Factors affecting liquid pressure

Hi, may I ask what are the factors that affect liquid pressure?

>>9
The ideal gas law might provide some qualitative insight into how a liquid behaves as a function of temperature and pressure, but I think it's quantitatively, very wrong.

1st reason: liquids have tremendous interparticle interactions

Ideal gases are assumed to be non interacting particles, but even for some interacting gases, one can make adjustments with the van der waals equation.  For liquids, the particle interactions would completely dominate the equation, and I highly doubt the accuracy of this equation in this limit.
http://en.wikipedia.org/wiki/Van_der_Waals_equation

2nd reason: bulk modulus (how amenable something is to compression) doesn't fit.

Ideal gases have a bulk modulus that is conveniently, just P.  So at atmospheric pressure, this comes out to ~ 10⁵ Pascals.  Water, however, has a bulk modulus of ~ 10⁹ Pascals.

To put it in simpler terms: a helium balloon will halve its size when subjected to twice the pressure, but a glass of water will look the same.