temperature change during phase changes

[605720459 1I]

Can someone explain why the temperature stays constant during a phase change? It seems counterintuitive to me.

[elliemehrara]

The temperature stays constant during a phase change because, during this time, all of the heat added to the system is going towards changing the molecules from one state to another by moving them farther apart. On the other hand, when a system is not undergoing a phase change, all of the heat being added to the system is going towards making the molecules move faster, therefore increasing the temperature of the system.

[Rachel Fox - 3F]

The temperature stays constant during phase changes because the energy that would be used to increase the temperature is instead being used to increase the thermal motion of the molecules and therefore allowing the substance to change phase. This is why there are values for heat of fusion and heat of vaporization, as it takes the input of heat to change phase.

[Hannah Carsey 1B]

Temperature remains constant during phase change because at that point, any energy added to the substance is used to change the substance’s phase rather than to change the temperature. In other words, during phase change, the distance between the molecules changes, but not the velocity of such molecules or particles. Since the energy involved in a phase change is used to break bonds, there is no increase in the kinetic energies of the particles, and therefore no rise in temperature.

[Lawrence Tran 2H]

Temperature is the measurement of the motion of particles in a substance. When the substance is not undergoing a phase change, heat energy that is applied or removed increases or decreases the speed of the particles. During a phase change however, the change in heat energy goes towards changing the bonding of molecules to each other within a substance. Thus, temperature does not change until all the molecules within the substance have converted from one state to another.