Here's a breakdown:

* 3H₂: This represents three molecules of hydrogen gas (H₂).

* N₂: This represents one molecule of nitrogen gas (N₂).

* 2NH₃: This represents two molecules of ammonia (NH₃).

* -->: This indicates that the reactants on the left side of the arrow react to produce the products on the right side of the arrow.

In simpler terms: This equation shows that when three molecules of hydrogen gas react with one molecule of nitrogen gas, they combine to form two molecules of ammonia.

This reaction is very important because it's how ammonia is produced industrially. Ammonia is used in fertilizers, explosives, and many other products.