Mute specific program
Here an answer from our friends over at SuperUser.
TL;DR: You can, but only with some extra software. They suggest AudioHijack Pro
AudioHijack is the only software I've found that can route application sound. If you are looking to capture/block sound from Chrome/Chromium you are out of luck though. AHP cannot handle that software yet due to the way Chrome's processes are spawned on the fly.