Askiitians Tutor Team
Last Activity: 14 Days ago
To understand what happens when water at 0°C is placed in a large evacuated chamber, we need to consider the properties of water and the concept of phase changes. Let’s break this down step by step.
The Basics of Water's Phase Changes
Water can exist in three states: solid (ice), liquid (water), and gas (water vapor). The transition between these states is influenced by temperature and pressure. At 0°C, water is at its freezing point, meaning it can exist as both ice and liquid water.
Understanding the Evacuated Chamber
An evacuated chamber is a space from which air and other gases have been removed. This creates a low-pressure environment. When you place water in such a chamber, the pressure above the water is significantly reduced. This is crucial because the boiling point of water decreases as pressure decreases.
What Happens to Water at 0°C in Low Pressure?
In a normal atmospheric environment, water at 0°C can exist as ice or liquid. However, when you lower the pressure significantly, the conditions change:
- Vaporization: At lower pressures, the energy required for water molecules to escape into the gas phase decreases. This means that some of the liquid water can start to vaporize even at 0°C.
- Freezing: Conversely, if the temperature remains at 0°C, some of the water can also freeze, especially if the conditions favor the solid phase.
Analyzing the Options
Now, let’s look at the options provided in your question:
- a. All the water will vaporize: This is unlikely because while some water will vaporize, not all of it will, especially since some can freeze.
- b. All the water will freeze: This is also not correct. The low pressure allows for vaporization, so not all water will turn to ice.
- c. Part of the water will vaporize and the rest will freeze: This is a strong possibility. The low pressure allows some water to vaporize while some remains as ice.
- d. Ice, water, and water vapor will be formed and reach equilibrium at the triple point: This is the most accurate option. The triple point of water occurs at a specific temperature and pressure where all three phases coexist in equilibrium. In a low-pressure environment at 0°C, it’s possible to reach this state.
Conclusion on the Mechanism
In summary, when water at 0°C is placed in a large evacuated chamber, the low pressure allows for both vaporization and freezing to occur simultaneously. Eventually, the system can reach a state where ice, liquid water, and water vapor coexist, which aligns with the conditions of the triple point. Therefore, the correct answer is option d.
This scenario beautifully illustrates the interplay between temperature and pressure in determining the state of matter. Understanding these concepts can help you grasp not only the behavior of water but also the principles governing other substances in different conditions.
