That's incorrect! When two or more substances combine to form one new simpler substance, it's not a chemical reaction. It's actually the opposite.

Here's why:

* Chemical reactions involve the formation of new substances with different chemical properties than the original substances.

* Decomposition reactions are a specific type of chemical reaction where a complex substance breaks down into simpler substances.

Therefore, the process you're describing is decomposition or a breakdown reaction, not a combination reaction.