A box containing a piece of wood and enough air to burn the wood is measured and found to have a mass of 1.5 kg. If the wood is burned and none of the smoke, ashes, or hot gases are allowed to leave the box, then how will the mass of the box compare to the mass before burning? Will it be more, less, or the same?

wait what grade is this for

the reaction mixture contains some ammonia, plus a lot of unreacted nitrogen and hydrogen. the mixture is cooled and compressed, causing the ammonia gas to condense into a liquid. the liquefied ammonia is separated and removed. the unreacted nitrogen and hydrogen are then recycled back into the reactor .