Hola Stefan
I imagine you're referring to the set phrase "Eso es." meaning "That's it", when you are (sort of) corroborating what somebody else has said before. For example:
- Ah, vale, entonces, la farmacia está al final de esta calle a la derecha.
- Eso es.
- Ah OK, so, the chemist is at the end of this street on the right.
- That's it.
Here is a lesson on the pronouns ese, esa, esos, esas and the neutral eso. You'll see some examples there that may be helpful.
Saludos
Inma
