Hess S Law

Using Hess's Law to find of

Target formation reaction:

Given data (standard enthalpies, kJ mol ):

• Combustion: , .
• , .
• , .

Apply Hess's law. For the combustion reaction: Rearranging for :

Substitute numbers: Compute stepwise:

Final answer:

Note: a previous arithmetic gave kJ mol ; the correct value from the above numbers is kJ mol .