Van't Hoff Approach to Finding ∆H and ∆S

[ampakine]

Heres the question:
[PLAIN]http://img194.imageshack.us/img194/9042/vanthoff.png
and here's the Van't Hoff equation (the form I like to use):
[PLAIN]http://img703.imageshack.us/img703/1577/vtequation.png
I'm a bit confused about what's going on here. I see the formula includes ∆H^o, meaning the enthalpy change for 1 mole of reactant at 298K. Does that mean to use this formula T1 always has to be 298K? In other words to get the ∆H^o for the reaction would I just plug 298K into T1 and 4.25 x 10^-7 into K_T1 then plug any other pair of values from that table into T2 and K_T2?

 

[mrmiller1]

The ∆H is always assumed to be constant with temp in this equation (standard enthalpy change), which is an obvious downside to the relation. If you derive it from
(d ln(K)) / (d 1/T) = -∆H^o/R you will find that from the integration.