In the reaction _ al + 302 + 2al2o3 , what coefficient should be placed in front of the al to
balance the reaction?

The coefficient is 2

Explanation:

The balanced equation is;

2Al(s) + 3O₂(g) → 2Al₂O₃(s)

The law of conservation of mass requires that all chemical equations be balanced for the mass of reactants and that of the products be the same.Balancing chemical equations involves putting coefficients on reactants and products. It makes sure that the number of atoms of each element is equal on either side of the equation. In this case, putting a coefficient 2 on Aluminium makes the equation balanced.It results in 2 Aluminium atoms and 6 oxygen atoms on either side of the equation.