Question

How many moles of oxygen are produced when 26.5 mol of aluminum oxide are decomposed?

Answer 1

Reaction for the decomposition of the Al₂O₃ is ⇒

2Al₂O₃ ----------→ 4Al + 3O₂

From the reaction,
2 mole of the Aluminium oxide produces 3 mole of the Oxygen.
∴ 1 mole of the Aluminium oxide produces 3/2 mole of the Oxygen.
∴ 26.5 mole of the Aluminium oxide produces (3/2) × 26.5 mole of the Oxygen. = 39.75 moles.


Hence, the numbers of the moles of the oxygen produced is 39.75 moles. 



Hope it helps. :-) 

Answer 2

We need to write a balanced equation to solve this probelm

2 Al2O3 = 4 Al + 3 O2


If 26.5 mol of aluminum oxide are decomposed,

the number of moles of O2 that will be produced 

= 26.5x3/2

= 39.75