Question

use the diagram below to answer the following question.
what phase change is occurring from \d to e\?
melting point
boiling point
condensation
freezing point

Explanation:

1. First, analyze the heating curve: In a heating curve, a horizontal segment (constant temperature) indicates a phase change.
2. From D to E, temperature is constant while heat is being removed or added? Wait, no—wait, the y - axis is temperature, x - axis is time. Wait, actually, in a heating curve (adding heat over time), but if we consider cooling, but the labels: Wait, phase changes: Melting is solid to liquid (B - C, if B - C is melting). Boiling is liquid to gas (D - E? No, wait, no—wait, when temperature is constant during phase change:

• Melting: solid to liquid (temperature constant at melting point).
• Boiling: liquid to gas (temperature constant at boiling point).
• Condensation: gas to liquid (temperature constant at boiling point, releasing heat).
• Freezing: liquid to solid (temperature constant at freezing point).

Wait, the segment D - E: if we assume the substance is cooling (but the graph has F going up, maybe it's a heating - cooling? No, the x - axis is time, y - axis temperature. Wait, maybe the curve is a heating curve with some cooling? No, the labels: A to B: heating solid, B to C: melting (solid to liquid, constant temp), C to D: heating liquid, D to E: condensing? Wait, no—wait, the options: condensation is gas to liquid. Let's recall:

• Melting point: temperature at which melting occurs (not a phase change process).
• Boiling point: temperature at which boiling occurs (not a process).
• Condensation: gas to liquid (phase change, releases heat, temperature constant at boiling point).
• Freezing point: temperature at which freezing occurs (not a process).

So from D to E, if the temperature is constant, and assuming that D is the boiling point (liquid to gas is boiling, but if we are going from D to E, maybe it's cooling, so gas to liquid is condensation. Wait, the options: the options are "melting point" (not a process), "boiling point" (not a process), "condensation" (process), "freezing point" (not a process). So the phase change process from D to E (constant temperature) must be condensation (gas to liquid), because boiling is liquid to gas (but if we are cooling, after boiling (liquid to gas at D), then cooling the gas would condense to liquid at constant temperature (boiling point). So the correct process is condensation.

Answer:

condensation