Explain the statement: the saturation vapour pressure of water at 60 degree Celsius is 149.4 mm of Mercury. Thanks

What is meant by the saturated vapour pressure if water at 60°C is 149.4mmHg

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Well, imagine 149.4 tiny little mercury bottles floating around at 60 degrees Celsius. They're just having a mercurial party up in there! But seriously, the saturation vapor pressure of water at 60 degrees Celsius means that the air is holding as much water vapor as it can at that temperature. It's like the air is saying, "No more, I'm full! I can't take any more water vapor in here!" It's pretty fascinating stuff.

Sure!

The saturation vapor pressure of water is a measure of the maximum amount of water vapor that can be held in the air at a particular temperature. At higher temperatures, more water molecules have enough energy to break free from the liquid and enter the vapor phase, increasing the vapor pressure.

In this case, the statement says that at a temperature of 60 degrees Celsius, the saturation vapor pressure of water is 149.4 mm of Mercury. This means that in an environment at 60 degrees Celsius, the air can hold a maximum of 149.4 mm Hg (millimeters of Mercury) of water vapor.

To put it simply, if the vapor pressure in the air reaches 149.4 mm Hg, the air is saturated with water vapor at that temperature. Any additional moisture will result in condensation, such as dew or fog.

The statement "the saturation vapour pressure of water at 60 degrees Celsius is 149.4 mm of Mercury" refers to a specific property of water vapor. Saturation vapor pressure is the pressure exerted by water vapor in a saturated air mixture at a given temperature. In this case, the given temperature is 60 degrees Celsius.

To understand how this value is determined, we need to explain a concept called the Clausius-Clapeyron equation. This equation describes the relationship between the vapor pressure of a substance and its temperature.

The Clausius-Clapeyron equation states that the logarithm of the saturation vapor pressure of a substance is directly proportional to its inverse temperature. Mathematically, the equation is expressed as:

ln(P2/P1) = -ΔHvap/R * (1/T2 - 1/T1)

In this equation:
- P1 and P2 are the vapor pressures at temperatures T1 and T2, respectively.
- ΔHvap is the enthalpy of vaporization, which represents the energy required to convert a substance from its liquid phase to its gas phase.
- R is the ideal gas constant.
- T1 and T2 are the temperatures at which the vapor pressures are measured, expressed in Kelvin.

By applying this equation to water vapor, we can determine the saturation vapor pressure at a given temperature. The reference temperature usually used for the saturation vapor pressure of water is 0 degrees Celsius.

To find the saturation vapor pressure of water at 60 degrees Celsius, we need to know the saturation vapor pressure at 0 degrees Celsius. The saturation vapor pressure of water at 0 degrees Celsius is approximately 4.6 mm of Mercury.

Using the Clausius-Clapeyron equation, we can calculate the saturation vapor pressure of water at 60 degrees Celsius as follows:

ln(P2/4.6) = (-ΔHvap/R) * (1/333 - 1/273)

To solve this equation, we need to know the enthalpy of vaporization (ΔHvap) for water. The enthalpy of vaporization of water is approximately 40.7 kJ/mol.

After substituting all the known values into the equation, we can solve for P2, which represents the saturation vapor pressure of water at 60 degrees Celsius. By calculating the expression, we find that P2 is approximately 149.4 mm of Mercury.

Therefore, the statement "the saturation vapor pressure of water at 60 degrees Celsius is 149.4 mm of Mercury" is derived using the Clausius-Clapeyron equation and known values for water vapor properties.