A 200-gram block of aluminum (Al, 27 g/mole) with an initial temperature T_Al = 76.85 °C is brought into contact with a 500-gram block of copper (Cu, 63.5 g/mole) with an initial temperature T_Cu = 26.85 °C. Together the two blocks reach a final equilibrium temperature T_F.

Assume that the blocks only exchange heat with one another, and that the blocks do not change in volume.

Let T_F be the final temperature calculated using the Einstein model of solids where each metal block can be treated as a three dimensional lattice of balls on springs. The drawing shows two dimensions of the 3-dimensional lattice. Atoms (red balls) oscillate around their nominal positions (blue dots). Springs represent the potential V = (k/2) (x² + y² + z²). In this approximation, we find the heat capacity at constant volume using the equipartition theorem.

What is the final temperature of the two blocks in this approximation?

T_F = °C