Question

a substance is placed in a closed vessel. the substance is continuously heated and its temperature is monitored, leading to the heating curve below. five regions of the heating curve are labeled with a number. heating curve graph: temperature (y - axis), time of heating (x - axis), regions labeled 1, 2, 3, 4, 5 during which numbered region(s) of the graph does the addition of heat lead to a state change? select all that apply. tap to select or deselect an answer. select all that apply. 1 2 3 4 5

Explanation:

In a heating curve, regions with constant temperature (horizontal segments) represent state changes (phase transitions) as heat energy is used for changing state (like melting or boiling) instead of increasing temperature. Region 2 and 4 are horizontal, so heat addition here causes state change. Region 1,3,5 have increasing temperature (heating of a single phase), no state change.

Answer:

2, 4