[galvanichell]

If given  :delta: H ^o _rxn how do I calculate  :delta: E ^o _rxn? Am I right to think that I use H = E + pV for this?   All that is given is  :delta: H ^o _rxn and the balanced reaction. I'm not sure how to go about calculating it.

[galvanichell]

Here is an example of one of the questions in this format. Maybe this will help you to understand what I do not, so you can explain it to me. Any help would be great.

The standard enthalpy of reaction,  :delta: H^o_rxn for C₂H₂(g) + 2H₂(g) C₂H₆(g) is -311.5 kJ mol^-1. Determine the value of  :delta: E^o_rxn for this reaction.