Thermodynamics

• Thermodynamics


  The study of the relations between heat, work, temperature, and energy

  
• Laws of Thermodynamics

  • Describe how the energy in a system change and whether the system can perform useful work on its surroundings
• 0th Law


  1. If two objects are in equilibrium with another object, therefore, they are also in equilibrium with each other

  2. Thermal Equilibrium = No heat transfer

  3. Heat moves from hot to cold surface

  
• 1st Law


  Law of Conservation of Energy. Energy can't be created nor destroyed. It can, however, be transferred and transform into another form
• 2nd Law


  • The entropy of the universe is always increasing
  • Entropy (∆S) is the tendency of a matter to become disorganized
  • Everything is doomed for chaos and destruction
  • Your room will have a chance of becoming disorganized as time goes by, but never a chance of it becoming more organized on its own
• 3rd Law


  • The entropy of a crystalline solid at a temperature of zero Kelvin (absolute zero) is equal to zero
  • Solid has lesser entropy than liquid and gas since its particles are more organized
• System


  The collection of bodies, matter, or mass that is being studied
• Surrounding


  What's left in the universe, except the system
• Enthalpy (∆H)


  The total internal energy (∆U) of a system
• Types of Systems


  • Isovolumetric: ∆U = Q, Any change in energy is the result of heat transfer, Constant volume, W = 0
  • Isothermal: Q = W, Heat transferred us completely used for work, Constant temperature, ∆U = 0
  • Adiabatic: ∆U = - W, Internal energy is used exclusively for work, No heat transfer, Q = 0
  • Isolated System: ∆U = 0, No change in internal energy, Q = 0, W = 0

  
• Gibbs Free Energy (∆G)


  ∆G = ∆H - T∆S, Tells us about the spontaneity of a process
• Gibbs Free Energy Relationships

  • Spontaneous: ∆G = -, Thermodynamically favorable, Always spontaneous, Never nonspontaneous
  • Nonspontaneous: ∆G = +, Thermodynamically unfavorable, Always nonspontaneous, Never spontaneous
  • ∆G = -, ∆H = -, ∆S = +, Energetically favorable, Entropically favorable, Spontaneous
  • ∆G = +, ∆H = +, ∆S = -, Energetically unfavorable, Entropically unfavorable, Nonspontaneous
  • ∆G = +/-, ∆H = +, ∆S = +, Energetically unfavorable, Entropically favorable, Spontaneous at high temperature
  • ∆G = +/-, ∆H = -, ∆S = -, Energetically favorable, Entropically unfavorable, Spontaneous at low temperature
• Thermodynamic systems can be classified as open (exchange matter with surroundings), closed (no exchange of matter but exchange heat/energy), or isolated (neither exchanges matter nor energy).