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16.4 Exercise 31

Avg difficulty 2.5

The evaporation of one mole of water at 298 K has a standard free energy change of 8.58 kJ.
H2O(l)⇌H2O(g)ΔG°=8.58 kJ\text{H}_{2} \text{O} \left(l\right) \rightleftharpoons \text{H}_{2} \text{O} \left(g\right) \Delta G ° = \text{8}.\text{58 kJ}

(a) Is the evaporation of water under standard thermodynamic conditions spontaneous?

(b) Determine the equilibrium constant, KP, for this physical process.

(c) By calculating ∆G, determine if the evaporation of water at 298 K is spontaneous when the partial pressure of water, PH2O,P_{\text{H}_{2} \text{O}} , is 0.011 atm.

(d) If the evaporation of water were always nonspontaneous at room temperature, wet laundry would never dry when placed outside. In order for laundry to dry, what must be the value of PH2OP_{\text{H}_{2} \text{O}} in the air?

OpenStax Chemistry 2e, 16.4 Free Energy, exercise 31

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Adapted from General Chemistry © 2019 Rice University. Licensed under CC BY 4.0. Sources: Chemistry 2e, Chemistry: Atoms First 2e. Imported at revision 32c7196.