Question

What is the formula for aluminum oxide? What is the balanced equation for the formation of aluminum oxide?

Answer 1

Aluminum ions have a 3+ charge (`"Al"^(3+`) and oxide ions have a 2- charge (`"O"^(2-)`). Use the crossover rule to determine the formula, in which the size of the charge on one ion becomes the subscript on the other ion. `"Al"^(3+) + "O"^(2-)` `rarr` `"Al"_2"O"_3"`

The balanced chemical equation is:

`"4Al"("s") + "3O"_2("g")` `rarr` `"2Al"_2"O"_3("s")`

According to the equation, 4 moles of Al react with 3 moles of oxygen to produce 2 moles of aluminum oxide.