Yes. Its normal. It a vent tube, it vents fumes out of the tank and away from you. I would find a replacement cause moisture can get into your tank easily without it. They are very very cheap at can be found at any online/ or store that sells dirt bike stuff.
Or you can make your own if you have any rubber tubes around the house/garage.
Its fine dont worry about it, its a tank breather, the tank cap has a kind of one way valve in it to stop fuel coming out.
But lets air in so that the tank does not become vacuumed and stop the fuel from reaching the carb.