Chemistry 9701 · AS & A Level · Chemical energetics

Chemical energetics — practice question

In an experiment, a student set out to determine the enthalpy change of combustion of ethane. He took the following values for the standard enthalpy changes of combustion of carbon and hydrogen. $\Delta H_c^{\circ}(\text{carbon}) = -394\,\text{kJ mol}^{-1}$ $\Delta H_c^{\circ}(\text{hydrogen}) = -286\,\text{kJ mol}^{-1}$ From his calculations, the enthalpy change of formation of ethane was found to be $-140\,\text{kJ mol}^{-1}$. What experimental value did he obtain for the standard enthalpy change of combustion of ethane?

  • A$-2364\,\text{kJ mol}^{-1}$
  • B$-1506\,\text{kJ mol}^{-1}$
  • C$-1112\,\text{kJ mol}^{-1}$
  • D$-540\,\text{kJ mol}^{-1}$

Worked solution & mark scheme

This 1-mark question has a full step-by-step worked solution and mark scheme.

  • Full mark scheme, point by point
  • Step-by-step worked solution
  • Write your answer & get it marked instantly by AI