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. 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:

During a state change (e.g., melting or boiling), the temperature of a substance remains constant while heat is being added. This is because the energy is used to break intermolecular forces rather than increase the kinetic energy (temperature). In the heating curve, regions where the temperature is constant (horizontal lines) correspond to state - change processes.

Answer:

2, 4