Question

How do you solve the decomposition of aluminum oxide?

Answer 1

Aluminum Oxide decomposes to Aluminum metal and Oxygen gas.

- First, write down each compound:

`Al_2O_3\longrightarrow Al+O_2`

- Second, write the number of moles of each compound, so that we have the same amount of reactants as products. Here, it is important not to change the subscript of compound elements.

For example, let's start by adding a number 2 in front of the aluminum metal to balance:

`Al_2O_3\text{ }\rightarrow2Al+O_2`

So far, the amount of aluminum has been balanced but the amount of oxygen is unbalanced, so let's add a number 3 for the oxygen gas.

`Al_2O_3\text{ }\rightarrow2Al+3O_2\text{ }`

Now, to have the same amount of moles of oxygen on both sides, let's put a number 2 in the aluminum oxide:

`2Al_2O_3\text{ }\rightarrow2Al+3O_2`

Here, the amount of aluminum moles is unbalanced, so we add a number 4 for the aluminum metal to balance:

`2Al_2O_3\text{ }\rightarrow4Al+3O_2`

- This is the final balanced equation of decomposition of aluminum oxide:

`\begin{gathered} 2Al_2O_3\text{ }\rightarrow4Al+3O_2 \\ \end{gathered}`