An insulated rigid tank with a volume of 7 m³ contains steam at 500 kPa and 480 K and a hot 5-kg steel bar. The steel bar cools until the insulated system reaches an equilibrium temperature of 520 K. For the steel bar, use ρ = 7900 kg/m³ and c = 477 J/kg · K.

A. Determine the initial temperature of the steel bar.

B. Determine the change in entropy of the system during the process.

C. Why does the entropy increase in this process?