Internal Energy

[Abigail Yap 2K]

Hello,

I am having difficulty understanding the concept of internal energy and its importance in determining enthalpy. Can someone please clarify this for me? Thanks!

[Katie Blann 1E]

Internal energy is the energy contained within a system. It accounts for the energy change in the systems internal state. So, that state can be changed by transfers of matter, heat or by doing work.
Enthalpy is equal to the internal energy of the system plus the product of pressure and volume.

[Juanyi Tan 2K]

Just want to add on. Internal energy is the sum of the kinetic and potential energies of the particles that form the system and enthalpy is defined as the heat absorbed or released when a system does work. That is way the enthalpy is given by the equation H (enthalpy) = U (internal energy) + PV (work)