Explain why the potential energy increases when ice starts to melt an becomes liquid water.
The particles form a more ordered structure, reducing potential energy.
The particles slow down, reducing kinetic energy.
The particles get closer together, reducing potential energy.
The particles gain kinetic energy, increasing their freedom to move.
The correct explanation is: The particles gain kinetic energy, increasing their freedom to move.
When ice melts and becomes liquid water, the intermolecular forces holding the ice lattice structure together weaken and break. This allows the particles (water molecules) to move more freely and increases their kinetic energy. The increased freedom of movement and kinetic energy is associated with an increase in the system's entropy (disorder). In this process, the potential energy remains relatively constant as the interactions between the water molecules are primarily determined by their position and arrangement. Therefore, the potential energy does not contribute significantly to the increase when ice starts to melt and becomes liquid water.
so A B C or D?
The correct answer is D. The particles gain kinetic energy, increasing their freedom to move.
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Quick Check: Matter and Temperature
Blended Science 8 (5A/5B) - QUARTER 2 / Thermal Energy
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3.
If there has been an increase of potential energy in the molecules of a substance, what has occurred?
The substance has cooled down.
The substance has undergone a phase change.
The substance has evaporated.
The substance has gained kinetic energy.
The correct answer is D. The substance has gained kinetic energy.
When there is an increase in potential energy in the molecules of a substance, it implies that the molecules have gained energy, which is typically associated with an increase in kinetic energy. This increase in kinetic energy results in faster movement, greater freedom of motion, and higher temperatures.
When ice starts to melt and becomes liquid water, the potential energy of the particles increases. To understand why, let's take a closer look at the molecular level.
In a solid, like ice, the water molecules are arranged in a highly ordered and structured pattern. These molecules are held together by intermolecular forces, which create a stable lattice structure. The potential energy of the system is at a minimum because the particles are tightly packed in a specific arrangement.
When heat is added to the ice, the temperature begins to rise. As the temperature increases, the kinetic energy of the particles also increases. This increased kinetic energy allows the water molecules to vibrate and move more rapidly, loosening their connections to the lattice structure.
As the ice reaches its melting point, the heat energy breaks the intermolecular forces, and the water molecules transition from a fixed lattice arrangement to a more disordered state in liquid form. This transition requires energy, known as the latent heat of fusion, to overcome the forces holding the particles together in the solid state.
During this phase transition, the water molecules move out of the organized lattice and gain more freedom to move and slide past each other. This increased freedom allows the molecules to occupy a larger volume and have a more random arrangement, leading to an increase in potential energy.
Therefore, as ice melts and becomes liquid water, the potential energy of the water molecules increases due to the transition from a highly ordered lattice structure to a more disordered arrangement.