Physical chemistry is a branch of chemistry that deals with the study of the physical properties of matter and their relation to chemical reactions. It is a vast field and requires a thorough understanding of various concepts, theories, and formulas. Here is a formula sheet for physical chemistry that will help you to understand the subject better.

**The Gas Laws**
- Boyle's Law: P1V1=P2V2
- Charles's Law: V1/T1=V2/T2
- Gay-Lussac's Law: P1/T1=P2/T2
- Combined Gas Law: (P1V1)/T1=(P2V2)/T2
- Ideal Gas Law: PV=nRT

**Thermodynamics**
- First Law of Thermodynamics: ΔU = Q - W
- Enthalpy Change: ΔH = ΔU + PΔV
- Second Law of Thermodynamics: ΔS = Q/T
- Gibbs Free Energy: ΔG = ΔH - TΔS
- Entropy Change: ΔS = nR ln(V2/V1) + nCp ln(T2/T1)

**Chemical Equilibrium**
- Equilibrium Constant: Kc=[Products]/[Reactants]
- Equilibrium Constant for Gases: Kp=Kc(RT)Δn
- Le Chatelier's Principle: When a system at equilibrium is subjected to a stress, the equilibrium shifts in a direction that tends to relieve the stress.

**Acids and Bases**
- pH: pH = -log[H+]
- pOH: pOH = -log[OH-]
- Kw: Kw=[H+][OH-]=1.0 x 10^-14
- Acid Dissociation Constant: Ka=[H+][A-]/[HA]
- Base Dissociation Constant: Kb=[BH+][OH-]/[B]

**Electrochemistry**
- Faraday's Constant: F = 96,485 C/mol
- Nernst Equation: Ecell = E°cell - (RT/nF)ln(Q)
- Standard Reduction Potential: E°cell = E°reduction + E°oxidation
- Gibbs Free Energy and Cell Potential: ΔG = -nFEcell

In conclusion, this formula sheet is a useful guide for students of physical chemistry. It summarizes the key formulas and concepts that are essential for understanding the subject. By mastering these formulas, students can solve complex problems and excel in their exams.