Change in Volume on Activation, AV

Such effects are confined to reactions in solution, and are of fundamental importance in mechanistic studies. As with entropy changes, there are several factors which can make a substantial contribution to the overall AV.  

Question. The following data give the dependence of rate constant on pressure 

One of the main difficulties in this problem is the matter of units  

A positive pressure effect means that k increases as pressure increases, and is negative. 

---