So far we have used laws of balance and expressions for processes, i.e., for flows, source rates and production rates, in their integral forms; in other words we have written and applied the appropriate equations for an entire body. Now we will justify and derive the proper equations of balance of mass, entropy, and momentum, for continuous bodies. This will prepare the ground for theories of thermodynamics of continuous processes which build upon these laws of balance and expressions for constitutive laws in analogy to how we have proceeded before in this book.