Calculate vapor pressure from temperature with the Antoine equation, or temperature from pressure, using built-in water and solvent constants or your own.
Pressure From Antoine Equation Formula
The following example problem outlines the steps and information needed to calculate the Pressure From the Antoine equation.
Variables:
- P is the saturation vapor pressure. Custom constants in this calculator must use log10(P/mmHg) = A − B/(T/°C + C); do not enter bar/K constants unchanged.
- A, B, and C are Antoine constants for a given substance (they depend on the pressure and temperature units used); T is the temperature (typically in °C for this form).
How to Calculate Pressure From Antoine Equation?
The following steps outline how to calculate the Pressure From the Antoine equation.
- Choose a preset or enter custom Antoine constants A, B, C and their valid temperature range. The water preset covers 1–100 °C; ethanol −57–80 °C; benzene 14.55–80.92 °C; methanol 15–84 °C; acetone −13–55 °C; toluene 6–137 °C. The benzene set is converted from the NIST Chemistry WebBook bar/K fit. Stay within the fitted range; this pure-component correlation does not describe mixtures.
- Next, gather the formula from above = P = 10 (A- (B/(C+T))).
- Finally, calculate the Pressure From the Antoine equation.
- After inserting the variables and calculating the result, check your answer with the calculator above.
Example Problem :
Use the following variables as an example problem to test your knowledge.
A = 8, B = 1708, C = 233, and T = 99 °C
P = 10(8 − 1708/(233 + 99)) ≈ 716.8391 mmHg ≈ 95.5707 kPa. Select Custom and enter these constants with temperature 99 °C. This is an algebraic example with no supplied substance or fit range; it does not establish physical validity. For the inverse calculation use T = B/[A − log10(P/mmHg)] − C.
