How to calculate the delta H of solution?

Question

NH4NO3 - ammonium nitrate

1.15g of powdered anhydrous ammonium nitrate was rapidly dissolved in 100.0ml of water

calculate the delta H solution for ammonium nitrate

any help would be good thanks, i just need to know how to do it

thanks in advance

Answer 1

NH4NO3 (s)  -->  NH4)+ (aq)  &  NO3- (aq)

the task is to find a reference that has all three dHf for those above, ...

& then to do a products - reactants:

[Hf NH4)+ (aq)  & dHf NO3- (aq)] - dHf NH4NO3 (s) =

[-132.5  & (-206.6 )] -  (-365.6) = +26.5

Your answer is dH of solution = + 26.5 kJ/mole

(& expect that last digit to vary from text to text)

When my text did not have aqueous nitrate, I used :

http://chemistry.about.com/library/weekl...