Introduction To Charlie's Law

- May 22, 2020-

Introduction to Charlie's Law

For a gas of a certain mass, when the volume remains unchanged, its pressure p changes linearly with temperature t, that is, p = p0 (1 + apt) where p0, p are the pressure of the gas at 0 ℃ and t ℃ It is the pressure-temperature coefficient of a constant volume of gas. Experimentally determined that ap≈1 / 273 ° of various gases.

Experiments show that for air, at room temperature and atmospheric pressure, the above three laws are approximately correct. The higher the temperature, the lower the pressure and the higher the accuracy. Conversely, the lower the temperature, the higher the pressure and the greater the deviation. (Taking air as an example, at 0 ° C, if the pressure is 1 atm, the volume is 1 liter, that is, pV is equal to 1 atm · l. When the pressure is increased to 500 and 1000 atm, the pV product increases to 1.34 and 1.99 atm. , There are obvious differences.) In addition, the av and ap of the same gas vary with temperature and are slightly different; the av and ap of different gases are also slightly different. The higher the temperature and the lower the pressure, the smaller the difference. At normal temperature, the limit of pressure tends to zero. For all gases, av = ap = 1 / 273.15 °.