Multiple Choice Question

Question

The graph below shows the phase change for H2O.

Which statement best describes what is occurring at segment C?
A.
As energy increases, the temperature remains the same.

B.
As energy increases, temperature also increases.

C.
As temperature increases, energy remains the same.

D.
Energy and temperature remain the same.

Answer 1

To determine the best description of what is occurring at segment C of the phase change graph for H2O, we need to understand what happens during the phase changes and plateaus in such a graph.

Typically, in a phase change graph:

• Segments where temperature increases (diagonal lines) indicate a temperature rise as energy is added (this corresponds to heating the substance).
• Segments where the line is flat (horizontal lines) indicate a phase change (e.g., melting or boiling), where the temperature remains constant despite the addition of energy.

If segment C is a plateau on the graph, this indicates a phase change, and thus the temperature remains the same as energy is added.

Given this information, the best answer that describes what is occurring at segment C (assuming it represents a plateau where a phase change is taking place) would be:

A. As energy increases, the temperature remains the same.