Δ S total = Δ S sys + Δ S surr {\displaystyle \Delta S_{\mbox{total}}=\Delta S_{\mbox{sys}}+\Delta S_{\mbox{surr}}\,\!}
Δ S surr = − Δ H sys T {\displaystyle \Delta S_{\mbox{surr}}={\frac {-\Delta H_{\mbox{sys}}}{T}}}
Δ S total > 0 {\displaystyle \Delta S_{\mbox{total}}>0\,\!}