Laws of Thermodynamics - Thermodynamics and Statistical Mechanics - Lecture Slides, Slides of Thermodynamics

Download Laws of Thermodynamics - Thermodynamics and Statistical Mechanics - Lecture Slides and more Slides Thermodynamics in PDF only on Docsity! Thermodynamics and Statistical Mechanics Review for Quiz 1 Docsity.com Laws of Thermodynamics • First law: đQ – đW = dU • Energy is conserved Docsity.com Second Law Variations •No series of processes is possible whose sole result is the absorption of heat from a thermal reservoir and the complete conversion of this energy to work. •There are no perfect engines! Docsity.com Second Law Variations •No series of processes is possible whose sole result is the transfer of heat from a reservoir at a given temperature to a reservoir at a higher temperature. •There are no perfect refrigerators! Docsity.com Zeroth Law • If two systems are separately in thermal equilibrium with a third system, they are in thermal equilibrium with each other. Docsity.com van der Waals equation of state ( ) RTbv v aP v a bv RTP =−      + − − = 2 2 or , Then, This equation has a critical value of T which suggests a phase change. The next slide shows graphs for several values of T . Docsity.com Thermal Expansion •Expansivity or Coefficient of Volume Expansion, β. TVT T VV PT T v vT V V P PP ∆=∆      ∂ ∂=∆       ∂ ∂=      ∂ ∂= β β β ),( 11 Docsity.com Compressibility • Volume also depends on pressure. • Isothermal Compressibility: PVP P VV PT P V V T T ∆−=∆      ∂ ∂=∆       ∂ ∂−= κ κκ ),( 1 Docsity.com Thermal Efficiency (η) 2 12 2 1 2 1 2 12 2 1 1 T TT T T Q Q Q QQ Q W −=−= −= − == η η If T1 = 0, η = 1 (100%) Docsity.com For a Carnot Engine TQ T T Q Q ∝= 1 2 1 2 1 2 1 2 T T Q Q −= 0 2 2 1 1 =+ T Q T Qor Docsity.com Entropy 0=→ ∫∑ T Qd T Qd i i i dS T Qd = For reversible processes. Entropy is a state variable. Docsity.com Ideal Gas Rcc T PvP T Tvcc Tvcc vp vp vp =− ==− =− 2 2 1 κ β Docsity.com Properties • From first law: TdS = dU + PdV, or • Internal Energy dU = TdS – PdV U(S, V) • Enthalpy: H = U + PV • dH = TdS + VdP H(S, P) Docsity.com New Potentials • Helmholtz Function: • F = U – TS • Gibbs Function: • G = U – TS + PV • G = H – TS • G = F + PV Docsity.com