How can i tell if a snowboard is light or heavy?

i want to buy my second board and i have no idea how to tell if its light cause i want to get a board for tricks which normally are lighter then others. my board now is way to heavy to get more then 2 feet of air. how do i tell if its light or heavy and if you have any reccomended boards that would be awesome im looking for 140-145cm and im a girl