Hi All, During my study of thermodynamics these days I have a little confusion regarding the concept of state of a system and state functions. Here I begin what confuses me. We know temperature, pressure, volume, internal energy, entropy etc. are state functions. 1.I am wondering if a system at a particular state has some unique values of state functions? 2. What does it really mean by a state of a thermodynamic system? 3.Can two simillar systems at same state have different internal energy? OR Do internal energy is some special type of state function, which could indepedently clearifies what is the state of the system. 4. Is it possible for any process ,(to occur) where the initial and final state are different though the change internal energy is zero. In short the concept of state confuses me. Any help will be highily appreciated. REGARDS!!