The isobaric process is a type of isoprocess that is thermodynamic. With it, the mass of the substance and one of its parameters (pressure, temperature, volume) remain unchanged. For an isobaric process, pressure is a constant.
The isobaric process and the law of Gay-Lussac
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 would be a constant. In other words, the volume of gas is directly proportional to its temperature at constant pressure. In Russian literature, the Gay-Lussac law is also called the law of volumes, and in English - the law of Charles.
The formula that the French physicist deduced for the isobaric process is suitable for absolutely any gas, as well as for liquid vapors, when the boiling point is reached.
Isobar
To depict such processes in the graphic 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 gas, and the second indicates pressure. When one of the indicators (temperature or volume) increases, the second indicator also increases proportionally, 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 a stove when atmospheric pressure is constant.
An isobar can exit a point at the origin of the coordinate axes.
Isobar gas operation
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. With increasing gas temperature, the particle movement becomes faster, and, therefore, the force with which the particles begin to bombard the walls of the vessel becomes stronger. If the temperature begins to drop, then the reverse process occurs. If one of the walls of the vessel is movable, then with a corresponding 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.
At school, this phenomenon is explained to children by the example of heating on a fire a glass flask filled with water and with a closed cork, when the latter flies out when the temperature rises. At the same time, the teacher always explains that the pressure of the atmosphere is constant.
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 speed of the body will remain equal to zero. When we talk about work in thermodynamics, then, first of all, we mean a change in internal energy, while in mechanical we are dealing with a change in 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 work to be done, p is the pressure is a constant when it comes to the isobaric process, O1 is the final volume, O2 is the initial volume. Therefore, when gas is compressed, then our work will be a negative value.
Thanks to the properties of gases discovered by Gay-Lussac at the beginning of the 19th century, we can move around in cars where isobaric operating principles are incorporated in the engine, enjoy the coolness that modern air conditioners give us on a hot day. In addition, the study of isobaric processes continues to this day that work to improve equipment used in the energy sector.