A $15-$kg iron block initially at $280C$ is quenched in an insulated tank that contains $100kg$ of water at $18C.$ Assuming the water that

vaporizes during the process condenses back in the tank, determine the total entropy change during this process. The specific heat of

water at $25C$ is $c_p=4\mathrm{.}18k\frac{J}{k}g*K.$ The specific heat of iron at room temperature is $c_p=0\mathrm{.}45k\frac{J}{k}g*K.$

The total entropy change during this process is

$k\frac{J}{K}.$