Distinguish, with reference to molecular motion and energy, between solid ice and liquid water.

1. Molecular Motion: In solid ice, the molecules are tightly packed together in a fixed, regular pattern and can only vibrate in place. This is due to the strong hydrogen bonds that hold the water molecules together. The motion is minimal and restricted to vibrations. On the other hand, in liquid water, the molecules have more freedom to move around. They are still close together but can slide past each other, which allows the liquid to flow.

2. Energy: The molecules in solid ice have less energy than those in liquid water. This is because energy is required to break the hydrogen bonds holding the ice molecules together. When ice absorbs enough heat energy, the increased energy causes the molecules to move faster and the hydrogen bonds are broken, leading to a phase change from solid to liquid. Therefore, liquid water has more energy than solid ice as it has absorbed the energy needed to break the bonds that were holding the water molecules in a solid structure.

In summary, the main differences between solid ice and liquid water in terms of molecular motion and energy are that ice has a rigid structure with minimal molecular motion and lower energy, while water has more molecular motion and higher energy.