I believe those rounds that they launch in the video - the one with the blue heads - are propane bombs.
I believe that the Syrian rebels have indeed been using chemical weapons - I also believe that they (perhaps inadvertently) poisoned themselves and their neighbors. But I don’t think that that video in your link (interesting as it is!) shows proof of chemical weapon use.
http://rt.com/news/rebel-tunnel-damascus-chemical-940/ is more like it. There’s also a video on the page which is well worth our time.
Hope this proves helpful.