for the evaporation of liquid water predict wheter the entropy change would be positive, negative or zero.?

Question

for the evaporation of liquid water predict wheter the entropy change would be positive, negative or zero. (must write the equation for the process)

Answer 1

H2O(l) --> H2O(g) delta H is positive (endothermic process)

delta S = delta H / T, where delta H is the enthalpy change

Because heating is an endothermic process, enthalpy increases from the reference frame of the system, which is the water. And of course the temperature is in kelvin, so T will always be positive and thus the entropy change is positive. That's the mathematical approach.

From a more conceptual standpoint, entropy is a measure of disorder (the more possible positions that particles can occupy, the more entropy exists. Think of a container being filled with imaginary grid lines, with each square being a possible location of a particle). A liquid is slightly more confined than a gas in that it has a fixed volume and can't float freely though the air. It will thus have a lower entropy than gas, which is composed of particles that can potentially occupy any position in a given container due to their ability to float around independently. Entropy increases for every phase transition: solids have the lowest entropy and gases have the highest entropy.

Answer 2

H2O(l) ----> H2O(g)

The entropy change is positive because the system has become more disordered by a liquid becoming a gas.