Question

How to balance Al + O2 = Al2 O3

Answer 1

\[?Al + ?O_2 => ?Al_2O_3\]
Start by putting 2 in front of the Aluminum.
\[2Al+ ?O_2 => ?Al_2O_3\]
To get the right number of Oxygen on the right we need to times the left OXygen by 3/2.
\[2Al+\frac{3}{2}O_2 => ?Al_2O_3\]
To get a non fractional answer we need to times the whole thing by 2:
\[4Al+3O_2 => 2Al_2O_3\]