Chemistry

Problem

Ice melts according to the process H

_2

O(s) → H

_2

O(l). For this phase change

\Delta H = +6.02\,\text{kJ\,mol}^{-1}

and

\Delta S = +22.0\,\text{J\,mol}^{-1}\,\text{K}^{-1}

, assumed constant with temperature. (a) Calculate

\Delta G

for melting ice at

263\,\text{K}

(−10

^{\circ}

C). Show your work and include units. (b) Calculate

\Delta G

for the melting process at

298\,\text{K}

(25

^{\circ}

C). (c) Using your numerical results from parts (a) and (b), explain why ice is stable in a household freezer at −10

^{\circ}

C but not on a kitchen countertop at room temperature. (d) Determine the temperature at which solid and liquid water are in equilibrium under 1 bar pressure based on the provided thermodynamic data. Compare your calculated value with the commonly accepted melting point of ice and comment on any discrepancy.

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