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Electron ny B65. Calculate the enthalpy change for the reaction Fe,O, + 3CO2Fe+ 3codata.2 3CO; AH 137 k]226 |
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Answer» A dash of simultaneous equationy stuff to begin, so we have 6 Fe in each of the first equations. (Fe2O3(s) + 3CO(g) => 2Fe(s) + 3CO2(g) ; Δ H = –28.0kJ) x33Fe2O3(s) + 9CO(g) => 6Fe(s) + 9CO2(g) and Δ H = –84.0kJ (Fe3O4(s) + 4CO(g) => 3Fe(s) + 4CO2(g) ; Δ H = –12.5kJ) x2 so2Fe3O4(s) + 8CO(g) => 6Fe(s) + 8CO2(g) and Δ H = –25.0kJ We know 3Fe2O3(s) is our starting product so the top reaction occurs in its original direction, and the other is reversed. 3Fe2O3(s) + 9CO(g) => 6Fe(s) + 9CO2(g)6Fe(s) + 8CO2(g) => 2Fe3O4(s) + 8CO(g) which is the same as the 3rd equation in the question. but now we know the directions. As the top equation keeps its original direction, Δ H keeps its sign. the other is reversed. it's essentially one reaction followed by the other, so -84 + 25 = -59kJ/mol |
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