Question

water phase change graph
what is the boiling point of water?
what is the melting point and freezing point of water?
what phase change is at point b?
what phase change is at point d?
the states of matter

Explanation:

Step1: Boiling Point of Water

From the graph, the horizontal segment at 100°C (where phase change to gas starts) is the boiling point. So boiling point is 100°C.

Step2: Melting/Freezing Point of Water

The horizontal segment at 0°C (where solid melts to liquid) is the melting point (and freezing point, as melting and freezing are reverse processes at same temp). So melting/freezing point is 0°C.

Step3: Phase Change at Point B

Point B is on the horizontal segment at 0°C, where solid (ice) turns to liquid (water). This is melting (fusion).

Step4: Phase Change at Point D

Point D is on the horizontal segment at 100°C, where liquid (water) turns to gas (steam). This is boiling (vaporization).

Answer:

Boiling point of water: \( 100^\circ\text{C} \)
Melting point and freezing point of water: \( 0^\circ\text{C} \)
Phase change at point B: Melting (Fusion)
Phase change at point D: Boiling (Vaporization)