Question

which statement about the physical change of liquid water boiling into steam is true? the heat added represents an energy change. the action cannot be reversed. the steam cannot conserve mass. the weight lost represents a mass change.

Explanation:

When liquid water boils into steam, heat is added to change the state from liquid to gas. This heat represents an energy - input for the phase change. The process is reversible (steam can condense back to water), mass is conserved according to the law of conservation of mass, and the weight loss is due to the water changing to a gaseous state and escaping, not a change in mass.

Answer:

The heat added represents an energy change.