What is the surface tension of water at 0 degrees?

Chemistry
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What is the surface tension of water at 0 degrees?

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What is the surface tension of water at 0 degrees?

Answer:

The surface tension of a liquid is a measure of the cohesive forces at the surface that allows the surface to resist an external force. It is an important property in many scientific and practical applications, such as in the formation of droplets, capillary action, and the behavior of bubbles.

Surface Tension of Water at 0°C:

At 0 degrees Celsius, the surface tension of water is approximately 75.6 mN/m (milliNewtons per meter). This value is obtained under standard atmospheric pressure and reflects the cohesive forces between water molecules, primarily due to hydrogen bonding.

To understand this value, let’s explore why surface tension is significant and how it can vary:

Key Concepts:

  1. Cohesion and Hydrogen Bonding:

    • Water molecules are polar, having a slightly positive charge on the hydrogen atoms and a slightly negative charge on the oxygen atom.
    • This polarity leads to hydrogen bonding, where the positive region of one water molecule is attracted to the negative region of another.
    • At the surface, molecules experience a net inward force due to hydrogen bonds, increasing surface tension.

  2. Temperature Influence:

    • Temperature affects surface tension; as temperature increases, kinetic energy overcomes cohesive forces, reducing surface tension.
    • Conversely, lower temperatures like 0°C tend to increase surface tension since molecular motion is reduced, allowing stronger cohesive forces between molecules. This explains the relatively high value of 75.6 mN/m.

  3. Measurement Techniques:

    • Surface tension can be measured using methods such as the capillary rise method, du Noüy ring method, and Wilhelmy plate method.
    • These techniques often exploit the curvature of the liquid surface and the adhesive properties between the liquid and a solid material to quantify surface tension.

Applications and Implications:

  • Biological Systems: Surface tension is crucial for processes like respiration in the lungs, where surfactants reduce surface tension to prevent alveolar collapse.
  • Industrial Processes: Knowledge of surface tension is important in industries for designing products such as detergents and coatings, where altering surface tension is necessary.
  • Environmental Science: Capillary action, driven by surface tension, is vital for soil moisture retention and plant water uptake.

Graphical Representation:

To visually support this information, consider a graph of surface tension against temperature for water:

Surface Tension (mN/m)
|
|                 .. (Value of 75.6 mN/m at 0°C)
|                / \
|               /   \
|              /     \ 
|              .....
|_________________________________
      Temperature (°C)
   -10      0       10      20

Summary:

The surface tension of water at 0 degrees Celsius is 75.6 mN/m, reflecting the strong cohesive forces due to hydrogen bonding. This property is essential for many natural and artificial phenomena influenced by water’s interaction with its environment.

In conclusion, the surface tension of water at cold temperatures exemplifies the significant role that molecular interactions play in determining physical properties.

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