Final answer:
Water and rock undergo phase changes when melting, with water's composition remaining constant but rock potentially having partial melting due to mineral composition variations. Both substances transition from solid to liquid, with water melting at 0°C and rock melting at various higher temperatures, influenced by pressure, temperature, and the presence of water.
Step-by-step explanation:
To compare and contrast the melting of water and rock, we must understand the physical changes that occur for each substance. The melting of water is a uniform physical change where the composition remains constant (℃) - 11.19% hydrogen and 88.81% oxygen by mass. In contrast, the melting of rock can involve partial melting due to variations in mineral composition and the conditions of temperature and pressure. Both processes involve a phase change from solid to liquid, where energy is added to the system causing the molecules to overcome the attractive forces holding them in a solid structure.
Statement A (Melting of Water): The composition of water stays the same during melting as it does in its frozen state, which is simply a physical change.
Statement B (Melting of Rock): Rocks can undergo partial melting, where different minerals may melt at different temperatures, often influenced by the presence of water and changes in pressure, leading to a mixture of solid and liquid phases.
Statement C (Applies to Both): Both water and rock undergo a phase change when they melt, transitioning from a solid to a liquid state.
Statement D (Applies to Neither): The melting point of water is 0°C, not 100°C, which is the boiling point of water. The melting point for rock varies widely depending on its composition and can occur at much higher temperatures.