Ice melts according to the process H O(s) → H O(l)

CHEMISTRY · Multi-part · A Level · Chemistry · Thermodynamics · Thermodynamics

Problem

Ice melts according to the process H2_2O(s) → H2_2O(l). For this phase change ΔH=+6.02 kJ mol−1\Delta H = +6.02\,\text{kJ\,mol}^{-1} and ΔS=+22.0 J mol−1 K−1\Delta S = +22.0\,\text{J\,mol}^{-1}\,\text{K}^{-1}, assumed constant with temperature. (a) Calculate ΔG\Delta G for melting ice at 263 K263\,\text{K} (−10 ∘^{\circ}C). Show your work and include units. (b) Calculate ΔG\Delta G for the melting process at 298 K298\,\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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