ACS Domain 5: Energetics (thermochemistry of thermodynamics) Welcome to your ACS Domain 5: Energetics (thermochemistry of thermodynamics) 1. ACS: Energetics (thermochemistry of thermodynamics) Which expression correctly describes the change in entropy (\(\Delta S\)) of a reaction that forms a complex molecule from simpler molecules? \(\Delta S > 0\) \(\Delta S < 0\) \(\Delta S = 0\) \(\Delta S\) is indeterminate None 2. ACS: Energetics (thermochemistry of thermodynamics) Which condition is not necessary for a reaction to be considered spontaneous under standard conditions? Negative \(\Delta G\) (Gibbs free energy) Positive \(\Delta S\) (Entropy) Temperature independent Negative \(\Delta H\) (Enthalpy) None 3. ACS: Energetics (thermochemistry of thermodynamics) What is the enthalpy change (\(\Delta H\)) for a reaction that is exothermic and results in the formation of gases from solids? \(\Delta H > 0\) \(\Delta H < 0\) \(\Delta H = 0\) \(\Delta H\) depends on pressure None 4. ACS: Energetics (thermochemistry of thermodynamics) Which statement about endothermic reactions is correct? They occur spontaneously at all temperatures. They absorb heat, resulting in a positive \(\Delta H\). They decrease the entropy of the surroundings. They always result in a positive \(\Delta G\). None 5. ACS: Energetics (thermochemistry of thermodynamics) What is the sign of \(\Delta G\) for a reaction where \(\Delta H = -150 kJ\) and \(\Delta S = -100 J/K\) at 298 K? Positive Negative Zero Depends on the system size None 6. ACS: Energetics (thermochemistry of thermodynamics) If a reaction's entropy change (\(\Delta S\)) is negative and its enthalpy change (\(\Delta H\)) is positive, under what conditions might the reaction be spontaneous? High temperature Low temperature At any temperature Never spontaneous None 7. ACS: Energetics (thermochemistry of thermodynamics) For a process that absorbs 40 kJ of heat and does 15 kJ of work on the surroundings, what is the change in internal energy of the system? +25 kJ -25 kJ +55 kJ -55 kJ None 8. ACS: Energetics (thermochemistry of thermodynamics) Which condition is not necessary for a reaction to be considered spontaneous under standard conditions? Negative \(\Delta G\) (Gibbs free energy) Positive \(\Delta S\) (Entropy) Temperature independent Negative \(\Delta H\) (Enthalpy) None 9. ACS: Energetics (thermochemistry of thermodynamics) Which statement about endothermic reactions is correct? They occur spontaneously at all temperatures. They absorb heat, resulting in a positive \(\Delta H\). They decrease the entropy of the surroundings. They always result in a positive \(\Delta G\). None 10. ACS: Energetics (thermochemistry of thermodynamics) If a reaction's entropy change (\(\Delta S\)) is negative and its enthalpy change (\(\Delta H\)) is positive, under what conditions might the reaction be spontaneous? High temperature Low temperature At any temperature Never spontaneous None 1 out of 10 Time is Up! Time's up
