Question

A sealed glass jar is full of water. When its temperature is decreased to 0° C

• A. The glass jar remains as it is with ice
• B. The glass jar remains as it is with water
• C. Glass jar contains half the amount of ice mixed with water
• D. The glass jar breaks due to the formation of ice

Hint:

The anomalous expansion of water upon freezing is a fundamental concept with many real-world consequences, such as pipes bursting in winter, the weathering of rocks, and the fact that ice floats on water, which is crucial for aquatic life in cold climates.

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
We are asked to predict the outcome when a sealed jar completely filled with water is cooled to its freezing point.

Step 2: Key Formula or Approach:
The solution relies on the physical property of water known as anomalous expansion. Unlike most substances, water expands when it freezes into ice.

Step 3: Detailed Explanation:
Water exhibits a unique behavior regarding its density and temperature. Most substances contract upon cooling and solidifying. However, water contracts as it cools from higher temperatures down to 4°C, where it reaches its maximum density. As it cools further from 4°C to 0°C, it begins to expand slightly.
The most significant change occurs during the phase transition from liquid water to solid ice at 0°C. During freezing, the water molecules arrange themselves into a crystalline lattice structure (hexagonal) which is less dense than liquid water. This results in a significant increase in volume, approximately by 9%.
Since the glass jar is sealed and completely full of water, there is no empty space to accommodate this expansion. The expanding ice exerts an immense pressure on the inner walls of the glass jar. This pressure, known as frost wedging or cryostatic pressure, is strong enough to overcome the tensile strength of the glass, causing the jar to crack and break.

Step 4: Final Answer:
The glass jar breaks due to the formation of ice.