Can you use floor tile on a wall?

Yes, you can use floor tile on the wall. It can be heavy, but if you use a high quality latex fortified thin set (NOT mastic) you should have no issues. It also should be put onto cement board for best results. In the past using floor tile on the wall was an issue because trimpieces were not easily available. With trends changing, you are seeing more with bullnose and you can always use ceramic trim like schulter. Now, you CANNOT put wall tile on the floor. They are often made with white clay and other more bridle ingredient's. Check the box, it will tell you what it is rated for.