Antoine Equation Calculator (Online & Free) For Chemical Engineers

Q: 2. What is the difference between the Clausius-Clapeyron and Antoine equations?

The Clausius-Clapeyron equation is a theoretical formula that shows how vapor pressure changes with temperature, using basic thermodynamic properties like the heat of vaporisation. While Antoine equation is empirical and based on experimental data. It’s used to accurately calculate vapor pressure for a specific substance over a limited temperature range, using constants.

Chemical Tweak presents Antoine Equation Calculator, which helps you quickly calculate vapour pressure or temperature. Using this free tool, you can find pressure at any temperature or solve for temperature at a given pressure, using a built-in chemical database or your own constants.

Antoine Equation Calculator for chemical engineers

Antoine's Equation Calculator

log₁₀(P / mmHg) = A − B / (C + T / °C)

Calculate vapor pressure and temperature relationships using the Antoine equation. All database constants are for P in mmHg and T in °C (NIST / Dortmund form). Choose from the chemical database or enter custom constants.

Input Parameters

Calculation Mode:

Select Chemical:

Pressure Unit:

Temperature Unit:

Temperature (°C):

Pressure (mmHg):

Results

Vapor Pressure: -

Temperature: -

log₁₀(P / mmHg): -

Unit Conversions: -

What is the Louis Charles Antoine equation?

The Louis Charles Antoine equation, more commonly known as the Antoine Equation, is an empirical formula used to estimate the vapor pressure of pure substances as a function of temperature. It’s widely used for calculations involving phase changes, such as boiling or condensation.

$\log_{10} P = A - \frac{B}{C + T}$

Where,
P is the vapor pressure.
T – Temperature (in degrees Celsius)
A, B & C – Antoine constants, specific to each chemical and valid only within a certain temperature range

The Antoine constants cited in this article are sourced from the NIST Chemistry WebBook (SRD 69). This database is maintained by the National Institute of Standards and Technology and provides peer-reviewed thermophysical properties for chemical compounds.

Looking for the Boiling Point? If you need to find the specific temperature at which a chemical boils under vacuum or high pressure, use our specialised Boiling Point Calculator, which provides temperature results in °C, °F, and K and for vapour pressure calculation, we have Clausius-Clapeyron calculator and various other chemical engineering tools

Frequently Asked Questions

1. What is the Antoine equation used for?

It is used to calculate the vapour pressure of a pure substance at different temperatures. It helps engineers and scientists predict when a liquid will start to boil or condense under various conditions. This is important in processes like distillation, evaporation, and chemical manufacturing, where knowing the vapor pressure is essential.

2. What is the difference between the Clausius-Clapeyron and Antoine equations?

The Clausius-Clapeyron equation is a theoretical formula that shows how vapor pressure changes with temperature, using basic thermodynamic properties like the heat of vaporisation. While Antoine equation is empirical and based on experimental data. It’s used to accurately calculate vapor pressure for a specific substance over a limited temperature range, using constants.

3. What are the Antoine Constants (A, B, and C)?

These are substance-specific coefficients derived from experimental data:
Constant A: Represents the overall volatility of the chemical.
Constant B: Correlates with the latent heat of vaporization.
Constant C: Acts as a temperature correction factor to ensure the equation fits real-world data across specific ranges.