At fixed T and pressure, a closed system with only pressure-volume work has negative delta G for a proposed change. What does this mean?

• The forward change is thermodynamically favored
• The forward change requires an external drive
• The forward change must happen instantaneously

Gibbs free energy G combines enthalpy H and entropy S at temperature T. How?

• H plus TS
• H over T
• H-TS

A spontaneous process always happens fast.

At fixed T and pressure, the reaction Gibbs energy is zero at the system's current composition. What does this indicate?

• A maximum possible reaction speed
• An externally forced reaction direction
• No net thermodynamic reaction drive

Pure ice at atmospheric pressure does not melt spontaneously below its melting temperature but does above it. Which relation explains melting above that boundary?

• The positive delta H term exceeds T delta S for melting
• The positive T delta S term exceeds delta H for melting
• The melting entropy change becomes negative when warmed

In a stated model with constant delta H<0 and delta S>0, when is delta G=delta H-T delta S negative?

• At every positive T in this model
• Only at low positive T in this model
• Only at high positive T in this model

Under the Gibbs spontaneity conditions, an endothermic change has negative delta G. Which relation must hold?

• The negative entropy change outweighs absorbed heat
• The enthalpy change equals zero despite heat absorption
• The positive T delta S term exceeds positive delta H

Treat delta H=60 J/mol and delta S=0.2 J/(mol K) as constant over the relevant range. At what temperature does delta G=delta H-T delta S become zero?

• 12 K
• 300 K
• 0.003 K