At the reaction has

CHEMISTRY · Subjective · A Level · Chemistry · Thermodynamics · Thermodynamics

Problem

298\,\text{K}

the reaction

\mathrm{Mg(s)+2\,HCl(aq)\;\rightarrow\;MgCl_2(aq)+H_2(g)}

has

\Delta S^{\circ}_{\text{rxn}} = -0.128\,\text{kJ\,mol}^{-1}\,\text{K}^{-1}

. The following standard molar entropies are known:

S^{\circ}\!(\mathrm{MgCl_2(aq)}) = 93.1\;\text{J\,mol}^{-1}\,\text{K}^{-1}

S^{\circ}\!(\mathrm{H_2(g)}) = 130.7\;\text{J\,mol}^{-1}\,\text{K}^{-1}

, and

S^{\circ}\!(\mathrm{HCl(aq)}) = 56.5\;\text{J\,mol}^{-1}\,\text{K}^{-1}

. Determine the standard molar entropy of

\mathrm{Mg(s)}

298\,\text{K}