"The standard molar enthalpy of combustion of propanoic acid is -1527.2 kJ mol-1. Given that the standard molar enthalpy change of formation of water is -285.5 kJ mol-1 and that of carbon dioxide is -393.5 kJ mol-1, construct a Hess's Law cycle and calculate the standard molar enthalpy change of formation of propanoic acid?"
Seriously there are so many ways and different routes people have answered it and its really confused me
Is there anyone who can give me the one correct equation, correct pathway and correct equation to work this out?
Seriously is there anyone who can help me with this question watch
- Thread Starter
- 21-01-2015 21:33
- 21-01-2015 22:02
Remember; enthalpy change is a state functions it is not path dependent.
So, the formation of the propanoic acid followed by the combustion of the propanoic acid, is the same as going straight to the products of the combustion (namely carbon dioxide and water).
Look the equation of the combustion, work out molar ratios.
Then calculate the answer.