explain why the potential energy increases when ice starts to melt and becomes liquid water.

Answer 1

When ice starts to melt and become liquid water, the potential energy increases due to the change in the molecular structure. The increase in potential energy is a result of the breaking of intermolecular forces holding the ice lattice structure together.

In the solid state, the water molecules in ice are arranged in a regular and highly ordered lattice, held together by strong hydrogen bonds between the oxygen atom of one water molecule and the hydrogen atom of another. This organized arrangement gives ice its fixed shape and a relatively low potential energy.

However, when heat is applied to ice, the added energy breaks the hydrogen bonds between water molecules, allowing them to move more freely. As the temperature increases, the kinetic energy of the water molecules also increases, causing them to vibrate and move more energetically.

During the process of melting, the movements of the water molecules become more disordered, and the arrangement transitions from the fixed lattice structure of ice to the more random arrangement of liquid water. This transition from a highly ordered to a more disordered state increases the potential energy of the water.

Therefore, as ice melts and becomes liquid water, the potential energy increases because the hydrogen bonds are broken and replaced with weaker intermolecular forces that characterize the liquid state.