Vi dụ: Tính Delta S_(298)^0 ? a) 2Mg_((r))+CO_(2(k))arrow 2MgO_((r))+C_((gr)) S_(298)^0(J/mol.K 32,5 213,8 26,78 5,69 b) 2CO_((k))+2NO_((k))arrow N_(2(k))+2CO_(2(k)) S_(298)^0(J/mol.K) 197,7 210.8 191.6 213.8

**a) $2Mg_{(r)}+CO_{2(k)}\rightarrow 2MgO_{(r)}+C_{(gr)}$**<br /><br />$\Delta S_{298}^{0} = \sum S_{298}^{0}(sp) - \sum S_{298}^{0}(cd)$<br /><br />$= [2.S_{298}^{0}(MgO) + S_{298}^{0}(C)] - [2.S_{298}^{0}(Mg) + S_{298}^{0}(CO_2)]$<br /><br />$= [2.26,78 + 5,69] - [2.32,5 + 213,8]$<br /><br />$= \boxed{-217,43 J/mol.K}$ <br />