1. Consider the reaction N₂(g) + 3 H₂(g) → 2 NH₃(g), and the following thermodynamic data: standard heat of formation of NH₃(g), ∆_fH^o = -46.11 kJ/mol; standard molar entropy of N₂(g), SS_m^o = 191.61 J/K-mol; standard molar entropy of H₂(g), S_m^o = 130.684 J/K-mol; and standard molar entropy of NH₃(g), S_m^o = 192.45 J/K-mol. Calculate the ∆H, ∆S, and ∆G for this reaction carried out under standard pressure and temperature conditions. Which of the following are the correct values for ∆H, ∆S, and ∆G?

2. Suppose 2 moles of water at 333 K are added to 4 moles of water at 293 K. What would be the entropy change associated with this process, assuming that there is no exchange of heat with the surroundings? (The heat capacity of water is C_p,m = 75.3 J/K-mol and may be considered to be independent of temperature.)

3. The standard heat of combustion of solid glucose (C₆H₁₂O₆) at 298 K is ∆_cH⁰(298 K) = -2801 kJ/mol. What is the value of ∆_cU⁰(298 K) for glucose (where ∆_cU⁰ denotes the change in internal energy accompanying the combustion of glucose at 1 bar pressure)?

4. Suppose you want to cool a sample of N₂(g) from 25^oC to -195^oC by a one-step process involving a Joule-Thomson expansion in which the final pressure is 1 bar. The Joule-Thomson coefficient for N₂(g) over the specified temperature range may be taken to be μ_J-T = 0.75 K/bar. Calculate the enthalpy change (∆H) associated with this cooling process and determine what the initial pressure (P_initial) of the gas must be in order to realize the desired temperature change. Which of the following equations gives correct results for P_initial and ∆H?

5. When 6.29 g of a certain nonvolatile solute is dissolved in 500 g of water, the freezing point of the resultant aqueous solution is 0.646^oC lower than that of pure water. The cryoscopic constant for water is K_f = 1.856 K-kg/mol. Given this information, what is the molar mass of the solute species?

6. Among the following processes, which would have a ∆G_m value > 0?

7. Consider the reaction 2 C(s) + Cl₂(g) + 2 F₂(g) → CF₂ClCF₂Cl(g), for which the standard reaction enthalpy has a value of ∆_rH⁰ = -890.4 kJ/mol at a temperature of 298 K. What is the value of ∆_rU⁰ for this reaction at T = 298 K?

8. Suppose you wanted to shift the equilibrium position of the reaction 2 NO₂(g) → N₂O₄(g) in the direction that favors more dimer formation. Which of the following changes in reaction conditions would help achieve that goal?

9. Which of the following will have the highest boiling-point temperature?

10. Consider the reaction C₆H₅COOH(s) + (15/2) O₂(g) → 7 CO₂(g) + 3 H₂O(l), for which the standard reaction enthalpy is ∆_rH^o = -3228.2 kJ. Calculate the ∆_rU^o for this reaction and determine whether any thermodynamic work would be done on (w > 0) or by (w < 0) the reaction system if the reaction is carried out at a constant pressure. (Assume that the gases in this reaction exhibit ideal-gas behavior at T = 298.15 K and P = 1 bar.)

11. Consider a gas for which the equation of state P(V_m – b) = RT (with b = 0.04 dm³/mol) can be used to describe its P-V-T behavior. Suppose a 2-mol sample of this gas is compressed isothermally and reversibly from an initial volume of 10 dm³ to a final volume of 1 dm³. How much work (w) is done on the gas sample in this compression process, and how much is the internal energy (U) of the gas changed?

12. Consider the following reaction for the decomposition of sodium bicarbonate:

2 NaHCO₃(s) → Na₂CO₃(s) + CO₂(g) + H₂O(l)

The ∆_rH⁰ and ∆_rS⁰ for this reaction have values of 85.2 kJ/mol and 215 J/K-mol, respectively. What is the minimum temperature required for an NaHCO₃(s) sample to spontaneously decompose into the products shown above (under 1 bar pressure conditions)?

13. A 1.50-mol sample of an ideal gas at 245 K and 0.75 bar pressure is altered by some process that takes it to a state in which its temperature is increased to 295 K and its pressure is increased to 0.90 bar. What will be the enthalpy change (∆H) of the gas in this process?

14. If you have 1.55 mol of F₂(g) at 1.11 atm pressure and a temperature of 0^oC, what is the volume of this gas sample, assuming ideal-gas behavior?

15. The equilibrium constant for the reaction H₂(g) + ½O₂(g) ↔ H₂O(l) is reported to have a value of 3.5 x 10⁴¹ at a temperature of 298 K. Given this information, what is the value of ∆_rG⁰ for this reaction at 298 K?

16. Consider a real gas which, at a temperature of 298 K and some particular pressure P, has a fugacity coefficient with a value of 1.75. At the given pressure P, what is the difference between the chemical potential of the real gas versus that of an ideal gas? That is, what is the value of μ(real gas) – μ(ideal gas)?

17. Consider a process in which exactly 107 J of heat is added to 1 mol of CH₃OH(g) under constant-volume conditions. If the initial temperature of the methanol vapor sample is 298 K, what will be the temperature of the vapor after the 107 J of heat is added? You may assume ideal-gas behavior and use a value of 43.89 J/K-mol for C_p,m (the molar heat capacity of methanol vapor under constant-pressure conditions).

18. The equilibrium constant (K_c) for the hydrolysis of adenosine triphosphate (ATP) to adenosine diphosphate (ADP) and phosphate is 1.67 x 10⁵ mol/dm³ at 37^oC, and the ∆_rH⁰ for this reaction has a value of -20.1 kJ/mol. Given this information, what is the value of ∆_rS⁰ for the reaction?

19. Methanol boils at a temperature of 337.2 K under standard pressure (P = 1 bar) conditions, and its standard enthalpy of vaporization is ∆_vapH⁰ = 35.27 kJ/mol. What is the standard entropy of vaporization of methanol?

20. Consider a heat engine that operates on a Carnot cycle and uses an ideal gas as a working fluid. Suppose that the heat reservoir of the engine supplies 1 kJ of heat to the system during an isothermal expansion process at a temperature of 900 K, and the system subsequently gives up heat to heat sink during an isothermal compression process at a temperature of 300 K. What would be the maximum efficiency (η_max) achievable with this engine, and what would be the maximum net work (w_net,max) that one could derive from this engine?

21. Consider the phase transformation process C(graphite) → C(diamond). The ∆G for this process at 1 bar pressure and a temperature of 298 K has a value of 2.900 kJ/mol, and the ∆S for the process under these same pressure and temperature conditions has a value of -3.36 J/K-mol. If you raised the temperature from 298 K to 1000 K, but kept the pressure constant at 1 bar, would this increase, decrease, or not change the thermodynamic stability of graphite versus diamond?

22. The heat capacity of a substance can be measured under either constant-volume or constant-pressure conditions. Which of the following sets of relationships between C_v (heat capacity under constant-volume conditions) and C_p (heat capacity under constant-pressure conditions) are always true?

23. What is the equilibrium pressure of NH₃(g) over a sample of NH₄Cl(s) as a result of decomposition at 25h^oC, given that ∆_rG⁰ = 91.12 kJ for the reaction NH₄Cl(s) ↔ NH₃(g) + HCl(g)?

24. The vapor pressure of pure liquid toluene at 300 K is P* = 3.572 kPa, and the vapor pressure of pure liquid benzene at 300 K is P* = 9.657 kPa. Assuming that mixtures of toluene and benzene behave as ideal solutions, what will be the total vapor pressure (P_T) of a toluene-benzene mixture containing 0.60 mole-fraction of toluene at a temperature of 300 K, and what will be the mole-fraction of toluene (X_toluene) in the vapor over this mixture?

25. The molar enthalpy of sublimation of CO₂(s) is 25.23 kJ/mol at the standard sublimation temperature, 194.6 K. What is the molar entropy of sublimation of CO₂(s) at the standard sublimation temperature?