What is the first law of thermodynamics?
The first law of thermodynamics is also known as the Law of Conservation of Energy. States that energy cannot be destroyed or created; It is preserved in space and must end somewhere, even if the molds change. This includes studying system work, heat and energy. Thermal engines often evoke discussions about the first law of thermodynamics; However, it is considered one of the most basic natural laws.
As soon as people immerse themselves in the study of the first law of thermodynamics, they immediately begin to analyze and calculate the equation associated with the law: ΔU = Q - W. In the alternative, the equation ΔU = Q + W is sometimes used. The only difference is that they calculate them work on the system, instead of working by the system. In other words, the work is positive when the system works on its surrounding and negative when the surroundings work on the system.
When studying physics, there is a common example that involves adding heat to gas in a closed system. The example continues by expanding this gas so that it works. It can be visualized as a piston pushes down or exert pressure on the engine in the engine with internal combustion. The work is therefore carried out by the system. In the alternative, when studying chemical processes and reactions, it is typical of studying the conditions in which work is carried out in the system.
Standard unit for calculating the first thermodynamic law is Joules (J); However, many people who study the law also perform their calculations in terms of calories or British thermal units (BTU). Sometimes it is useful to calculate protection with real numbers, allowing people to see how the law works. If the engine does 4,000 J work in its surroundings, the internal energy is reduced by 4,000 J. If it also releases 5,000 J heat when it works, then the internal energy is reduced by another 5,000 J. As a result, the internal energy of the system reduces a total of -9 000 J.
In an alternative calculation, if the system does 4,000 J work in its surroundings and then absorbs 5,000 J of heat from its surroundings, the result is different. In this case, 5,000 J of energy goes and 4,000 J energy goes out. The total internal energy of the system is therefore 1,000 J.
Finally, negative work or work done on the system around the system can be illustrated through calculations concerning the first thermodynamic law. For example, if the system absorbs 4,000 J as the surroundings at the same time the 5,000 J or works on the system, another result will be seen. Because all energy flows into the system, the total internal energy jumps up to 9,000 J.