2. Rubidium has a heat of vaporization of 69.0 kJ/mol at its boiling point (686oC). For the process Rb(l)-->Rb(g) at 1 atm and 686oC. Calculate the value of DS.
0 69.0 kJ/mol 71.9 J/K mol 61.0 kJ/mol -7.97 kJ/mol
3. A change of state occurs within a system and produces 64.0 kB of heat which is transferred to the surrounding at a constant pressure and a constant temperature of 300K. For this process DSsurroundings is:
64.0 kJ -64.0 kJ -213 J/K 213 J/K none of these
4. DS for the universe is:
always positive sometimes positive always negative sometimes negative constant
5. Choose the CORRECT statement:
Exothermic reactions are always spontaneous Free energy is independent of temperature. A reaction which exhibits a negative value of D S cannot be spontaneous. At constant P and T, a decrease in free energy insures an increase in the entropy of the system. None of the above statements are true.
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