A pure substance is heated at constant pressure from –20 °C to 30 °C. The temperature–time data show three distinct segments:
I. –20 °C to 0 °C (temperature rises)
II. 0 °C (temperature remains constant)
III. 0 °C to 30 °C (temperature rises)
Which segment represents an endothermic process in which the average kinetic energy of the particles does not change?
a) Segment III only
b) Segments I and III
c) Segment II only
d) Segment I only