Isobaric process

The isobaric process is a kind of isoprocess, which is thermodynamic. With it, the mass of the substance and one of its parameters (pressure, temperature, volume) remain unchanged. For the isobaric process, the constant is the pressure.

The isobar process and the Gay-Lussac law

In 1802, thanks to a series of experiments, the French scientist Joseph Louis Gay-Lussac deduced the regularity that at constant pressure the ratio of the volume of gas to the temperature of the substance itself of a given mass will be a constant value. In other words, the volume of gas is directly proportional to its temperature at constant pressure. In Russian literature, the law of Gay-Lussac is also called the law of volumes, and in English, the law of Charles.

The formula that the French physicist derived under the isobaric process is suitable absolutely for any gas, as well as for vapors of liquids, when the boiling point is passed .

Isobar

To display such processes in the graphical version, an isobar is used, which is a straight line in a two-dimensional coordinate system. There are two axes, one of which is the volume of the gas, and the other is the pressure. When one of the indicators (temperature or volume) increases, the second indicator proportionately increases, which ensures the presence of a straight line as a graph.

An example of an isobaric process in daily life is the heating of water in a kettle on the stove, when the atmospheric pressure is unchanged.

The isobar can leave the point at the origin of the coordinate axes.

Operation in the isobaric gas process

Due to the fact that the gas particles are in constant motion, the gas accordingly constantly exerts pressure on the wall of the vessel in which it is enclosed. As the temperature of the gas increases, the motion of the particles becomes faster, and, consequently, the force with which the particles begin to bombard the walls of the vessel becomes stronger. If the temperature starts to drop, then the reverse process occurs. If one of the walls of the vessel is movable, then, with the proper proper increase in temperature, when the pressure force on the wall of the gas vessel from the inside becomes higher than the resistance force, the wall begins to move.

In school, children are explained this phenomenon by the example of heating a glass bulb filled with water and a closed stopper on a fire, when the latter flies out when the temperature rises. At the same time, the teacher always explains that the pressure of the atmosphere is invariable.

In mechanics, the motion of a body relative to space is considered, and thermodynamics studies the motion of parts of a body relative to each other, while the velocity of the body remains zero. When we talk about work in thermodynamics, then, first of all, we mean the change in internal energy, while in mechanical we are dealing with a change in the kinetic energy. The work of gas in the isobaric process can be determined by the formula in which the pressure is multiplied by the difference between the volumes: initial and final. On paper, the formula will look like this: A = pX (O1-O2), where A is the job being done, p is pressure is a constant value when it comes to the isobaric process, O1 is the final volume, O2 is the initial volume. Therefore, when the gas is compressed, the work will be negative.

Thanks to the open Gay-Lussac in the early 19th century, the properties of gases we can move on cars where the engine is based on isobar principles of work, enjoy the coolness, which on a hot day we are given modern air-conditioners. In addition, the study of isobaric processes is still going on, that it is necessary to improve the equipment used in power engineering.