Problem 1: At boiling point T_b of a liquid, the vapor pressure of the liquid equals surrounding pressure P. Which of the following statements is true?
Answers:

• Water is good propellant for asthma inhaler
• T_b = ΔS / ΔH
• T_b at higher altitudes is lower

Problem 2: The entropy (S) of a system is linearly proportional to the following variable or expression:
Answers:

• the logarithm of the total number of possible states
• its enthalpy
• the total number of possible states
• the absolute temperature
• the absolute temperature multiplied by the logarithm of the total number of states
• the gas volume

Problem 3: Standard enthalpy and standard entropy of formation of liquid methanol at 25°C are -238.4 kJ/mol and -241.6 J/(mol K), respectively. Estimate the standard free energy of formation of liquid methanol at this temperature.
Answers:

• -37.15 J/mol
• impossible to tell
• 71.758 kJ/mol
• 114.1 J/mol
• -166.4 kJ/mol

Problem 4: Choose the most accurate statement about protein-drug binding reaction:
Answers:

• it can be either endo- or exothermic
• its free energy depends on the square of the drug concentration
• it is always endothermic
• it is always exothermic
• it always leads to a lower entropy state

Problem 5: Molar entropy and enthalpy of 1:1 Pravastatin binding to its target protein, HMG-CoA reductase, at 25°C are equal to 24.16 cal/(K mol) and -2.5 kcal/mol, respectively. Determine the Gibbs free energy change when 1 mmol of reductase/Pravastatin complex is formed from 1 mmol protein and 1 mmol drug.
Answers:

• -7.2 cal
• 7.2 cal
• -4.7 cal
• -9.7 cal
• 4.7 cal
• 9.7 cal

Problem 6: At its boiling temperature and atmospheric pressure, the vaporization enthalpy of Desflurane (an inhalational anesthetic) is 39 cal/g (note the units: calories not joules, and grams not moles). Its molar vaporization entropy is ~ 92.76 J/(mol K). Which of the following numbers is closer to the boiling temperature of Desflurane? MW(Desflurane) = 168 g/mol. Use the transition equation that relates ΔH_transition and Delta;S_transition
Answers:

• 373 K
• 295 °C
• 22.5 °C
• 43 °C
• 29.5 K

Problem 7: Gibbs free energy (G), enthalpy (H) and entropy (S) are related as follows (T is temperature, and R is gas constant):
Answers:

• G = H - RS
• G = H/T + S
• G = H - RS
• G = H + S lnT
• G = H - TS

Problem 8: Which of the statements about the Gibbs free energy or its components is correct?
Answers:

• the entropy of a state determines the direction of the spontaneous process
• the higher entropy lowers the Gibbs free energy and makes it more favorable
• the entropy of one state is always the enthalpy of this state divided by the current temperature
• the entropic part of the Gibbs free energy is independent from temperature
• the higher entropy increases the Gibbs free energy

Problem 9: The standard enthalpy of crystallization of a drug in solution at 290K is -50 kJ/mol. Will the drug spontaneously precipitate at this temperature?
Answers:

• the drug will not form crystals because the enthalpy change is negative
• the result is unknown because enthalpy alone does not determine the direction of processes
• the enthalpy is too close to the thermal energy and it will stay in solution
• the drug will form crystals and precipitate

Problem 10: Lopinavir binding to HIV protease at 25°C is characterized by 1:1 stoichiometry, molar ΔG of -15.1 kcal/mol and molar ΔH of -3.8 kcal/mol. How does the molar entropy change in the binding reaction?
Answers:

• increases by 37.9 cal/(K mol)
• decreases by 0.45 kcal/(K mol)
• does not change
• increases by 11.3 kcal/(K mol)
• decreases by 11.3 kcal/(K mol)
• decreases by 37.9 cal/(K mol)
• increases by 0.45 kcal/(K mol)

Problem 11: On a cold winter day, the temperature outside is -20 °C. The boiling temperature of Heptafluoropropane, a commonly used asthma inhaler propellant, is 255.7 K. Student Y had to walk to her class for 30 minutes carrying her Heptafluoropropane-based inhaler in her purse. She experienced an asthma attack before entering the class. Which of the following most likely happened when she tried to use the inhaler?
Answers:

• The inhaler dispensed the usual dose of medication
• The inhaler dispensed twice the usual dose of medication in a single puff
• The contents of the inhaler froze (became solid)
• The inhaler exploded
• The inhaler did not dispense the medication, or dispensed a lower dose

Problem 12: Calorimetric data on binding of several anti-HIV drugs to their common target, HIV protease, is given in the table (all values in kcal/mol reasured at 25°C). Which drug has the highest binding affinity constant (strongest binding)?
Answers:

• Saquinavir
• Ritonavir
• Darunavir
• Amprenavir
• Lopinavir
• Nelfinavir
• Atazanavir
• Tipranavir
• Indinavir