Question

A graph shows how the temperature of a substance changes as energy is added steadily over time.

Which part of the graph would indicate a phase change is taking place?
a steep, downward sloping line
a flat, horizontal line
a steep, upward sloping line

Answer 1

horizontal line

Step-by-step explanation:

Answer 2

A flat, horizontal line

Step-by-step explanation:

A flat, horizontal line indicates a phase change.

The temperature does not increase because the added heat goes into converting one phase into another.

A is wrong. A downward-sloping line indicates that the temperature is decreasing with time.

C is wrong. An upward-sloping line indicates that the temperature is increasing with time.