[QUE/TH-07005] TH-PROBLEM

 Liquid water having a mass of 10 kg and a temperature of
20$^\circ$C is mixed with 2 kg of ice at a temperature of
$-5^\circ$C at 1 atm pressure until equilibrium is reached. Compute
final temperature and the change in entropy of the system 

$ C_p\,\text{(water)}=4.18\times10^3 {\rm K}^{-1}{\rm kg}^{-1}~;~~
C_p{\rm (ice)}=2.09\times10^3{\rm J}\,{\rm kg}^{-1}{\rm K}^{-1}~;~
l_{12}=3.34\times10^5{\rm J}\,{\rm kg}^{-1}$