Considere a reação: CHX4(g)+2 FX2(g)→CHX2FX2(g)+2 HF(g) \ce{ CH4(g) + 2 F2(g) -> CH2F2(g) + 2 HF(g) }

Assinale a alternativa que mais se aproxima da entalpia de reação.

Dados

  • ΔHL(HF)=565 kJmol\Delta H_\mathrm{L}(\ce{HF}) = \pu{565 kJ//mol}
  • ΔHL(FX2)=158 kJmol\Delta H_\mathrm{L}(\ce{F2}) = \pu{158 kJ//mol}
  • ΔHL(C−F)=484 kJmol\Delta H_\mathrm{L}(\ce{C-F}) = \pu{484 kJ//mol}
  • ΔHL(C−H)=412 kJmol\Delta H_\mathrm{L}(\ce{C-H}) = \pu{412 kJ//mol}
Gabarito 3X.06

ΔH=4ΔHL(C−H)+2ΔHL(FX2)−(2ΔHL(C−H)+2ΔHL(C−F)+2ΔHL(HF))\Delta H=4\Delta H_L(\ce{C-H})+2\Delta H_L(\ce{F2})-(2\Delta H_L(\ce{C-H})+2\Delta H_L(\ce{C-F})+2\Delta H_L(\ce{HF})) ΔH=2⋅412 kJmol+2⋅158 kJmol−2⋅484 kJmol−2⋅565 kJmol\Delta H=2\cdot\pu{412 kJ//mol}+2\cdot\pu{158 kJ//mol}-2\cdot\pu{484 kJ//mol}-2\cdot\pu{565 kJ//mol} ΔH=−958 kJmol\Delta H=\pu{-958 kJ//mol}