Thermodynamics

• thermodynamics
• chemical thermodynamics
• thermochemistry

Laws of thermodynamics

• zeroth law of thermodynamics

• first law of thermodynamics

  • $\Delta U=Q-W$ is the change in internal energy of the system, where:
    • $Q$ is the heat added to the system
    • $W$ is the work done by the system
  • (or equivalently $\Delta U=Q+W$, where $W$ is the work done on the system)

• second law of thermodynamics

• third law of thermodynamics

• state function (פונקציית מצב)

  • examples: internal energy ($U$), enthalpy ($H$), entropy ($S$), pressure ($P$), and temperature ($T$)
  • (The differential $dX$ (of a state function) is an exact differential)
    • exact differential describes a change in a state function
    • $\oint dX=0$

• path function (or process function)

  • examples: $Q$ and $W$
  • inexact differential (a differential whose integral depends on the path taken between two points)
    • (e.g. $\delta W$ and $\delta Q$)

• equation of state

  • e.g., ideal gas law

• thermal energy (אנרגייה תרמית)

  • by Wikipedia it can refer to:
    • internal energy
    • heat
    • the characteristic energy

• thermodynamic work

  • todo https://physics.stackexchange.com/questions/598304/what-does-work-in-thermodynamics-mean-versus-in-other-parts-of-physics
  • pressure-volume work
    • $\delta W=PdV$
    • $W=\int PdV$
  • $W=\int VIdt$

Thermodynamic system

(source: commons.wikimedia.org)

• thermodynamic system (or system)

  • closed system
  • open system
  • isolated system

• surroundings

• thermodynamic processes

  • isobaric (אִיזוֹבָּרִי, אחיד-לחץ, קבוע-לחץ)
  • isochoric (אִיזוֹכוֹרִי, אחיד-נפח, קבוע-נפח)
  • isothermal (איזותרמי, אחיד-טמפרטורה, קבוע-טמפרטורה)
  • adiabatic (אַדְיַאבָּטִי)
  • isentropic (אִיזֶנְטְרוֹפִּי, אחיד-אנטרופיה, קבוע-אנטרופיה)
  • isenthalpic (אִיזֶנְתַּלְפִּי, אחיד-אנתלפייה, קבוע-אנתלפייה)
  • quasistatic
  • polytropic
  • free expansion
    • Joule expansion
  • reversible (הפיך)
  • irreversible (לא-הפיך)
  • endoreversibility

• exothermic process

  • exothermic reaction
    • ”A reaction for which the overall standard enthalpy change $\Delta H^{\text{unicode}x26ac}$ is negative” (IUPAC)

• endothermic process

  • endothermic reaction

• spontaneous process

  • (thermodynamically favorable)

• nonspontaneous process

  • (thermodynamically unfavorable)

• pressure–volume diagram (or PV diagram)

Chemical energy

• chemical energy

• ”the energy of chemical substances that is released when the substances undergo a chemical reaction and transform into other substances”

• breaking bonds requires energy (endothermic)

• forming bonds releases energy (exothermic)

Heat

• heat ($Q$)
  • “the form of energy crossing the boundary of a thermodynamic system by virtue of a temperature difference across the boundary” (Wikipedia)
  • $Q=mc\Delta T=C\Delta T$
  • SI unit: $\mathrm{J}$

Heat capacity

• heat capacity (or thermal capacity) $C$ (קיבול חום)
  • SI unit: $\mathrm{J}\cdot {\mathrm{K}}^{-1}$
• molar heat capacity $c_m=\frac{C}{n}$ (קיבול חום מולי)
  • SI unit: $\mathrm{J}\cdot {\mathrm{K}}^{-1}\cdot \mathrm{mo}{\mathrm{l}}^{-1}$
• specific heat capacity ($c$) (קיבול חום סגולי) is the amount of heat required to raise the temperature of one unit of mass (typically $1\mathrm{kg}$ or $1\mathrm{g}$) of a substance by $1^{\circ }\mathrm{C}$ (or equivalently $1^{\circ }\mathrm{K}$)
  • aka: massic heat capacity or specific heat (חום סגולי)
  • SI unit: $\mathrm{J}\cdot \mathrm{k}{\mathrm{g}}^{-1}\cdot {\mathrm{K}}^{-1}$

Heat transfer

• heat transfer

  • thermal conduction
    • thermal conductivity $\kappa$
    • thermal resistivity $\rho$
  • convection (הסעה)
  • thermal radiation (קרינה תרמית)
    • “electromagnetic radiation emitted by the thermal motion of particles in matter” (Wikipedia)

• thermal equilibrium

• calorimetry (קלורימטריה)

Latent heat

• latent heat (or latent energy, heat of transformation) (חום כמוס)
  • $Q=mL$
    • $L$ is the specific latent heat of the substance
• enthalpy of fusion (or latent heat of fusion)
• enthalpy of sublimation (or latent heat of sublimation)
• enthalpy of vaporization (or latent heat of vaporization)

Heating value

• heating value (ערך-היסק) 
  • (or energy value, calorific value (ערך קלורי), heat of combustion (חום-בערה))
  • “the amount of heat released during the combustion of a specified amount of it” (Wikipedia)
  • the “amount” of fuel may be either: amount of substance, mass or volume, and the quantities and units are:
    • energy/mole:
    • energy/mass: $J/kg$, $Cal/kg$
    • energy/volume:
  • fuel value
    • ”The energy released when 1 g of any substance is combusted” (Brown, 2012)
    • “the amount of energy per g of food” (Denniston, 2022)
  • higher heating value (HHV)
  • lower heating value (LHV)
• specific energy (or massic energy, gravimetric energy density)

Potentials

• thermodynamic potential (or thermodynamic potential energy)

  • Gibbs free energy (or Gibbs energy)
    • $G=U+PV-TS$
    • $\Delta G=\Delta H-T\Delta S$
    • $\Delta G<0$ → spontaneous
    • $\Delta G=0$ → equilibrium
    • $\Delta G>0$ → nonspontaneous
  • enthalpy
  • internal energy
  • Helmholtz free energy ($A$)
  • grand potential (or Landau potential) ($\Omega$)

• (thermodynamic) free energy

Enthalpy

• enthalpy (אֶנְתַּלְפִּיָּה)

  • $H=U+PV$
  • $\Delta H=H_{\text{products}}-H_{\text{reactants}}$
  • A reaction is endothermic if $\Delta H>0$, and exothermic if $\Delta H<0$

• The standard enthalpy of reaction ($\Delta H_{\text{rxn}}^{\circ }$)

• The standard enthalpy of formation (or standard heat of formation) ($\Delta H_f^{\circ }$)

• Hess’s law of constant heat summation (or Hess’s law)

• specific enthalpy

  • $h=H/m$
  • SI unit: $J/kg$

• molar enthalpy

  • $H_m=H/n$
  • SI unit: $J/mol$

Bond energy

• bond dissociation energy (BDE)
• bond energy (BE) (or mean bond, bond enthalpy, average bond enthalpy, or bond strength) (אנרגיית קשר)

Internal energy

• **** ($U$) (אנרגיה פנימית)

• in contrast to:

  • macroscopic kinetic energy
  • macroscopic potential energy
    • elastic
    • gravitational

• for an ideal gas: $\Delta U=n{C}_{V,m}\Delta T$

  • $n$ is the number of moles
  • $C_{V,m}$ is molar heat capacity at constant volume
  • $\Delta T$ is the change in temperature

• todo

  • $\Delta U={\sum }_i{p}_i{E}_i$
  • $\Delta U=\sum _i{E}_i$
  • $U=U_{\text{micro,pot}}+U_{\text{micro,kin}}$

Entropy

• entropy ($S$)

Temperature

• temperature

  • thermodynamic temperature (or absolute temperature) (טמפרטורה מוחלטת)
  • absolute zero
  • Celsius
    • degree Celsius (${}^{\circ }\mathrm{C}$)
    • (sometimes ${\mathrm{C}}^{\circ }$ is used for temperature interval)
  • $\overline{\text{KE}}=\frac{3}{2}{k}_{B}T$

• thermal expansion (התפשטות תרמית)

  • $\Delta L=\alpha L_0\Delta T$
  • $\Delta V=\beta V_0\Delta T$

(source: commons.wikimedia.org)

• phase diagram
  • lines of equilibrium (or phase boundaries)
  • The critical point (specifically liquid–vapor critical point) is the point $(T_c,P_c)$ in which the liquid–gas equilibrium curve ends. Beyond this point, the distinction between liquid and gas vanishes, and the substance becomes a supercritical fluid.
    • $T_c$ is the critical temperature
    • $P_c$ is the critical pressure
  • The triple point is the point $(T_{tp},P_{tp})$ in which all three phases coexist in dynamic equilibrium

misc.

• critical point (or critical state)
  • (e.g., the liquid–vapor critical point)

References

• Brown, Theodore L. (2012). Chemistry. Prentice Hall.
• Denniston (2022). General, Organic, and Biochemistry. McGraw-Hill Education.