In the context of phase diagrams, what is most likely to occur if enough energy is absorbed by liquid water at atmospheric pressure?

• A. The water will remain as a liquid but increase in density.
• B. The water will decompose into hydrogen and oxygen gases.
• C. The water will undergo a phase transition to water vapor (gas).
• D. The water will freeze and become solid ice.

Answer: (C)

Verified step by step guidance

1. Understand that a phase diagram shows the states of a substance (solid, liquid, gas) at different temperatures and pressures.
2. Recognize that at atmospheric pressure, increasing the energy (heat) absorbed by liquid water raises its temperature until it reaches the boiling point.
3. At the boiling point, the water undergoes a phase transition from liquid to gas (water vapor) without a temperature increase during the transition.
4. Note that water does not increase in density when heated; instead, it expands and eventually vaporizes.
5. Also, water does not decompose into hydrogen and oxygen gases under normal heating conditions, nor does it freeze when energy is absorbed.