Why are gases unpredictable?
A gas is a system of particles that are very mobile and are (relatively) free to move around the system. This freedom to diffuse within the system is a result of Brownian motion (particles collide in a random manner – although it is possible to predict the behaviour/collisons of a few particles it is not for possible for the millions of particles that might occupy 1 cm^3). The product of random collisions is unpredictable, in the same way rolling a dice can not have its outcome predicted. However if the system is considered a single volume and not a large collection of particles then it is becomes possible to predict it behavior but not in terms of particle collisions, particle theory and brownian motion. If temperature and number of particles in a gas are kept constant, then the pressure of the gas will increase if the volume is decreased (hence inversely proportional). The entropy/disorder of the gas will decrease if the volume increases and everything else is kept constant (inversel
