Question

which statement describes the appearance of a temperature - vs - time graph? a horizontal line shows that the temperature increases at a constant rate over time. a vertical line shows that the temperature decreases at a constant rate over time. horizontal lines where the temperature is constant during phase changes connect upward - sloping lines where the temperature increases. horizontal lines where the temperature increases are connected by upward - sloping lines where the temperature is constant for each phase.

Explanation:

In a temperature - vs - time graph, during phase changes (like melting or boiling), the temperature remains constant, which is represented by horizontal lines. Between phase changes, when the substance is in a single phase and being heated or cooled, the temperature increases or decreases and is represented by upward - sloping or downward - sloping lines respectively.

Answer:

Horizontal lines where the temperature is constant during phase changes connect upward - sloping lines where the temperature increases.