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wave525
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assuming water at atmospheric conditions, now if the pressure is reduced, at some lower point of pressure, water starts to boil.at this point, will the temp of water change and why?
wave525 said:assuming water at atmospheric conditions, now if the pressure is reduced, at some lower point of pressure, water starts to boil.at this point, will the temp of water change and why?
In Denver, Colorado, USA (1700 m above sea level), the boiling point of water is around 95 degrees Celsius (203 degrees Fahrenheit). At the top of Mt. Everest (9500 m above sea level), water boils at 75 degrees Celsius (167 degrees Fahrenheit).
If no heat is exchanged with the environment in other ways, the boiling will cool the water.wave525 said:will the temp of water change and why?
I am not sure what you mean.wave525 said:yes but the same energy is given by lowering the pressure, lowering the pressure is same as increasing the temperature of the water to boiling point, and if temp of water decreases due to lowering of pressure then temp of water should also drop on increasing temperature at atmospheric pressure.but this doesn't seem to happen.
I don't understand what you mean there, sorry. If you increase the temperature, the temperature should decrease?wave525 said:yes but the same energy is given by lowering the pressure, lowering the pressure is same as increasing the temperature of the water to boiling point, and if temp of water decreases due to lowering of pressure then temp of water should also drop on increasing temperature at atmospheric pressure.but this doesn't seem to happen.
mfb said:I don't understand what you mean there, sorry. If you increase the temperature, the temperature should decrease?
The boiling itself (molecules leaving the liquid) needs energy, this is independent of expansion/compression/heating of gases or liquids.
This happens at all pressures, unless you constantly add heat.wave525 said:∴, since you said boiling below atmospheric pressure causes decrease of water temperature
The melting point of water is dependent on the pressure exerted on it. At standard atmospheric pressure (1 atm), the melting point of water is 0°C or 32°F. However, as pressure increases, the melting point also increases. At a pressure of 10 atm, the melting point of water is approximately 10°C or 50°F.
The molecules of water are held together by hydrogen bonds. When pressure is applied, these bonds are compressed, making it more difficult for the molecules to break free and transition into a liquid state. This results in a higher melting point as the pressure increases.
Yes, water can have a melting point below 0°C if the pressure is low enough. This is known as supercooling, where water remains in a liquid state at temperatures well below its freezing point. However, this is not a stable state and any disturbance or addition of impurities can cause the water to freeze instantly.
Similar to the melting point, pressure also affects the boiling point of water. At standard atmospheric pressure, water boils at 100°C or 212°F. However, at high pressures, such as in a pressure cooker, the boiling point of water can increase significantly, allowing for faster cooking times.
Understanding the pressure effects on the melting point of water is crucial in many scientific and industrial processes. For example, in the production of ice cream, the correct pressure must be maintained in order to create a smooth and creamy texture. In addition, the study of pressure effects on water can also help us understand the behavior of other substances under different pressures.