How To Calculate Vapor Pressure Given Temperature And Pressure

Vapor Pressure Equation:

\[ e = e_s(T) \times \left( \frac{RH}{100} \right) \]

Vapor Pressure (e):

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1. What is Vapor Pressure?

Vapor pressure is the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases at a given temperature. It's a crucial parameter in meteorology, chemistry, and various engineering applications.

2. How Does the Calculator Work?

The calculator uses the vapor pressure equation:

\[ e = e_s(T) \times \left( \frac{RH}{100} \right) \]

Where:

\( e \) — Vapor pressure (Pa)
\( e_s \) — Saturation vapor pressure at temperature T (Pa)
\( RH \) — Relative humidity (%)

Explanation: This equation calculates the actual vapor pressure from the saturation vapor pressure and relative humidity. The saturation vapor pressure depends on temperature and can be calculated using various empirical formulas.

3. Importance of Vapor Pressure Calculation

Details: Vapor pressure calculations are essential for weather forecasting, humidity control systems, industrial processes, and understanding various atmospheric phenomena. Accurate vapor pressure measurements help predict condensation, evaporation rates, and comfort levels in environmental systems.

4. Using the Calculator

Tips: Enter saturation vapor pressure in Pascals (Pa) and relative humidity as a percentage (0-100%). Both values must be valid positive numbers with RH between 0-100%.

5. Frequently Asked Questions (FAQ)

Q1: What is saturation vapor pressure?
A: Saturation vapor pressure is the maximum vapor pressure that can exist at a given temperature, when the air is saturated with water vapor.

Q2: How does temperature affect vapor pressure?
A: Vapor pressure increases exponentially with temperature. Warmer air can hold more water vapor than cooler air.

Q3: What units are used for vapor pressure?
A: Vapor pressure is typically measured in Pascals (Pa) or millibars (mb), with 1 mb = 100 Pa.

Q4: How is relative humidity related to vapor pressure?
A: Relative humidity is the ratio of actual vapor pressure to saturation vapor pressure, expressed as a percentage.

Q5: Why is vapor pressure important in meteorology?
A: Vapor pressure helps determine dew point, predict fog formation, and understand various weather patterns and atmospheric stability.