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Chemical Thermodynamics I Chemical Reaction Engineering Summer Term 2010 Institute for Process Engineering Chair for Chemical Process Engineering Prof. Dr.-Ing. A. Seidel-Morgenstern 3. Tutorial: Chemical Thermodynamics I Enthalpy, Entropy, Gibbs Free Energy and Equilibrium Constant of a Chemical Reaction The hydrogen-oxygen reaction H2+1/2 O2 )* H2O reaches equilibrium at a total pressure of p = 1:5 bar and a temperature of T = 1000 K. All components behave like ideal gases. Initially, the system consists of a stoichiometric mixture of hydrogen and oxygen. a) What is the enthalpy of reaction for the given system? b) Determine the entropy and Gibbs free energy changes for this reaction. c) Calculate the equilibrium constant Kp. d) Which composition is obtained at equilibrium? Enthalpies and entropies of formation are given in the attached tables (Source: CRC Hand- book of Chemistry and Physics, 85th Edition, CRC Press). The temperature dependence of the reactants’molar heat capacities can be described by means of a second order polynomial: 2 cp;i = Ai + BiT + CiT 1 1 1 2 1 3 Species i Ai / J mol K Bi / J mol K Ci / J mol K 3 6 H2O 31.202 6.1910 10 3.9425 10 4 6 H2 29.068 -4.9696 10 1.5251 10 2 6 O2 25.379 1.3592 10 -4.0258 10 Crystal Liquid Gas ⌬ ⌬ ⌬ ⌬ ⌬ ⌬ fH° fG° S° Cp fH° fG° S° Cp fH° fG° S° Cp Molecular Formula Name kJ/mol kJ/mol J/mol K J/mol K kJ/mol kJ/mol J/mol K J/mol K kJ/mol kJ/mol J/mol K J/mol K HRb Rubidium hydride -52.3 HS Mercapto 142.7 113.3 195.7 32.3 OFCHEMICALSUBSTANCES THERMODYNAMIC PROPERTIES STANDARD HSi Silylidyne 361.0 HTa2 Tantalum hydride -32.6 -69.0 79.1 90.8 H2 Hydrogen 0.0 130.7 28.8 H2KN Potassium amide -128.9 H2KO4P Potassium dihydrogen phosphate -1568.3 -1415.9 134.9 116.6 H2LiN Lithium amide -179.5 H2Mg Magnesium hydride -75.3 -35.9 31.1 35.4 H2MgO2 Magnesium hydroxide -924.5 -833.5 63.2 77.0 H2N Amidogen 184.9 194.6 195.0 33.9 H2NNa Sodium amide -123.8 -64.0 76.9 66.2 H2NRb Rubidium amide -113.0 H2N2O2 Nitramide -89.5 H2NiO2 Nickel(II) hydroxide -529.7 -447.2 88.0 H2OWater -285.8 -237.1 70.0 75.3 -241.8 -228.6 188.8 33.6 H2O2 Hydrogen peroxide -187.8 -120.4 109.6 89.1 -136.3 -105.6 232.7 43.1 H2O2Sn Tin(II) hydroxide -561.1 -491.6 155.0 H2O2Sr Strontium hydroxide -959.0 5- H O Zn Zinc hydroxide -641.9 -553.5 81.2 18 2 2 H2O3Si Metasilicic acid -1188.7 -1092.4 134.0 H2O4S Sulfuric acid -814.0 -690.0 156.9 138.9 H2O4Se Selenic acid -530.1 H2S Hydrogen sulfide -20.6 -33.4 205.8 34.2 H2S2 Hydrogen disulfide -18.1 84.1 15.5 51.5 H2Se Hydrogen selenide 29.7 15.9 219.0 34.7 H2Sr Strontium hydride -180.3 H2Te Hydrogen telluride 99.6 H2Th Thorium hydride -139.7 -100.0 50.7 36.7 H2Zr Zirconium(II) hydride -169.0 -128.8 35.0 31.0 H3ISi Iodosilane 270.9 54.4 H3N Ammonia -45.9 -16.4 192.8 35.1 H3NO Hydroxylamine -114.2 H3O2P Phosphinic acid -604.6 -595.4 H3O3P Phosphonic acid -964.4 H3O4P Phosphoric acid -1284.4 -1124.3 110.5 106.1 -1271.7 -1123.6 150.8 145.0 H3P Phosphine 5.4 13.5 210.2 37.1 H3Sb Stibine 145.1 147.8 232.8 41.1 H3U Uranium(III) hydride -127.2 -72.8 63.7 49.3 H4IN Ammonium iodide -201.4 -112.5 117.0 H4N2 Hydrazine 50.6 149.3 121.2 98.9 95.4 159.4 238.5 48.4 H4N2O2 Ammonium nitrite -256.5 H4N2O3 Ammonium nitrate -365.6 -183.9 151.1 139.3 OS Sulfur monoxide 6.3 -19.9 222.0 30.2 OSe Selenium monoxide 53.4 26.8 234.0 31.3 OSi Silicon monoxide -99.6 -126.4 211.6 29.9 OSn Tin(II) oxide -280.7 -251.9 57.2 44.3 15.1 -8.4 232.1 31.6 OSr Strontium oxide -592.0 -561.9 54.4 45.0 1.5 OFCHEMICALSUBSTANCES THERMODYNAMIC PROPERTIES STANDARD OTi Titanium(II) oxide -519.7 -495.0 50.0 40.0 OTl2 Thallium(I) oxide -178.7 -147.3 126.0 OU Uranium(II) oxide 21.0 OV Vanadium(II) oxide -431.8 -404.2 38.9 45.4 OZn Zinc oxide -350.5 -320.5 43.7 40.3 O2 Oxygen 0.0 205.2 29.4 O2P Phosphorus dioxide -279.9 -281.6 252.1 39.5 O2Pb Lead(IV) oxide -277.4 -217.3 68.6 64.6 O2Rb Rubidium superoxide -278.7 O2Rb2 Rubidium peroxide -472.0 O2Ru Ruthenium(IV) oxide -305.0 O2S Sulfur dioxide -320.5 -296.8 -300.1 248.2 39.9 O2Se Selenium dioxide -225.4 O2Si Silicon dioxide (a-quartz) -910.7 -856.3 41.5 44.4 -322.0 O2Sn Tin(IV) oxide -577.6 -515.8 49.0 52.6 O Te Tellurium dioxide -322.6 -270.3 79.5 TeamLRN 2 O2Th Thorium(IV) oxide -1226.4 -1169.2 65.2 61.8 5- O2Ti Titanium(IV) oxide -944.0 -888.8 50.6 55.0 23 O2U Uranium(IV) oxide -1085.0 -1031.8 77.0 63.6 -465.7 -471.5 274.6 51.4 O2WTungsten(IV) oxide -589.7 -533.9 50.5 56.1 O2Zr Zirconium(IV) oxide -1100.6 -1042.8 50.4 56.2 O3 Ozone 142.7 163.2 238.9 39.2 O3PbS Lead(II) sulfite -669.9 O3PbSi Lead(II) metasilicate -1145.7 -1062.1 109.6 90.0 O3Pr2 Praseodymium oxide -1809.6 117.4 O3Rh2 Rhodium(III) oxide -343.0 103.8 O3S Sulfur trioxide -454.5 -374.2 70.7 -441.0 -373.8 113.8 -395.7 -371.1 256.8 50.7 O3Sc2 Scandium oxide -1908.8 -1819.4 77.0 94.2 O3SiSr Strontium metasilicate -1633.9 -1549.7 96.7 88.5 O3Sm2 Samarium(III) oxide -1823.0 -1734.6 151.0 114.5 O3Tb2 Terbium oxide -1865.2 115.9 O3Ti2 Titanium(III) oxide -1520.9 -1434.2 78.8 97.4 O3Tm2 Thulium oxide -1888.7 -1794.5 139.7 116.7 O3U Uranium(VI) oxide -1223.8 -1145.7 96.1 81.7 O3V2 Vanadium(III) oxide -1218.8 -1139.3 98.3 103.2 O3WTungsten(VI) oxide -842.9 -764.0 75.9 73.8 O3Y2 Yttrium oxide -1905.3 -1816.6 99.1 102.5 O3Yb2 Ytterbium(III) oxide -1814.6 -1726.7 133.1 115.4 O4Os Osmium(VIII) oxide -394.1 -304.9 143.9 -337.2 -292.8 293.8 74.1 O4PbS Lead(II) sulfate -920.0 -813.0 148.5 103.2 O4PbSe Lead(II) selenate -609.2 -504.9 167.8.
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