As a solid melts, the molecules _________ and have _______ attraction for one another.
a) move together, more
b) move apart, more
c) move apart, less
d) move together, less
e) get larger, greater
The correct answer and explanation is :
The correct answer is:
c) move apart, less
Explanation:
When a solid melts, it undergoes a phase transition from a solid state to a liquid state. To understand this, we need to consider the behavior of molecules in solids and liquids, as well as the forces that influence them.
In a solid, molecules are arranged in a tightly packed structure, often in a regular, repeating pattern. These molecules vibrate but do not move freely, because the attractive forces between them (such as ionic, covalent, or van der Waals forces) are strong enough to hold them in place. These strong intermolecular forces are responsible for the solid’s rigid structure.
As heat is applied to the solid, the energy increases the vibrations of the molecules. Once the temperature reaches the melting point, the energy provided overcomes some of the attractive forces between the molecules. This allows the molecules to break free from their fixed positions and begin to move around each other, transitioning into a more disordered arrangement typical of a liquid.
During this process, the molecules move apart because the energy from the heat reduces the strength of the attractive forces between them. In a liquid, the molecules are still attracted to each other, but not as strongly as in the solid state. This weaker attraction allows the molecules to move freely but still maintain some interaction, which is why liquids can flow but retain volume.
The lesser attraction between the molecules in the liquid state is a key characteristic of the melting process. The stronger forces that held the molecules tightly together in the solid state are weakened, making the molecules less bound to each other. This transition from stronger to weaker intermolecular forces and from close-packed to more spread-out molecules is what characterizes the melting of a solid.
Thus, as a solid melts, the molecules move apart and have less attraction for one another.