Which substance changes from a liquid to a vapor?

The transition from a liquid to a vapor refers to the process of evaporation or boiling, where a substance's molecules gain enough energy to break free from the liquid state and enter the gaseous state. Among the options provided, water is a common substance that undergoes this phase change.

When water heats up, its molecules move more rapidly; as they gain energy, they can overcome the intermolecular forces that keep them in the liquid state. At a certain temperature, typically 100 degrees Celsius at sea level, water transitions into steam, which is the vapor form of water. This makes it clear that water is the substance being referred to here that readily changes from a liquid to a vapor under standard conditions.

Ice, on the other hand, represents the solid state of water and transitions to liquid when heated, not directly to vapor. Steam is actually the vapor phase of water, so it does not undergo a change from liquid to vapor itself; it's already in the vapor state. Alcohol, while it can also change from liquid to vapor, is not the primary focus of the question in relation to the most common and easily recognizable phase change from a liquid to vapor in everyday contexts. Therefore, water is correctly identified as the answer to the question posed.