Chemistry 9701 · AS & A Level · Chemical energetics

Chemical energetics — practice question

In solid sulfur, the molecules are each formed from eight atoms linked by covalent bonds. In sulfur dioxide, the bonding is $\text{O}=\text{S}=\text{O}$. The enthalpy change of combustion of $\text{S}_8$, $\Delta H_c^{\circ}(\text{S}_8(s)) = -2376\,\text{kJ mol}^{-1}$. The energy needed to separate $1.0\,\text{mol}$ $\text{S}_8(s)$ into gaseous atoms is $2232\,\text{kJ mol}^{-1}$. The $\text{O}=\text{O}$ bond enthalpy is $496\,\text{kJ mol}^{-1}$. From these data, determine the value of the $\text{S}=\text{O}$ bond enthalpy.

  • A$239\,\text{kJ mol}^{-1}$
  • B$257\,\text{kJ mol}^{-1}$
  • C$319\,\text{kJ mol}^{-1}$
  • D$536\,\text{kJ mol}^{-1}$

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