Question

Calculate the standard entropy change of the surrounding if standard enthalpy of formation of methyl alcohol is –240 kJ mol^-1.

Options

• 706.48 J K^-1

• 805.37 J K^-1

• 915.10 J K^-1

• 612.16 J K^-1

Answer 1

805.37 J K^-1

Explanation:

ΔH° is defined at standard conditions where T must be 298 K.

\[\begin{aligned} \Delta\mathrm{S}_{\mathrm{surr}} & =-\frac{\Delta\mathrm{H}^{\circ}}{\mathrm{T}}=-\frac{\left(-240\mathrm{kJ}\right)}{298\mathrm{K}} \\ & =0.80537\mathrm{kJ}\mathrm{K}^{-1}=805.37\mathrm{J}\mathrm{K}^{-1} \end{aligned}\]