9.19 Finding standard entropy of water

[Kyra Dingle 1B]

Can someone explain further why when determining the standard entropy of water at 85 degrees C you need to find the entropy change when heating the reactants to boiling point and the change when cooling the products back down to 85 and then finally add those changes with the standard entropy at 100 degrees C? I am having trouble with understanding how this concept works

[Julian Krzysiak 2K]

Because Entropy is a state function, we can take any amount of paths to get to the final value. Because we have water going from a liquid to a gas, we have to take into account the phase change, so we need to add the equations of the liquid reaching the boiling point and its vaporization. From the gas phase, we can just cool the gas down, add all the equation values together, and get the answer.