Question

1. 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 flat, horizontal line a steep, downward sloping line a steep, upward sloping line

Explanation:

During a phase change (like melting or boiling), the temperature of a substance remains constant even though energy is being added. This is represented by a flat, horizontal line on a temperature - time graph. A steep upward - sloping line would indicate a rapid increase in temperature (like heating a substance in one phase), and a steep downward - sloping line would indicate a rapid decrease in temperature (like cooling a substance in one phase).

Answer:

a flat, horizontal line