No, chemical weathering doesn't always involve water. While water is a major player in many chemical weathering processes, there are other ways for chemicals to break down rocks.

Here are some examples of chemical weathering without water:

* Oxidation: This process involves the reaction of oxygen with minerals in rocks. For example, iron in rocks can react with oxygen to form iron oxide, which is rust. Rust is weaker than the original rock, making it more susceptible to further weathering.

* Hydrolysis: This is a reaction between minerals in rocks and acidic gases in the atmosphere, like sulfur dioxide or carbon dioxide. These gases can dissolve in rainwater, forming weak acids that can react with minerals in rocks.

* Biological Weathering: Some organisms can contribute to chemical weathering without water. For example, lichens produce acids that can break down rocks.

However, it's important to note that water is crucial for many chemical weathering processes. It acts as a solvent and a transport medium, allowing for the movement of ions and chemicals that contribute to the breakdown of rocks.

So, while water isn't always present in chemical weathering, it is a significant factor in many cases.