Why can you throw a full beer can further than an empty beer can?

Because of it's mass. But if you used the same amount of energy to throw both cans, the full can would not travel as far as the empty one.

New Thought:

Mass vs wind resistance, yes. But equal energy expended IN THE PRESENCE of an atmosphere will cause differing results dependant on the energy exerted. For instance: From minute amounts of energy up to x level, the empty can will travel further; at some point that situation reverses.