The actual time in the air would be 5.9 hours (probably longer, since spec sheet range numbers usually are at economy settings, but speed is quoted at 75%). Two fuel stops, however, are going to add 1.5 hours (45 minutes per stop, which is conservative) for a total of 7.3 hours.
A normal lens or normal prime is a lens with a focal length about equal to the diagonal size of the film or sensor format, or that reproduces perspective that generally looks natural to a human observer under normal viewing conditions.
There are two main types of lenses: convex and concave. Convex lenses often get all the credit. They are the type of lens responsible for magnification and are the most common lens used in photography and other common applications. Concave lenses, though, serve an important role as well. A concave lens is any lens that has an inward curve in the middle.