Consider the decomposition of liquid benzene, C6H6(l), to gaseous acetylene, C2H
ID: 760253 • Letter: C
Question
Consider the decomposition of liquid benzene, C6H6(l), to gaseous acetylene, C2H2(g): C6H6(l) -> 3 C2H2 (g) Change in Enthalpy = +630 kJ (a) What is the enthalpy change for the reverse reaction? (b) What is Change in Enthalpy for the formation of 1 mol of acetylene? (c) Which is more likely to be thermodynamically favored, the forward reaction of the reverse reaction? (d) If C6H6(g) were consumed instead of C6H6(l), would you expect the magnitude of Change in Enthalpy to increase,decrease, or stay the same? Explain. The following is my attempt to answer the problems: (a) -630 kJ (b) -630 kJ/ 3= -210 kJ (c) The reverse reaction? (d) C6H6(g) 82.9 Change in Hf kj/mol C6H6(g) 49.0 Change in Hf kj/mol The magnitude would increase ?Explanation / Answer
C6H6(l)----> 3 C2H2(g) Delta H= +630 kJ A) What is the enthalpy change for the reverse reaction? opposite reaction, has the opposite resultant energy change Your answer is : dH = -630kJ ================== B) What is the Delta H for the information of 1 mol of acetylene? your reaction did dH = +630kJ / 3 moles of acetylene produced, divide it to get kJ/mole your answer is: dH = 210kJ per 1 mole C2H2 ======================================… C) Which is more likely to be thermodynamically favired, the forward reaction or reverse reacion? favorable reactions lose energy, forming compound that are less energetic, are ones that are more stable the forward reaction is endothermic, increasing the energy of the chemicals, not helpful Your answer is : the reverse reaction because dH = -630kJ, is and exothermic reaction , & exothermic reactions are more favorable ========================== D) If C6H6(g) were consumed instead of C6H6(l), would you expect the magnitude of delta H to increase, decrease, or stay the same? explain. I would expect that the dH not to be as great as +630kJ. we have add some of that energy just to evaporate the benzene, if it comes pre-evaporated, we won't have to add as much energy, (the energy referred to as Heat of vaporization) your answer is: dH will be decreased ===================