Describe the differences between internal energy and enthalpy.

Internal energy is the sum of all the kinetic and potential energies of the particles in a system. Enthalpy, on the other hand, is the sum of the internal energy and the product of pressure and volume.

Internal energy is a measure of the total energy of a system, including the energy associated with the motion and position of the particles within the system. It is a state function, meaning that it depends only on the current state of the system and not on how it got there. Internal energy can be changed by adding or removing heat or work from the system.

Enthalpy, on the other hand, is a measure of the heat energy that is released or absorbed during a chemical reaction or physical change. Enthalpy is also a state function, meaning that it depends only on the current state of the system. Enthalpy is often used to describe the heat of a reaction, which is the difference between the enthalpy of the products and the enthalpy of the reactants.

One key difference between internal energy and enthalpy is that enthalpy includes the energy associated with pressure and volume changes, while internal energy does not. This means that enthalpy is a more useful measure of the energy changes that occur during a reaction or process that involves changes in pressure or volume.

In summary, internal energy and enthalpy are both measures of the energy of a system, but enthalpy includes the energy associated with pressure and volume changes, making it a more useful measure for describing energy changes during chemical reactions and physical processes.