19. • What is the change in entropy of mercury vapor

(Lv = 2.7 × 105 J/kg) when 0.50 kg of it condenses to a liquid at its boiling point of 357 °C?

20. IE • 2.0 kg of ice melts completely into liquid water at 0 °C.

(a) The change in entropy of the ice (water) in this process is (1) positive, (2) zero, (3) negative. Explain.

(b) Compute the change in entropy of the ice (water).