anon_ch posted a question
1) At constant pressure, the sign of q for the process H2O(l)->H2O(s) is expected to be: a)negative, and the process is endothermic. b)positive, and the process is exothermic. c)positive, and the process is endothermic. d)negative, and the process is exothermic. e)impossible to predict. 2)Which of the following reactions corresponds to the thermochemical equation for the standard enthalpy of formation of N,N-diethyl-m-toluamide, C12H17NO(l), the active ingredient in some insect repellants? a)12C(s) + 17H(g) + N(g) + O(g) -> C12H17NO(l) b)12C(s) + 17/2 H2(g) + 1/2 N2(g) + 1/2 O2(g) ® C12H17NO(l) c)12C(g) + 17H(g) + N(g) + O(g) -> C12H17NO(l) d)12C(g) + 17H(g) + N(g) + O(g) -> C12H17NO(g) e)12C(l) + 17H(l) + N(l) + O(l) -> C12H17NO(l) 3)H2 and F2 react according to the following equation, forming HF. H2(g) + F2(g) -> 2HF(g); DH° = –271 kJ If H2(g) and F2(g) were mixed in a thermally insulated vessel, the reaction that occurred would be: a)exothermic, and the temperature of the reaction system would rise. b)endothermic, and the temperature of the reaction system would rise. c)endothermic, and the temperature of the reaction system would fall. d)exothermic, and the temperature of the reaction system would fall. e)We could not tell unless the original and final temperatures were given.
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1) At constant pressure, the sign of q for the process H2O(l)->H2O(s) is expected to be:
a)negative, and the process is endothermic.
b)positive, and the process is exothermic.
c)positive, and...