Calculate the changes in total entropy of the universe as a result of the following processes:
(a) A block of mass 6kg and heat capacity of 300 J/K/kg at 150oC is placed in a lake at 0oC.
The Attempt at a Solution
I think I have found the entropy change of the block as -788 J/K. I am not sure how to find the entropy change of the lake though as I don't know the mass.
Thanks for any help.