Calculate \DeltarH0 and \DeltarU0 for Hydrogenation of Ethyne to Ethene at 348 K

[winterwind]

Homework Statement

Calculate \Delta_rH⁰ and \Delta_rU⁰ at 348 K for the hydrogenation of ethyne (acetylene) to ethene (ethylene) from the enthalpy of combustion and heat capacity data in Tables 2.5 and 2.7. Assume the heat capacaties to be constant over the temperature range involved.

\Delta_fH⁰ of ethyne = +226.73 kJ/mol
\Delta_p,mC⁰ of ethyne = 43.93

\Delta_fH⁰ of ethene = +52.26 kJ/mol
\Delta_p,mC⁰ of ethene = 43.56

Other relevant data in the tables are also given, such as Enthalpy of fusion, enthaply of combustion, molar heat capacity, Benson thermochemical groups, of various molecules, including water, oxidation, hydrogen gas, carbon dioxide gas, ethane, ethene, and ethyne.
I only included the above because I think I would need to use those for sure. The other data can be easily found.

Homework Equations

Hess's Law
Kirchhoff's Law

The Attempt at a Solution

I might try combining equations to arrive at the right equation (Hess's Law). Maybe Kirchoff's Law to find the values at 348 K? What is meant by \Delta_rU⁰? Is this the change in internal energy? How does it relate to enthalpy (fusion, heat capacity, etc.)?

Thanks!

EDIT: I only need help with question in post #2 now. I figured out the other parts already.

 

[winterwind]

I just need help with this part of the probelem now:

Calculate \Delta_rU⁰ at 298 K for the hydrogenation of ethyne (acetylene) to ethene (ethylene) from the enthalpy of combustion and heat capacity data in Tables 2.5 and 2.7. Assume the heat capacaties to be constant over the temperature range involved.

I figured out the other parts of the problem. I am still not sure of the relationship between \Delta_rU⁰ and enthalpy values.

 

[limonysal]

Hi winterwind,
I'm also working on this problem for a homework due this week...which makes me wonder...

Anyway, I found in my notes that \DeltaH=\DeltaU+\Deltan_gasRT.

I hope this helps :)