Thermodynamics in Dry ice

Chemistry Level 2

Dry ice, sometimes referred to as "cardice" or as "card ice" (chiefly British English), is the solid form of carbon dioxide. It is used primarily as a cooling agent. Its advantages include lower temperature than that of water ice and not leaving any residue (other than incidental frost from moisture in the atmosphere). Dry ice sublimates at $$−78.5$$ °C ($$−109.3$$ °F) at Earth atmospheric pressures. Which of the following statements is correct about the sublimation of dry ice? ($$\Delta H$$, $$\Delta S$$ and $$\Delta G$$ mean the change in enthalpy, entropy and Gibbs free energy, respectively.)

a) $$\Delta H > 0$$ and $$\Delta S > 0$$, and $$\Delta G < 0$$ for all temperatures.

b) $$\Delta H > 0$$ and $$\Delta S < 0$$, and $$\Delta G > 0$$ for all temperatures.

c) $$\Delta H < 0$$ and $$\Delta S > 0$$, and $$\Delta G < 0$$ for all temperatures.

d) $$\Delta H > 0$$ and $$\Delta S > 0$$, and $$\Delta G < 0$$ for high temperatures.

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