Calculate the vapor pressure of a substance using the Antoine Equation.
Temperature Measurement
°C
Antoine Constants
Vapor Pressure Results
Enter parameters to see results
About this calculator
Overview
Vapor pressure is the pressure exerts by a vapor when it is in thermodynamic equilibrium with its liquid or solid phase in a closed system. It is a critical indicator of a liquid's evaporation rate and its boiling point.
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Pro Tips
The Antoine constants are temperature-dependent. Ensure your temperature (T) is within the valid range for the constants used.
Most literature values for temperature are in Celsius (°C) and pressure in mmHg or kPa.
Water's standard constants (8.07131, 1730.63, 233.426) are valid between 1°C and 100°C.
Vapor pressure is independent of the amount of liquid or the surface area; it only depends on the subtsance and temperature.
At the boiling point, vapor pressure equals atmospheric pressure (760 mmHg at sea level).
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Fun Facts
"Vapor pressure explains why water boils at only 71°C at the top of Mt. Everest, making it hard to cook a proper egg!"
"Freeze-drying works by lowering the pressure below the substance's triple point, allowing ice to sublime directly into vapor."
"The 'smell' of a substance is directly related to its vapor pressure - high vapor pressure means more molecules reach your nose."
"Perfumes are formulated with 'top notes' (high vapor pressure) that you smell first, and 'base notes' (low vapor pressure) that last all day."
"Gasoline is a mixture of many compounds, each with its own vapor pressure, which is why it evaporates so differently at different temperatures."
