Question

a beaker of boiling water stops boiling and eventually reaches room temperature. there is no lid on the beaker. the beaker and its content must have:

a. gained thermal energy and mass from the surroundings.

b. gained thermal energy from the surroundings, but lost mass to the surroundings.

c. lost thermal energy and mass to the surroundings.

d. gained mass from the surroundings, but lost thermal energy to the surroundings.

Explanation:

1. Thermal Energy Analysis: Boiling water has a high temperature (100°C at standard pressure) and room temperature is lower. Heat flows from higher - temperature objects to lower - temperature objects. So the beaker and its contents (water) will lose thermal energy to the surroundings as they cool down to room temperature.
2. Mass Analysis: Since the beaker has no lid, the water is boiling (and even as it cools, there is still evaporation). Evaporation is the process where liquid water turns into water vapor and escapes into the air. So the mass of the water (and thus the beaker - water system) will decrease as water vapor is lost to the surroundings.

Now let's analyze each option:

• Option A: The system loses thermal energy (not gains) and loses mass (not gains), so A is incorrect.
• Option B: The system loses thermal energy (not gains), so B is incorrect.
• Option C: The system loses thermal energy (because it cools down) and loses mass (because of evaporation), so C is correct.
• Option D: The system loses mass (not gains) and loses thermal energy, so D is incorrect.

Answer:

C. lost thermal energy and mass to the surroundings.