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Boyles Law states that, for any sample of gas, its pressure multiplied by the volume it occupies is a constant providing the temperature remains constant. (ie pV = constant). This is always true for perfect gases, for which pV = nRT by definition.
How can deviations from ideal behaviour be compensated for in our model of the situation? Recall that our model produced p.Vm = RT (ideal gas equation).
If we consider a mixture of gases in a container, then they each exert a pressure on the walls of that container. ie: one gas provides a component of the total pressure, and another gas provides another component.
Thus far we have concentrated on perfect gases. It is important to appreciate that no gas actually is perfect – they all deviate from ideal behaviour to some degree.
The mean free path is, as the name suggests, the average distance a molecule can go before colliding with another molecule.
Experimentally we find that the most probable speed increases as the temperature is increased, or as the moleclular mass is decreased.
We treat the molecules as hard spheres (of diameter d) – like pool balls. For two molecules to collide, their centres must come within a distance d of each other.
The root mean square speed, crms, can be related to macroscopic properties.
The kinetic model is based upon 3 assumptions