Question

Aluminum can react with oxygen gas to produce aluminum oxide (`Al_2O_3`). What type of reaction is this?

Answer 1

This is a synthesis reaction.

Explanation:

We're given that aluminum (`"Al"`) can react with oxygen gas (`"O"_2`; don't forget it's diatomic!) to produce aluminum oxide (`"Al"_2"O"_3`).

The balanced chemical equation for this reaction is

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

A reaction in which two or more reactants combine to form only one product is called a synthesis reaction.

Here, there are two reactants (`"Al"` and `"O"_2`) combining to form one product, `"Al"_2"O"_3` (key word one), so this is a synthesis reaction.

Here is a useful image with more synthesis reaction examples: