Temperature (t) and pressure (P) – two physical quantities interconnected among themselves. It is shown interrelation in all three aggregate states of substances. The majority of the natural phenomena depends on fluctuation of these sizes.
Instruction
1. Very close interrelation can be found between temperature of liquid and atmospheric pressure. In any liquid exists many small vials of air having the internal pressure. When heating in these bubbles saturated steam from the liquid surrounding it evaporates. All this proceeds until internal pressure does not become equal external (atmospheric). Then bubbles do not maintain and burst – there is a process which is called boiling.
2. Similar process happens also in solid bodies when melting or at the return process - crystallization. The solid body consists of crystal lattices which can be destroyed at a distance of atoms from each other. Pressure, increasing, works in the opposite direction – presses atoms to each other. Respectively, in order that the body melted, required more energy and temperature increases.
3. Klapeyrona-Mendeleyev's equation describes dependence of temperature on pressure in gas. The formula looks so: PV = nRT. Р – gas pressure in a vessel. As n and R – constants, becomes clear that pressure in direct ratio to temperature (at V=const). It means that the higher than P, the higher and t. This process is caused by the fact that when heating the intermolecular space increases, and molecules begin to move quickly in a chaotic order, so to hit more often against walls of a vessel in which there is a gas. Temperature in Klapeyrona-Mendeleyev's equation is taken usually in degrees Kelvin.
4. There is a concept of standard temperature and pressure: temperature is equal -273 ° Kelvin (or 0 °C), and pressure - 760 mm of a mercury column.