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Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily
HOME > Lecture catalog / Research summary > Glossary > Thermodynamics
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The study of the effects of work, heat and energy on a system
conserned with large scale observations without the consideration of molecular structure Zeroth law: thermodynamic equilibrium and temperatureFirst law: work, heat, and energy Second low: entropy Symbols for buget changeΔ: finite changeδ: minutely-small change d; instantaneous change Ex. Q: heat quantity (specific heat) → ΔQ, δQ, dQ History of thermodynamics (熱力学史)Boyle, Robert 1627-1691Mariotte, Edme 1620-1684 Becher, Johann Joachim 1635-1682 Huygens, Christiaan 1629-1695, Holland
1678 Huygens principle assistant of Huygens - in Engliand - assisting Boyle's experiments |
[ temperature (climate)] developed steam engine Newcomen, Thomas 1663-1729, Englanddeveloped practical steam engine Lavoisier, Antoine Laurent 1743-1794Stephenson, George 1781-1848, England, engineer contributed to the commercialization of steam locomotives Séguin, Marc 1786-1875, Frande: steam engineClapeyron, Emile 1799-1864, France: thermodynamics |
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= the law of conservation of energy ≡ the total energy of an isolated system is constant Mayer, Julius Robert von 1814-1878, Doctor in Germany one of the scientists who established the first law |
exothermic reaction (発熱反応) ⇔ endothermic reaction (吸熱反応)
Sorts of reaction heatformation heat or heat of formation (生成熱), same as belowcombustion heat (燃焼熱) - exothermic reaction H2 + 1/2·O2 = H2O + 68.3 kcal decomposition heat (分解熱)neutralization heat (中和熱) (dis)solution heat (溶解熱) |
Bond energy (結合エネルギー)Bond energy of C-H: (1661.7 KJ/mol)/4 = 415.4 KJ/mol
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Second law of thermodynamics defined by Clausius (熱力学第2法則) |
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Def. specific heat (比熱), C: the quantity of heat required to raise the temperature of 1 gram of a substance by 1°C (cal or J/g/°C
Water: 1 cal (or 4,186 J)/g/°C Def. Enthalpy (heat content), H ≡ U + PV
a thermodynamic parameter that gauges the total heat present in a thermodynamic system where the pressure is regular Q. The change in enthalpy of a system is equivalent to the heat absorbed by the system at a (A. constant pressure) Q. The change in enthalpy of an exothermic reaction is (A. always negative) Q. If the heat is transmitted to a system at a steady pressure. In that case, the enthalpy of the system will (A. increase) |
Factors affecting enthalpyAmount of reactant and productPhysical state of reactants and products Allotropic modification Temperature and pressure Def. Enthalpy change (of an atom): the amount of heat absorbed or evolved in a reaction carried out at a steady pressure Def. Standard enthalpy of formation (標準生成エンタルピー), ΔfH°: the change in enthalpy when 1 mole of the compound is formed under standard conditions Q. Calculate the enthalpy change: CH4(g) + 2O2(g) → CO2(g) + 2H2O(l),given that enthalpies of formation of CH4, CO2 and H2O are 74.8 kJ/mol, −393.5 kJ/mol, and −286 kJ/mol, respectively. A. Enthalpy change:
ΔH°p – ΔH°r (p: products. r: reactants) |
(Thermodynamic) free energy (自由エネルギー)Helmholtz free energy, F (or A) = U - TSEq. U = -T2·∂/∂T(F/T) Pr. RS = -T2·∂/∂T(F/T) = -T2·((T·∂F/∂T - dT/dT·F)/T2) = F - T·∂F/∂T = F - T·(∂(U - TS)/∂T) = F + TS = LS // |
Gibbs free energy, G ≡ H - TS |
[unit]
Celsius (摂氏)Celsius (temperature) scale, or degree Celsiust (°C) = T (K) - 273.16 (K) |
Fahrenheit (華氏)Fahrenheit (temperature) scale, or degree Fahrenheit°F = 1.8 (= 9/5) × °C + 32 ⇔ °C = (5/9)·(°F - 32)
°F: -40___0___50__100 |
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Def. a measurement of the energy in a system or process that is not available to do work
Cf. the amount of order or lack of order in a system (sociology) 1824 Carnot principle (カルノー原理)Clausius, Rudolf 1850 proposed the term "entropy" (appeared in 1865) = establishment of thermodynamics |
 Fig. Relationships between the parameters of thermodynamics, U, H, F, G, TS and PV. |
Colloid (コロイド) |
