of Al is 26.98 times number of moles 3.04 = 82.019