If I have two tanks of 1 liter filled with water at the same temperature and I pour it to a 2 liter tank, would the total entropy of the system change? Why? If I have a container which has a diaphragm at the middle, with the same gas (same temperature, same pressure etc.) from both sides of the diaphragm, at some moment the diaphragm is instantly removed, would the total entropy of the system change? Why?