There are a few ways to say "I am going to chemistry class" in Spanish, depending on the level of formality and nuance you want to convey:

Formal:

* Voy a clase de química. (This is the most straightforward and formal translation.)

* Me dirijo a la clase de química. (This literally means "I am going to the chemistry class," and emphasizes the direction of your movement.)

Informal:

* Voy a química. (This is a more casual way to say it, shortening "clase de química" to just "química.")

* Me voy a la clase de química. (This is a bit more informal and implies that you are leaving to go to class.)

Other options:

* Tengo clase de química. (This means "I have chemistry class," and implies you are going to it.)

* Voy a tener clase de química. (This means "I am going to have chemistry class," emphasizing the future aspect.)

The best option for you will depend on the context and who you are speaking to.