Answer the following questions related to H2O. Substance ΔG°f at 298K(kJ/mol)
H2O(l) −237.2
H2O(g) −228.4

(a) Using the information in the table above, determine the value of ΔG° at 298K for the process represented by the equation H2O(l)⇄H2O(g).

Question 2
(b) Considering your answer to part (a), indicate whether the process is thermodynamically favorable at 298K. Justify your answer.

Question 3
(c) Considering your answer to part (b), explain why H2O(l) has a measurable equilibrium vapor pressure at 298K.

Question 4
Water vapor can be produced in two different processes, as represented below.

Process 1 Process 2
H2O(s)⇄H2O(g) H2O(l)⇄H2O(g)
(d) In terms of concepts of entropy and the particle-level structure of the different phases of water, explain why the change in entropy, ΔS, is greater for process 1 than for process 2.

1. 8.8kJ/mol

2. The process is not favorable.

3. The reason is in the answer.

4. Process 1.

Explanation:

1. ΔG° = ΔG° products - ΔG° reactants

ΔG° = -228.4kJ/mol - (-237.2kJ/mol) = 8.8kJ/mol

2. The process is not favorable because ΔG > 0

3. As the reaction is an equilibrium, a little amount of water will change from liquid to gas. This is the reason because of water has a measurable equilibrium vapor pressure.

4. Entropy is greater in process 1 because the structure of H2O(s) is more organized than H2O(l) (S of H2O(s) is lower than H2O(l)).

ΔS of H2O(s)⇄H2O(g) is greater than H2O(l)⇄H2O(g)

the correct option is c.

isotopes refers to different forms of the same element with the same atomic number but different mass number as a result of difference in their neutron numbers. isotopes have different relative atomic mass but share the same chemical properties.