First law of thermodynamics and the conservation of energy explained
First law of thermodynamics , simply put, is a version of the law of conservation of energy. Thus, the first law of thermodynamics with the second and the third are just adapted for thermodynamic systems. Needless to say, they can be viewed differently regarding physics and chemistry. But, to talk about the first law of thermodynamics, first we need to see what the law of conservation of energy is all about.
The law of conservation of energy tell us that all the energy of an isolated system is constant. Thus, energy can be transformed but, in no way can it be created or destroyed.
The first law of thermodynamics refers to the change of the energy of a closed or an open system. Regarding the thermodynamic process, this law uses the key concepts of internal energy, system work and heat. When it comes to heat engines, this discussion can go on forever.
First law of thermodynamics and the conversation of energy explained
So, the first law of thermodynamics states that change of the energy of a closed system is equal to the amount of heat supplied to that system. That amount of heat minus the work done by the system is actually the change of the energy. Usually, the standard unit for these quantities is Joule, though some express them in BTU.
Typically, it is presented like this :ΔU=Q+W, even though the guy in the video below presents the ΔU as ΔE. Q is the heat; the power or the energy that enters the system. W stands for the work that the system does.
What we’re going through here is the simple basics of the first law of thermodynamics. The guy that uploaded the video on YouTube talks extensively about the law. In addition, he pinpoints some equations and tells us what to focus on. Check it out!