When liquid water is heated, which of the following occurs as it approaches thermal equilibrium with its surroundings?

• A. The water immediately turns into ice.
• B. The temperature of the water increases until it matches the temperature of the heat source.
• C. The temperature of the water remains constant regardless of the heat source.
• D. The temperature of the water decreases until it matches the temperature of the heat source.

Answer: (B)

Verified step by step guidance

1. Understand the concept of thermal equilibrium: it occurs when two objects or systems in contact no longer exchange heat because they have reached the same temperature.
2. Recognize that when liquid water is heated, heat energy is transferred to the water molecules, increasing their kinetic energy and thus raising the temperature of the water.
3. Recall that water will not immediately change phase (such as turning into ice) when heated; instead, its temperature changes first until it reaches the temperature of the heat source.
4. Apply the principle that the temperature of the water will continue to increase as long as heat is being added and until the water's temperature equals that of the heat source, achieving thermal equilibrium.
5. Conclude that the correct behavior is that the temperature of the water increases until it matches the temperature of the heat source, rather than remaining constant or decreasing.