HW $-25($ii$)($See HW $-11($ii$))$

A closed, externally well$-$insulated rigid tank is divided into two parts by a partition. Initially one part contains $2\mathrm{.}5$ kg of liquid water at an absolute pressure of $6$ bar and a temperature of $\backslash (60^\{\backslash$circ$\}\backslash$mathrm$\{$C$\}\backslash )$ while the other part is perfectly evacuated $($State $1).$ The partition is removed and water expands to fill the entire tank to an absolute pressure of $0\mathrm{.}1$ bar $($State $2).$

Find the entropy change of water, in $\backslash (\backslash$mathrm$\{$kJ$\}/\backslash$mathrm$\{$K$\}\backslash ).$