“During heating that causes a phase change, absorbed latent heat can increase a substance's internal potential energy by separating particles against their attractive intermolecular forces.”

When a substance being heated or cooled reaches a temperature corresponding to one of its phase transitions, further gain or loss of heat is a result of diminishing or enhancing intermolecular attractions, instead of increasing or decreasing molecular kinetic energies.

Energy is required to melt a solid because the cohesive bonds between the molecules in the solid must be broken apart such that, in the liquid, the molecules can move around at comparable kinetic energies; thus, there is no rise in temperature. … Similarly, energy is needed to vaporize a liquid, because molecules in a liquid interact with each other via attractive forces. … Figure 14.7 (a) Energy is required to partially overcome the attractive forces between molecules in a solid to form a liquid. That same energy must be removed for freezing to take place. (b) Molecules are separated by large distances when going from liquid to vapor, requiring significant energy to overcome molecular attraction.

Energy is required to melt a solid because the cohesive bonds between the molecules in the solid must be broken apart such that, in the liquid, the molecules can move around at comparable kinetic energies; thus, there is no rise in temperature. … Similarly, energy is needed to vaporize a liquid, because molecules in a liquid interact with each other via attractive forces. … Energy is required to partially overcome the attractive forces between molecules in a solid to form a liquid.

Instead, the additional thermal energy acts to loosen bonds between molecules or atoms and causes a phase change. Because this energy enters or leaves a system during a phase change without causing a temperature change in the system, it is known as latent heat (latent means hidden). … Energy is required to melt a solid because the bonds between the particles in the solid must be broken. Since the energy involved in a phase changes is used to break bonds, there is no increase in the kinetic energies of the particles, and therefore no rise in temperature. Similarly, energy is needed to vaporize a liquid to overcome the attractive forces between particles in the liquid.

Microscopic potential energy is associated with forces that bind masses together. It takes energy to pull two masses apart and break their bonds. This is analogous to increasing the microscopic potential energy of the system. … Latent energy is associated with phase change (solid, liquid, gas). … Further addition of energy forces bonds of the solid lattice to stretch, enabling more fluid movement of the molecules. This is melting, a latent effect that occurs with no temperature change.

At the temperature where a phase change occurs (such as melting or boiling), the temperature remains constant even though heat is still being added. … During these flat regions (plateaus), the heat goes into overcoming intermolecular forces, not increasing the kinetic energy of the molecules.

When a substance being heated or cooled reaches a temperature corresponding to one of its phase transitions, further gain or loss of heat is a result of diminishing or enhancing intermolecular attractions, instead of increasing or decreasing molecular kinetic energies.

For example, when water evaporates, an input of energy is required for the water molecules to overcome the forces of attraction between them and make the transition from water to vapor. … Later, James Prescott Joule characterised latent energy as the energy of interaction in a given configuration of particles, i.e. a form of potential energy, and the sensible heat as an energy that was indicated by the thermometer, relating the latter to thermal energy.

On a microscopic level melting or vaporization involves separating molecules which are attracted to each other. … Heat energy is absorbed to vaporize a liquid because molecules which are held together by intermolecular forces in the liquid are separated as the gas is formed.

When a substance being heated or cooled reaches a temperature corresponding to one of its phase transitions, further gain or loss of heat is a result of diminishing or enhancing intermolecular attractions, instead of increasing or decreasing molecular kinetic energies.

Eventually, when the ice has warmed to \(0^\text{o} \text{C}\), the added energy will start to break apart the hydrogen bonding that keeps the water molecules in place when it is in the solid form. As the ice melts, its temperature does not rise. All of the energy that is being put into the ice goes into the melting process and not into any increase in temperature.

Latent heat energy transferred to or from a substance during a change in its physical state that occurs without changing its temperature

In the process of vaporization of water, a large amount of energy must be added to overcome the remaining cohesive forces between the molecules and an additional amount of energy goes into PdV work to expand the gas from its very small liquid volume to the volume occupied by the resulting vapor.

Energy is required to melt a solid because the cohesive bonds between the molecules in the solid must be broken apart such that, in the liquid, the molecules can move around at comparable kinetic energies; thus, there is no rise in temperature. … Similarly, energy is needed to vaporize a liquid, because molecules in a liquid interact with each other via attractive forces. … Molecules are separated by large distances when going from liquid to vapor, requiring significant energy to overcome molecular attraction.

Changes of state are discussed in much greater depth in physics, looking at the internal energy of substances, delineating kinetic and potential energies.

In a liquid, the particles are not held as tightly because some of the intermolecular forces are broken. This means the particles can move past each other, allowing the liquid to flow.

The term latent means “hidden,” referring to the fact that this energy is not observable as a temperature rise but is stored as potential energy within the structure of the material. … Instead, potential energy increases as intermolecular bonds are broken or weakened. … During boiling, molecules completely overcome cohesive forces, moving apart to form a gas.

On the enthalpy side, we are determining how much energy it takes to increase the internal energy from solid to liquid (in a solid the molecules are in a lower potential energy configuration than the liquid so the internal energy is lower), and to make space in the environment for the liquid phase (the p∆V term).

Then in liquids and solids there is potential energy associated with the intermolecular attractive forces. A simplified visualization of the contributions to internal energy can be helpful in understanding phase transitions and other phenomena which involve internal energy.

The Particle model worksheets cover the following topics: - states of matter - arrangement of particles in solids, liquids and gases - names of state changes - relative energy of particles in solids, liquids and gases - changes in the kinetic energy when substances change state

The energy is transferred to the molecules or particles and they use it to overcome the intermolecular forces of attraction holding them in their solid or liquid state. Physicists call this latent heat.

This means that the heating, all that energy being input to the substance, had gone into increasing the potential energy of the particles and nowhere else. The potential energy of the particles have increased because it takes energy to pull molecules apart, due to the intermolecular forces trying to pull them together.

(2) latent energy. This is the energy associated with the attraction between molecules. We concern ourselves with latent energy most often when examining processes that involve a change of phase, such as going from a solid to a liquid or from a liquid to a gas (or vice versa).

When a substance is heated: - Kinetic energy increases → particles move faster - Potential energy may increase → particles move further apart (during state change)

Why negative potential energy? … More detail about energy changes

It is possible to define latent energy as the average intermolecular potential energy, but such a quantity is not directly related to latent heat.