Question

N2H4 is decomposed in a closed container according to this reaction: N2H4 → N2 + 2H2 . If the temperature is constant and the initial pressure of N2H4 is 800mm, what will the pressure in millimeters be after the decomposition to N2 + 2H2? Im having trouble with this problem because I don't see how can I find the temperature , wich is constant.

Answer 1

You don't need the temperature but you do need Keq unless, as I suspect, the author of the problem wants us to assume that the decomposition is COMPLETE. If that's the case, it is done this way.
.......N2H4 ==> N2 + 2H2
I......800......0.....0
C.....-800......800...1600
E.......0.......800...1600
So total pressure of the system will be 800 + 1600 = ? mm Hg.