Final answer:
The sections of the heating curve that demonstrate an increase in the kinetic energy of water molecules while overcoming molecular attractions are the melting and boiling phases, distinguished by flat line segments at constant temperatures of 0°C and 100°C respectively.
Step-by-step explanation:
The process of heating a sample of water that leads to an increase in the kinetic energy of its molecules while overcoming attractions between the molecules occurs during two key stages on a heating curve. The first is during the melting phase where the solid converts to liquid at a constant temperature of 0°C, which corresponds to a flat section of the curve. The second is during the boiling phase where liquid changes to gas, also at a constant temperature, but this time at 100°C. Each of these sections represents an increase in kinetic energy without an increase in temperature as the added energy is used to overcome molecular attractions rather than increase motion.