acesulfame potassium and acesulfame K are the same exact thing, just named differently. The nickname for acesulfame potassium is "Ace-K", hence the K in acesulfame K.
Acesulfame potassium is an artificial sweetner. It's typically present in only very small quantities in foods, so it's probably not going to noticeably increase potassium levels.
No, acesulfame potassium is an entirely different molecular entity. However, many diet soft drinks that contain acesulfame potassium also contain aspartame as an artificial sweetener.
