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Thermodynamics (熱力学)

Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily

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 temperature
First law: work, heat, and energy
Second low: entropy
Symbols for buget change
Δ: finite change
δ: minutely-small change
d; instantaneous change

Ex. Q: heat quantity (specific heat) → ΔQ, δQ, dQ

History of thermodynamics (熱力学史)

Boyle, Robert 1627-1691
Mariotte, Edme 1620-1684
Becher, Johann Joachim 1635-1682
Huygens, Christiaan 1629-1695, Holland

1678 Huygens principle
1690 Huygens–Fresnel principle

Papin, Denis (1647-1712?), inventor in Frande

assistant of Huygens - in Engliand - assisting Boyle's experiments

[ temperature (climate)]

Savery, Thomas 1650-1715, England

developed steam engine

Newcomen, Thomas 1663-1729, England

developed practical steam engine

Lavoisier, Antoine Laurent 1743-1794
Stephenson, George 1781-1848, England, engineer

contributed to the commercialization of steam locomotives

Séguin, Marc 1786-1875, Frande: steam engine
Clapeyron, Emile 1799-1864, France: thermodynamics

Heat engine (熱機関)

First law of thermodynamics (熱力学の第1法則)

= 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

Reaction heat or heat of reaction (反応熱)

exothermic reaction (発熱反応) ⇔ endothermic reaction (吸熱反応)
Sorts of reaction heat
formation heat or heat of formation (生成熱), same as below
combustion 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

bond energy

Kinetic theory of matter (物質の分子運動論)

Second law of thermodynamics defined by Clausius (熱力学第2法則)

Enthalpy, H (エンタルピー)

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), HU + PV

a thermodynamic parameter that gauges the total heat present in a thermodynamic system where the pressure is regular
≡ the sum of the internal energy and the product of the pressure and volume of a thermodynamic system

Q. If the activation energy is equal for both forward and backward reactions, then (A. ΔH = 0)
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 enthalpy
Amount of reactant and product
Physical 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)
= (ΔH°CO2 + ΔH°H2O) – (ΔH°CH4 + 2ΔH°O2)
= (-393.5 − 286) – (74.8 + 2 × 0) (kJ/mol) = -890.7 kJ/mol

Energy (エネルギー, E)

(Thermodynamic) free energy (自由エネルギー)

Helmholtz free energy, F (or A) = U - TS
Eq. 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, GH - TS


Temperature (温度)

Celsius (摂氏)
Celsius (temperature) scale, or degree Celsius
t (°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
°C: -40_-17.8__10__37.8

Entropy, S (エントロピー)

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.

Phase, three phases of a substance ()

High-polymer solution (高分子溶液)

Colloid (コロイド)