and i don't just mean "because it's google and google is an ad company". what specifically is it sending to some internet server that firefox doesn't? both the firefox and address bars send what you type into them to a search provider. as near as i can tell, firefox's committment to privacy is to say "we protect your privacy" while doing all the same stuff that chrome does.
Firefox blocks a bunch of tracking by default. Chrome requires the user to take action to prevent that tracking. I also recall Chrome leaking hardware UUIDs some years back when Chromium did not meaning Google added code to cause that. I think that has been fixed for awhile since I don't immediately find info about it.