If you are using proper browser, you can calculate properties with JOBACK method. This program calculate, boiling point, Critical temperature. Property Estimation Joback Method spreadsheet calculates thermophysical and transport properties as a function of the sum of group parameters. Some of the. The Joback method is a group contribution method. These kind of methods use basic structural information of a chemical molecule like a list of simple functional .

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The molar heat capacity is the capacity per unit amount of a pure substance. Some of the most basic properties needing to be estimated for pure ,ethod are the molecular weight, the melting point and the normal boiling point.

Joback method

Newer developments of estimation methods [3] [4] have shown that the quality of the Joback method is limited. The horizontal axis is the temperature divided by the Debye temperature.

In other words, an alkane consists of hydrogen and carbon atoms arranged in a structure in meghod all the carbon-carbon bonds are single. The magnitude F of this force is found to be proportional to the u and the area A of each plate.

The remaining properties are obtained from previously estimated values. These parameters are valid from K to approx. For simplicity and clarity, the notion of critical point is best introduced by discussing a specific example.

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How to use Joback Properties estimation method, HTML5 program

For example, the molecular structure of 1-butanol is shown in Figure 1. A sample containing twice the amount of substance as another sample requires the transfer of twice the amount of heat to achieve the change in temperature. In such cases, the capacity is a fraction of the maximum.

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It can be produced by decomposition of only certain compounds. Group contribution estimation techniques begin with a compound’s molecular structure. They can be viewed as molecular trees upon which can be hung the more functional groups of biological molecules.

The existence of a point was first discovered by Charles Cagniard de la Tour in and named by Dmitri Mendeleev in The liquid—liquid critical point of a solution, which occurs at the solution temperature 4. Joback assumed a constant contribution of added groups in homologous series like the alkanes. The Joback method additionally uses a very simple and easy to assign group scheme, which makes the method usable also for people with only basic chemical knowledge.

In the following formulas G i denotes a group contribution. The critical temperature, critical pressure and critical volume are required inputs.

Such work brings together all available past and current data, as a basis to develop reasonable expectations about the future, in statistics, prediction is a part of statistical inference. This page was last edited on 11 Octoberat Hoback that, as expected, the dimensionless heat capacity is zero at absolute zero, and rises to a value of three as the temperature becomes much larger than the Debye temperature.


This webpage provides descriptions and calculation capabilities for a number of commonly used physical properties.

Joback method – WikiVisually

Zero viscosity is observed only at low temperatures in superfluids. Methyl group — A methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms — CH3. The critical volume is estimated by Joback’s method [1], a group contribution technique. Retrieved from ” https: A prediction of this kind might be valid if the predictor is a knowledgeable person in the field and is employing sound reasoning. The list of groups don’t cover many common molecules sufficiently.

A term and a polynomial with no indeterminates are called, respectively, a constant term, the degree of a constant term and of a nonzero constant polynomial is 0.

Group Dissection of 1-Butanol. Joback assumes that there are no interactions between the groups and therefore only uses additive contributions and no contributions for interactions between groups. The popularity and success of the Joback method mainly originates from the single group list for all properties.