As a substance goes from a solid to a liquid, the particles

move further apart?

duh

For many substances, yes. It depends on the density of the solid/liquid. What does happen, is that in solids atoms are mostly bound in a crystal arrangement, and not free to move except in a vibrational mode. In a liquid, the atoms can move about.

Here is a step-by-step breakdown of what happens as a substance goes from a solid to a liquid:

1. In a solid, the particles (atoms, molecules, or ions) are tightly packed and arranged in a ordered or regular pattern. The attractive forces between particles keep them in fixed positions, and they can only vibrate around these positions.

2. When heat is supplied to the solid, the particles start to gain kinetic energy. This kinetic energy enables them to overcome the attractive forces holding them together.

3. As the temperature continues to rise, the particles gain more energy and start to vibrate more vigorously. This causes the bonds between particles to weaken.

4. Eventually, at a certain temperature called the melting point, the particles gain enough energy to completely overcome the attractive forces holding them in place. At this point, the solid starts to change into a liquid.

5. In the liquid state, the particles have enough energy to move around each other but are still close together. They are not arranged in a fixed pattern like in a solid.

6. Because the particles in a liquid have more freedom of movement, they tend to move further apart compared to the solid state. This increase in distance between the particles results in an increase in volume.

It's important to note that not all substances behave the same way when transitioning between solid and liquid states. Some substances, like water, actually have a denser, more compact arrangement in the solid state compared to the liquid state due to the unique structure of their molecules.

To understand why this happens, we need to look at the nature of the particles in a substance and their behavior as it transitions from a solid to a liquid.

In a solid, the particles (atoms, molecules, or ions) are tightly packed and arranged in a regular, ordered pattern called a crystal lattice. The particles vibrate in fixed positions around their equilibrium positions due to thermal energy. These vibrations keep the solid intact and give it a definite shape and volume.

When heat is added to the solid, its temperature increases. This causes the particles to gain more energy, leading to an increase in their vibrational motion. As the temperature rises, the particles vibrate with greater amplitude and kinetic energy.

At a specific temperature called the melting point, the energy supplied to the solid overcomes the intermolecular forces holding the particles together in the crystal lattice. As a result, the solid starts to transform into a liquid.

In the liquid state, the particles become more mobile. The increased thermal energy allows the particles to move around and slide past each other more freely. While the intermolecular forces still exist, they are not strong enough to keep the particles fixed in a specific position like in a solid.

Therefore, as a substance transitions from a solid to a liquid, the particles do indeed move further apart on average. This increase in particle mobility and the resultant expansion of volume is the reason why most substances expand when they undergo this phase change.