Sodium azide, a compound containing only sodium and nitrogen is used as a propellant for inflating airbags in some automobiles. A sample of sodium azide was weighed into crucible. The crucible was covered and heated until only sodium remained. The crucible was then cooled and reweighed. The following data were collected.

Mass of crucible and cover 28.887g
mass of crucible, cover and sodium azide 30.354g
mass of crucible, cover and sodium 29.406g
1- determine the empirical formula of sodium azide
2- write a chemical equation for the formation of Na and N2 from sodium azide