Internal energy is the total energy contained within a system. It includes the kinetic energy of the particles and the potential energy stored within the bonds between particles.
Internal energy is directly proportional to temperature. As the temperature of a system increases, so does its internal energy. This is because an increase in temperature causes the particles within the system to move faster, thus increasing their kinetic energy.
A PV diagram is a graphical representation of the relationship between pressure and volume in a system. It is significant because it allows us to visualize and understand the changes in pressure and volume that occur during different processes, such as isothermal, adiabatic, and isobaric processes.
The change in internal energy can be calculated by finding the area under the curve on a PV diagram. This can be done by breaking the area into smaller shapes, such as rectangles or triangles, and using their respective formulas to find their individual areas. The sum of all these areas will give the change in internal energy.
The first law of thermodynamics states that energy cannot be created or destroyed, only transferred or converted from one form to another. This applies to internal energy, as it can be transferred into or out of a system through various processes, but its total amount remains constant.