Internal Energy Change: Homework Solutions

[Teemo]

Homework Statement

Internal Energy Change

Homework Equations

N/A

The Attempt at a Solution

If internal energy change equals enthalpy change, then I am looking for the reaction which has the enthalpy change closest to zero. I know it cannot be A, as the formation of water is highly exothermic. I know it cannot be C, as the vaporization of water is highly endothermic. This leaves B and D. I think it should be D, as it is a decomposition. I find that the breaking of bonds of halogens in B to seem endothermic.

 

[Chestermiller]

Which reaction has the smallest volume change if carried out at constant temperature and pressure?