Question

a student heats a beaker of water and constructs a graph based on the recorded observations.
what can be concluded from the portion of the graph where the temperature remains constant?
the water in the beaker is boiling.
the water in the beaker is melting.
the water in the beaker is freezing.
the water in the beaker is condensing.

Explanation:

When a substance is heated and its temperature stays constant, this occurs during a phase change where heat energy is used to break intermolecular bonds rather than increase temperature. The initial substance is liquid water being heated, so the constant temperature phase change here is boiling (liquid to gas). Melting applies to solid water (ice) turning liquid, freezing is liquid to solid, and condensing is gas to liquid, none of which match the scenario of heating liquid water.

Answer:

The water in the beaker is boiling.