Vapor Pressure Calculator

Introducing our Vapor Pressure Calculator: Your go-to tool for swiftly determining the vapor pressure of substances at different temperatures, simplifying complex vaporization analyses with ease.





On this page:

Unlocking the Mysteries of Vapor Pressure: Your Ultimate Vapor Pressure Calculator Guide

Are you inquisitive about the complexities of vapor pressure? Do you locate yourself misplaced in a cloud of confusion while trying to calculate it? Fear no longer, for we're here to shed mild on this fascinating phenomenon and offer you a complete vapor pressure calculator guide. In this text, we can delve into the basics of vapor pressure, discover its importance in diverse industries, and equip you with the tools to results easily calculate it. So, sit returned, loosen up, and let's embark on a journey through the sector of vapor pressure collectively.

Understanding Vapor Pressure

Before we dive into the intricacies of vapor pressure calculation, let's first grasp the concept itself. Vapor stress is described as the pressure exerted by means of a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in a closed machine. In less difficult phrases, it is the measure of a substance's tendency to evaporate right into a gasoline phase. This phenomenon performs a pivotal function in several medical disciplines, along with chemistry, physics, and meteorology.

Vapor Pressure Calculator Formula

The formula to calculate vapor pressure ($P$) is:

\[ P = P_0 \times e^{\frac{-\Delta H_{\text{vap}}}{RT}} \]


  • \( P \) = Vapor pressure
  • \( P_0 \) = Vapor pressure constant
  • \( \Delta H_{\text{vap}} \) = Enthalpy of vaporization
  • \( R \) = Gas constant
  • \( T \) = Temperature in Kelvin

This formula is derived from the Clausius-Clapeyron equation and is used to determine the pressure exerted by a substance's vapor at a specific temperature. It takes into account the vapor pressure constant, enthalpy of vaporization, gas constant, and temperature to calculate the vapor pressure.

Vapor Pressure Calculation Examples

Example 1

Calculate the vapor pressure (\( P \)) of a substance at a temperature of \( 300 \, \text{K} \), given:

  • Vapor pressure constant (\( P_0 \)): \( 10 \, \text{mmHg} \)
  • Enthalpy of vaporization (\( \Delta H_{\text{vap}} \)): \( 40 \, \text{kJ/mol} \)
  • Gas constant (\( R \)): \( 8.314 \, \text{J/(mol} \cdot \text{K)} \)

\[ P = 10 \times e^{\frac{-40}{8.314 \times 300}} \]

Example 2

Calculate the vapor pressure (\( P \)) of a substance at a temperature of \( 350 \, \text{K} \), given:

  • Vapor pressure constant (\( P_0 \)): \( 15 \, \text{mmHg} \)
  • Enthalpy of vaporization (\( \Delta H_{\text{vap}} \)): \( 50 \, \text{kJ/mol} \)
  • Gas constant (\( R \)): \( 8.314 \, \text{J/(mol} \cdot \text{K)} \)

\[ P = 15 \times e^{\frac{-50}{8.314 \times 350}} \]

Example 3

Calculate the vapor pressure (\( P \)) of a substance at a temperature of \( 400 \, \text{K} \), given:

  • Vapor pressure constant (\( P_0 \)): \( 20 \, \text{mmHg} \)
  • Enthalpy of vaporization (\( \Delta H_{\text{vap}} \)): \( 60 \, \text{kJ/mol} \)
  • Gas constant (\( R \)): \( 8.314 \, \text{J/(mol} \cdot \text{K)} \)

\[ P = 20 \times e^{\frac{-60}{8.314 \times 400}} \]

Example 4

Calculate the vapor pressure (\( P \)) of a substance at a temperature of \( 450 \, \text{K} \), given:

  • Vapor pressure constant (\( P_0 \)): \( 25 \, \text{mmHg} \)
  • Enthalpy of vaporization (\( \Delta H_{\text{vap}} \)): \( 70 \, \text{kJ/mol} \)
  • Gas constant (\( R \)): \( 8.314 \, \text{J/(mol} \cdot \text{K)} \)

\[ P = 25 \times e^{\frac{-70}{8.314 \times 450}} \]

The Significance of Vapor Pressure

Vapor pressure isn't always merely a theoretical concept restricted to laboratory experiments; it holds colossal sensible significance in various actual-world applications. For instance, in the area of chemistry, vapor pressure is important for expertise segment transitions, which include boiling and evaporation. Moreover, it influences the conduct of unstable substances in closed-packing containers and plays a crucial role in determining their storage situations.

In the world of meteorology, vapor pressure plays a pivotal role in the formation of clouds, precipitation, and climate styles. By monitoring adjustments in vapor pressure, meteorologists can make more accurate predictions approximately atmospheric conditions, thereby improving our capacity to forecast weather events.

Calculating Vapor Pressure: A Step-by means of-Step Guide

Now that we've laid the basis, let's delve into the nitty-gritty of vaporpressure calculation. While the arithmetic at the back of it can appear daunting at first glance, fear now not, for we have simplified the process into easy-to-observe steps:

Step 1: Gather the Necessary Data

Before you calculate vapor pressure, you will want to acquire a few important records:

Temperature: The temperature at which the substance is being measured.

Vapor Pressure Constant: This is particular to every substance and may be determined in reference tables or databases.

Molecular Weight: The molecular weight of the substance in question.

Step 2: Plug Into the Equation

Once you have accumulated the vital information, you may plug it into the subsequent equation to calculate vapor strain:

Step 3: Crunch the Numbers

With all the variables in place, it's time to crunch the numbers and calculate the vapor pressure of the substance at the given temperature. Be certain to double-test your calculations to ensure accuracy.

Common Substances

In the following table, we have mentioned various compounds, their boiling point, normal temperature, and heat of vaporization.

Compound Boiling point, at normal pressure Heat of vaporization
(K) (°C) (°F) (kJ/mol) (J/g)
Acetone 329 56 133 31.300 538.9
Aluminium 2792 2519 4566 294.0 10500
Ammonia 240 −33.34 −28 23.35 1371
Butane 272–274 −1 30–34 21.0 320
Diethyl ether 307.8 34.6 94.3 26.17 353.1
Ethanol 352 78.37 173 38.6 841
Hydrogen (parahydrogen) 20.271 −252.879 −423.182 0.8992 446.1
Iron 3134 2862 5182 340 6090
Isopropyl alcohol 356 82.6 181 44 732.2
Methane 112 −161 −259 8.170 480.6
Methanol 338 64.7 148 35.2 1104
Propane 231 −42 −44 15.7 356
Phosphine 185 −87.7 −126 14.6 429.4
Water 373.15 100 212 40.66 2257

Leveraging Technology: The Vapor Pressure Calculator

In the cutting-edge digital age, we are fortunate to have get right of entry to a plethora of gear and assets that simplify complex calculations. One such device is the vapor pressure calculator, a on-hand online tool that automates the process of vapor strain calculation. By simply inputting the applicable data, consisting of temperature and molecular weight, the calculator will unexpectedly generate the vapor pressure fee, saving you effort and time.


In the end, vapor stress is a fundamental concept with huge-ranging packages in technological know-how and industry. By information its standards and mastering the art of vapor pressure calculation, you may unencumber new insights into the conduct of materials and beautify your trouble-solving abilities. Whether you're a pupil, researcher, or industry professional, the know-how gained from this vapor pressure calculator manual will surely prove priceless to your endeavors. So, move forth and discover the charming international of vapor stress with self-belief and curiosity!

Frequently Asked Questions FAQ

What is vapor pressure?
Vapor stress is the stress exerted via the usage of a vapor in thermodynamic equilibrium with its condensed stages (solid or liquid) at a given temperature in a closed machine. In easier phrases, it's far the degree of a substance's tendency to evaporate right into a gasoline phase.
How is vapor strain calculated?
Vapor stress may be calculated using mathematical equations that contain elements which includes temperature, vapor pressure steady, enthalpy of vaporization, and fuel consistent. These calculations assist determine the pressure exerted by way of a substance's vapor at a selected temperatur
What elements affect vapor stress?
Several elements can have an effect on vapor stress, consisting of temperature, intermolecular forces, molecular weight, and surface region. Generally, an growth in temperature leads to higher vapor stress, whilst stronger intermolecular forces tend to lower it.
What are some real-international programs of vapor strain?
Vapor stress has severa real-world programs, including weather prediction, chemical synthesis, prescription drugs, and food processing. It is essential for expertise the conduct of substances in various environments and optimizing commercial techniques.
How can I use vapor pressure in normal existence?
While vapor pressure may additionally look like a complicated medical concept, its standards may be applied in ordinary lifestyles. For instance, know-how vapor strain will let you pick out appropriate cooking methods, expect weather patterns, and troubleshoot issues in chemical processes.
Is vapor stress suffering from altitude?
Yes, vapor strain is affected by altitude. As altitude will increase, atmospheric strain decreases, which can impact the boiling point of drinks and the rate of evaporation. This phenomenon is especially applicable in high-altitude regions in which cooking instances and atmospheric conditions vary from sea level.

Have Feedback or a Suggestion?

Kindy let us know your reveiws about this page