Q1 Combustion of ethanol. The Lewis Structure of the molecule ethanol is presented in Figure Q1.1....

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Q1 Combustion of ethanol. The "Lewis Structure" of the molecule ethanol is presented in Figure Q1.1. How many electron bonding pairs and electron lone pairs are present in the molecule? How many electrons is this in total? [2] (a) (b) (c) (d) H H H H-C-C H H Figure Q1.1 Lewis structure of Ethanol -H Carbon (C) has 4 electrons on its valence shell whilst hydrogen (H) has 1 and oxygen (0) has 6. How many valence electrons are there in ethanol? [2] The reaction of combustion of ethanol is presented in the reaction equation below. Balance the equation. [2] C₂H5OH(g) + O2(g) = CO2(g) + H₂O(g) In Table Q1.1, the energy for single bonds between common atoms are presented. Breaking bonds requires energy while forming bonds releases energy. Using Table 1, show that the energy required for the breaking of all the bonds in ethanol is equal to 3232kJ/mol. [5] (e) Single Bond Energies (kJ/mol of bonds) HCNOSF CI Br H 436 C 413 346 N 391 305 163 O 463 358 201 146 S 347 272 226 F 565 485 283 190 284 155 Cl 432 339 192 218 255 253 242 Br 366 285 201 217 249 216 193 I I 299 213 201 278 208 175 151 Table Q1.1 Single Bond Energies between Common Atoms Calculate the total energy, Eºbr, needed to break all the reactant bonds during the combustion of ethanol. (Don't forget about the stochiometric coefficients). [2] (f) (h) In Table Q1.2, the total energy of the bonds in O2, CO2 and H₂O are presented are presented. Calculate the total energy, Eºfo, released by the forming of all the products bonds. (Don't forget about the stochiometric coefficients). [2] CO₂ H₂O 498kJ/mol 1486kJ/mol 926kJ/mol Table Q1.2 Total bond energies for various compounds 0₂ Ho for the reaction is -1024kJ/mol. Compare with Eºbr - Eºfo and explain. Does this reaction produce or consume heat? What are such reactions called? [3] Table Q1.3 presents the AG°f for each of the compounds involved in the combustion of ethanol. Calculate AGO for the reaction. Is the reaction spontaneous? (Don't forget about the stochiometric coefficients). [2] C₂H5OH(g) AG% -167.9kJ/mol O2(g) AGO=0kJ/mol CO2(g) H₂O(g) AG=-394.4kJ/mol AG-228.6 KJ/mol Table Q1.3 4Gº for products and reactants in the combustion of ethanol (k) Calculate the standard change in entropy ASO for this reaction at 25°C. Explain why the entropy is positive. Q1 Combustion of ethanol. The "Lewis Structure" of the molecule ethanol is presented in Figure Q1.1. How many electron bonding pairs and electron lone pairs are present in the molecule? How many electrons is this in total? [2] (a) (b) (c) (d) H H H H-C-C H H Figure Q1.1 Lewis structure of Ethanol -H Carbon (C) has 4 electrons on its valence shell whilst hydrogen (H) has 1 and oxygen (0) has 6. How many valence electrons are there in ethanol? [2] The reaction of combustion of ethanol is presented in the reaction equation below. Balance the equation. [2] C₂H5OH(g) + O2(g) = CO2(g) + H₂O(g) In Table Q1.1, the energy for single bonds between common atoms are presented. Breaking bonds requires energy while forming bonds releases energy. Using Table 1, show that the energy required for the breaking of all the bonds in ethanol is equal to 3232kJ/mol. [5] (e) Single Bond Energies (kJ/mol of bonds) HCNOSF CI Br H 436 C 413 346 N 391 305 163 O 463 358 201 146 S 347 272 226 F 565 485 283 190 284 155 Cl 432 339 192 218 255 253 242 Br 366 285 201 217 249 216 193 I I 299 213 201 278 208 175 151 Table Q1.1 Single Bond Energies between Common Atoms Calculate the total energy, Eºbr, needed to break all the reactant bonds during the combustion of ethanol. (Don't forget about the stochiometric coefficients). [2] (f) (h) In Table Q1.2, the total energy of the bonds in O2, CO2 and H₂O are presented are presented. Calculate the total energy, Eºfo, released by the forming of all the products bonds. (Don't forget about the stochiometric coefficients). [2] CO₂ H₂O 498kJ/mol 1486kJ/mol 926kJ/mol Table Q1.2 Total bond energies for various compounds 0₂ Ho for the reaction is -1024kJ/mol. Compare with Eºbr - Eºfo and explain. Does this reaction produce or consume heat? What are such reactions called? [3] Table Q1.3 presents the AG°f for each of the compounds involved in the combustion of ethanol. Calculate AGO for the reaction. Is the reaction spontaneous? (Don't forget about the stochiometric coefficients). [2] C₂H5OH(g) AG% -167.9kJ/mol O2(g) AGO=0kJ/mol CO2(g) H₂O(g) AG=-394.4kJ/mol AG-228.6 KJ/mol Table Q1.3 4Gº for products and reactants in the combustion of ethanol (k) Calculate the standard change in entropy ASO for this reaction at 25°C. Explain why the entropy is positive.

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1 Electronic configuration of various atom in ethanol molecule Carbon C 1s2 2s2 2p2 Hydrogen H 1s1 Oxygen O 1s2 2s2 2p4 Number of electrons in various atoms C 6 H 1 O 8 Number of valence electrons ele... View the full answer