# What happen to the kinetic and potential energy during the boiling and melting?

• Chaos&Anarchy
In summary, the conversation discusses the relationship between kinetic and potential energy in substances, specifically in regards to boiling or melting. Substances are made up of constantly moving atoms or molecules, with temperature representing the average kinetic energy. The potential energy is related to the chemical connections between molecules. When substances come in contact, their kinetic energies will tend to equalize. Heat is the energy that is transferred during this process. During a change of state, heat is used to break the connections between molecules, resulting in a change in potential energy while kinetic energy remains the same. This energy is known as latent heat.
Chaos&Anarchy
I know this question is probably chicken feet to most of the people here, and I hope I am posting on the right thread. But I am just curious about 2 questions;

1 - Where does the kinetic and potential energy comes from in a substance?
2 - How are the kinetic and potential energy affected by boiling or melting?

Any reply would be a real help. Thanks =D

Substances are composed of atoms or molecules. They are in constant motion (vibrating or translating depending on the state of the substance).
Temperature is the average kinetic energy of a molecule of that substance.
There are connections between the molecules (chemical connections) - potential energy of the substance.
The whole energy of all the molecules (kinetic and potential) is the internal energy of the substance.
If you place another substance(2) in contact with the substance(1) the molecules of the two substances will come in contact and will tend to even their kinetic energies (temperatures).
Heat is the energy that has been transfered.
When a substance goes from one state to another the addition of heat does not increase the temperature of the substance but is used to brake the connections between molecules (to bring the molecules to higher potential level).

From this I hope you can answer those questions.

So basically, while the change of state is occurring only the amount of potential is changed while kinetic energy remains the same? Thanks a lot. That was really helpful.

Yes, that energy is called latent heat (heat of transformation).
I'm glad I was able to help.

During boiling and melting, both kinetic and potential energy are involved in the process. Kinetic energy is the energy of motion of individual particles, while potential energy is the energy stored in the bonds between particles.

1 - The kinetic and potential energy in a substance comes from the movement and interactions of its particles. At the atomic or molecular level, particles are constantly moving and interacting with each other. This motion and interaction results in the energy that we observe as kinetic and potential energy.

2 - During boiling, the kinetic energy of the particles increases as they gain enough energy to overcome the intermolecular forces holding them together. As the temperature increases, the kinetic energy of the particles also increases, causing them to move faster and further apart. This increase in kinetic energy leads to the conversion of the substance from a liquid to a gas.

During melting, the potential energy of the particles is affected. As the substance is heated, the particles gain enough energy to break the bonds holding them together in a solid state. This results in a decrease in potential energy and a corresponding increase in kinetic energy as the particles begin to move more freely. This change in energy state leads to the conversion of the substance from a solid to a liquid.

In both processes, the total energy of the system (kinetic + potential) remains constant. However, the distribution of this energy changes as the substance undergoes a phase change.

## 1. What happens to the kinetic and potential energy during boiling?

During boiling, the kinetic energy of the molecules increases as they gain more energy and begin to move faster. At the same time, the potential energy decreases as the intermolecular forces holding the molecules together weaken and eventually break. This leads to the phase change from liquid to gas.

## 2. What happens to the kinetic and potential energy during melting?

During melting, the kinetic energy of the molecules also increases as they gain energy and begin to vibrate more. However, the potential energy remains relatively constant as the intermolecular forces are still present, just weaker. This allows the solid to transition into a liquid state.

## 3. Does the total energy of a substance change during boiling or melting?

No, the total energy of a substance remains the same during boiling and melting. The increase in kinetic energy is balanced by the decrease in potential energy, resulting in no overall change in energy.

## 4. Why do substances require energy to boil and melt?

In order for a substance to change from one phase to another, energy is required to break the intermolecular bonds and overcome the forces holding the molecules together. This energy is known as the latent heat of fusion (for melting) or vaporization (for boiling).

## 5. Can potential and kinetic energy be converted into each other during boiling and melting?

Yes, potential and kinetic energy can be converted into each other during boiling and melting. As molecules gain or lose energy, their kinetic and potential energies change accordingly. However, the total energy of the system remains the same.

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