In an experiment to determine empirical formula of an oxide of vanadium a student weighed a dry empty crucible with its cover and determined its mass to be 41.761 g. After adding 0.314 g of vanadium metal into the crucible, the crucible and its content was heated in air for several minutes until all the content of the crucible was turned into ashes. The mass of the crucible and cover with its content after heating was determined to be 42.321g. Image attached for all of the questions it is asking.