Created By : Rina Nayak

Reviewed By : Phani Ponnapalli

Last Updated : May 12, 2023

Take advantage of this free online Langmuir Isotherm Calculator tool that helps you to calculate the fraction or percent of the absorbent surface covered by an absorbate. Simply, give the inputs in the input fields and click the calculate button that gives you the answer immediately in seconds.

equilibrium constant (Keq)
Partial pressure(P)

What is Langmuir Isotherm?

Here we are going to know some basic definitions before going to know about Langmuir Isotherm :

Absorption: It is a process of adhesion that connects molecules, atoms, or ions to a surface (or a phase boundary). During this process, absorbate creates a thin layer on the surface of the absorbent.

Chemisorbtion: It is also a type of adsorption that creates a strong chemical bonds between the absorbate and absorbent.

Isotherm: It is a function that describes the change in the amount of adhered substance, depending on the substances partial pressure or concentration, reaction takes place in isothermal conditions.

Now coming to Languir isotherm, it is based on three assumptions. They are given below.

1. The absorbate particles behaves as an ideal gas.

2. These absorbate particles cannot create multi layers.

3. The energy of the substance is identical and flat in all places.

Now, let us look into the formula for languir isotherm.

θ = (Keq * P) / (1 + (Keq * P))


θ is the fraction of surface covered by absorbate.

Keq is  adsorbtion equilibrium constant.

P is partal gas pressure

In order to receive percentage of the surface covered by absorbate then

θpercent = θfraction * 100

How do you Calculate Langmuirs Isotherm?

We will look into the below steps that are explained in detail on how to calculate Langmuris Isotherm.

  • Firstly, write down the details that are given in the problem.
  • Then, apply the Langmuirs Isotherm formula, i.e., θ = (Keq * P) / (1 + (Keq * P))
  • Substitue the values in it and apply the formula.
  • Finally, you will get the answer.

To know more about similar kind of calculators you can check out our portal and use them for instant answers.

FAQs on Langmuirs Isotherm Calculator

1. What is Langmuir Formula?

Langmuir Isotherm Formula,

θ = (Keq * P) / (1 + (Keq * P))

2. What is the unit of Langmuir Constant?

In this langmuir constant adsorption, the unit of langmuir constant is M-1 ( or L mol-1).

3. What affects adsorption rate?

When the pressure has increased the rate of adsorption also increases, due to an increase in the gas molecules striking on the surface.

4. What are the steps to use langmuirs theorem Calculator?

  • Initially, give the specific inputs in the input field.
  • Then, click on the calculate button.
  • Finally, get the answer in seconds.