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19 Chemical Thermodynamics Solutions to Exercises (c) Owing to strong hydrogen bonding interactions, water probably does not obey Trouton's rule. From Appendix B, at 100°C = = (d) Use = 88 J/mol-K, the middle of the range for Trouton's rule, to estimate for chlorobenzene. = T = 19.109 The activated complex in Figure 14.15 is a single "particle" or entity that contains four atoms. It is formed from an atom A and a triatomic molecule, ABC, that must collide with exactly the correct energy and orientation to form the single entity. There are many fewer degrees of freedom for the activated complex than the separate reactant particules, so the entropy of activation is negative. hv 19.110 (a) O₂(g) S increases because there are more moles of gas in the products. (b) O₂(g) + O(g) O₃(g), S decreases because there are fewer moles of gas in the products. (c) S increases as the gas molecules diffuse into the larger volume of the stratosphere; there are more possible positions and therefore more motional freedom. (d) NaCl(aq) NaCl(s) + decreases as the mixture (seawater, greater disorder) is separated into pure substances (fewer possible arrangements, more order). 19.111 (a) 16 pairs. The C-S bond order is approximately 2. (b) domains around C, linear domain geometry, linear molecular structure (c) + (d) = + - + = + - = The reaction is exothermic and spontaneous at 298 K. 607