[Dirac]

The ammonium nitrate suffers a transformation to 125.5 ° C and 1 atm, and other one to 135.0°C and 1,000 atm of pressure. The stable form to high temperatures, has an average volume of 0.0126 cc/g major that another modification for the interval of pressure studied. Calculate the enthalpy of the transition.

I believe that my result is erroneous. The enthalpy is very low and the result that appears in the text is of approximately 1000 calories. I ask you if I committed a mistake to indicate it to me.

PD: I'm sorry for my English. It is not my mother tongue

[Enthalpy]

¡Hola Dirac!

Without the refinements of integral and log, I get, all in SI units:

80g/mol hence 1.01*10^-6 m³/mol volume change
999*10⁵ Pa pressure change between both temperatures
10K temperature difference around mean 403K

from which Clausius-Clapeyron bring me:

4066J/mol, near to 1000 cal/mol

[Dirac]

Thank you. I have to realize that the logarithm must not multiply. Your solution of the problem looks like to me a good alternative. Greetings