Suppose you have a bucket of H20 in the gas state which is isolated from the universe. Now the entropy is defined as the number of microstates. Now my question is what microstates to include in the calculation of the entropy. Parts of the H20 could condense into water and even ice. You could have H20 dissociating into H+ and OH-. When adding up all the microstates, do you add up all those possibilities, or just the microstates of the gas state?