Is there any difference between state function and state variable? I saw the term 'state variable' in Silbey's Physical Chemistry (4th edition). But it seems the term 'state function' is more commonly used. I believe state variables only refer to those that we can directly manipulate, like pressure, temperature, amount, volume, composition, surface area, E field, B field, gravity, etc. State functions are functions of state variables, like H, U, A, S, G, etc. So a state variable is also a state function, e.g. p is a function of V, T, and n. But H, U, A, S, G are not state variables.
Am I right???