Question

1. What has to be added to a substance to cause a phase change?

Answer 1

Phase changes require either the addition of heat energy (melting, evaporation, and sublimation) or subtraction of heat energy (condensation and freezing). ... Changing the amount of heat energy usually causes a temperature change.

Answer 2

To cause a phase change, you either add heat energy to a substance to cause it to evaporate, melt, or sublimate, or you subtract heat energy, or take it away, to make the substance freeze or condense. Hope it helps!

Step-by-step explanation: