Two blocks of the same metal and mass are at different initial temperatures T1 and T2. The blocks are brought into contact and come to a final temperature Tf. Assume the system is totally isolated from the surroundings and that the surroundings are at equilibrium. a. Your intuition probably tells you that for 2 identical blocks, Tf is the average of the initial temperatures, so that Tf = 1/2 (T1 + T2). Show that for a system of two blocks totally isolated from the surroundings that this is true. b. Show that the change in entropy is ?S = CP ln T1 + T2 ( )2 4T1 T2 c. How does this expression show that this process is spontaneous?