Key Equations and Concepts

Ideal Gas Law:

• PV=nRTPV = nRTPV=nRT
  • PPP: Pressure
  • VVV: Volume
  • nnn: Number of moles
  • RRR: Universal gas constant
  • TTT: Temperature

Internal Energy (U):

• For an ideal gas: U=32nRTU = \frac{3}{2} nRTU=23​nRT (in terms of translational degrees of freedom)

Enthalpy (H):

• H=U+PVH = U + PVH=U+PV
• Useful in processes occurring at constant pressure.

Entropy (S):

• Change in entropy during a process: ΔS=QrevT\Delta S = \frac{Q_{\text{rev}}}{T}ΔS=TQrev​​

Gibbs Free Energy (G):

• G=H−TSG = H – TSG=H−TS
• Determines the spontaneity of a process (negative ΔG\Delta GΔG indicates a spontaneous process).