In the first picture, it looks like an unnotched Hopewell blade, but I agree that after seeing it from the edge that it looks like something else. I'm sure that some more knowledgeable than myself will help you out. Very nice piece.
Nice artifact. I'd call it a scraper also, but I'm thinking others might label it with another description. My cousin found a nice long notched point about the same size that looks to be made of the very same material at Red Rocks reservoir in Iowa.
Webster county Missouri Panther creek.
I have found several nice ones in same 30 foot circle there is a patch of small gravel in the middle every time ground is turned I will find a smoker there. Long occupation site stretches for a good 1/4 mile along the creek. Has a small rise that leads into steep hill gravel patch is in the middle of rise. The lower ground you will find 1 out of 20 that’s decent. On that small rise the workmanship is a step or two above lower ground. I have always wondered why the gravel was put there.
It's pretty big for a scraper and doesn't really look like the flint adzes I've seen from Missouri. (Many of them are thicker than that.)
I'd call it a biface.
You see that curvature on pieces for a couple of reasons, the most common is that it was just made on a thinner spall of chert that had some curve to it. They maximized the length and ended up with a slightly bent piece. It could also be that it's a preform and they were going to do something with the base. You often see an bottom edge that is going to be flaked (fluted, notched, etc.) angled with an edge below the plane of the middle of the blade. Beveled for lack of a better term. Here are two pictures of a fluted point base from my collection that shows it. (I don't think the original relic here was going to be a fluted point, but maybe notched like a Smith or something.)
Woodland hafted chipped (axe/adze..) Same exact shape and size as the same tool made of shell. Found on same site as shell adzes/axes where canoes were being made.