Question 4. For the carbon dioxide sublimation, CO2(s) → CO2(g), the system is the solid and gaseous carbon dioxide, the sublimation temperature is 195 K, and the enthalpy change of sublimation is 26.1 kJ/mol.
a. Circle what must be true at all temperatures. If nothing, circle none.
ΔSsys < 0 ΔSsys = 0 ΔSsys > 0 ΔSsur < 0 ΔSsur = 0 ΔSsur > 0 ΔStot < 0 ΔStot = 0 ΔStot > 0
b. Circle what is true about the total entropy change for the sublimation of CO2 at 298 K.
ΔStot < 0 ΔStot = 0 ΔStot > 0
c. Circle what is true about the entropy change of the surroundings for the sublimation of CO2 at 195 K.
ΔSsur < 0 ΔSsur = 0 ΔSsur > 0
d. Calculate the vapor pressure in bar of carbon dioxide at its sublimation temperature. Recall that the equilibrium constant for sublimation is Kp = P.