# The Product Types Ontology: Class Definition for "Gas constant"

This page is part of http://www.productontology.org/, a huge, precise dictionary of product types and brand names for marking up Web sites with schema.org or the GoodRelations e-commerce standard.

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### pto:Gas_constant(rdf:type owl:Class)

URI http://www.productontology.org/id/Gas_constant
rdfs:subClassOf gr:ProductOrService, http://schema.org/Product
rdfs:label Gas constant (as a class or brand name of products of services)
Translation(s):  Gaskonstante@af;  ثابت الغازات العام@ar;  গেছ ধ্ৰুৱক@as;  Qaz sabiti@az;  Універсальная газавая пастаянная@be;  Универсална газова константа@bg;  গ্যাস ধ্রুবক@bn;  Univerzalna plinska konstanta@bs;  Constant dels gasos@ca;  Molární plynová konstanta@cs;

rdfs:comment

The molar gas constant (also known as the gas constant, universal gas constant, or ideal gas constant) is denoted by the symbol or . It is the molar equivalent to the Boltzmann constant, expressed in units of energy per temperature increment per amount of substance, i.e. the pressure–volume product, rather than energy per temperature increment per particle. The constant is also a combination of the constants from Boyle's law, Charles's law, Avogadro's law, and Gay-Lussac's law. It is a physical constant that is featured in many fundamental equations in the physical sciences, such as the ideal gas law, the Arrhenius equation, and the Nernst equation. The gas constant is the constant of proportionality that relates the energy scale in physics to the temperature scale and the scale used for amount of substance. Thus, the value of the gas constant ultimately derives from historical decisions and accidents in the setting of units of energy, temperature and amount of substance. The Boltzmann constant and the Avogadro constant were similarly determined, which separately relate energy to temperature and particle count to amount of substance. The gas constant R is defined as the Avogadro constant NA multiplied by the Boltzmann constant k (or kB): <math display="block">R = N_{\rm A} k. Since the 2019 redefinition of SI base units, both NA and k are defined with exact numerical values when expressed in SI units. As a consequence, the SI value of the molar gas constant is exactly . Some have suggested that it might be appropriate to name the symbol R the Regnault constant in honour of the French chemist Henri Victor Regnault, whose accurate experimental data were used to calculate the early value of the constant. However, the origin of the letter R to represent the constant is elusive. The universal gas constant was apparently introduced independently by Clausius’ student, A.F. Horstmann (1873) and Dmitri Mendeleev who reported it first on Sep. 12, 1874. Using his extensive measurements of the properties of gases, Mendeleev also calculated it with high precision, within 0.3% of its modern value. The gas constant occurs in the ideal gas law: <math display="block">PV = nRT = m R_{\rm specific} T where P is the absolute pressure, V is the volume of gas, n is the amount of substance, m is the mass, and T is the thermodynamic temperature. Rspecific is the mass-specific gas constant. The gas constant is expressed in the same unit as are molar entropy and molar heat. (Source: Wikipedia, the free encyclopedia, see http://en.wikipedia.org/wiki/Gas_constant)

Note: The extraction of the abstract from the Wikipedia page may sometimes yield imperfect results. We are improving the algorithm regularly.

Note: This is a generic list. Some of the properties may not be applicable to this particular type of object.

Trademark Disclaimer:  Since this service returns class descriptions for potentiall any series of characters, it cannot indicate automatically whether a name is a registered trademark or otherwise protected. We assume no liability for the absence of trademark rights and other damages. See the section "License" below for details.

## Usage

</div>
</div>
</body>
</html>


### Turtle Syntax

@prefix foaf: <http://xmlns.com/foaf/0.1/> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
@prefix pto: <http://www.productontology.org/id/> .
@prefix gr: <http://purl.org/goodrelations/v1#> .
@prefix foo: <http://example.com/> .

# The object
foo:myObject a <http://www.productontology.org/id/Gas_constant> ;
a gr:SomeItems ;
gr:name "... a short name for the object ..."@en ;
gr:description "... a longer description ..."@en .

# The agent (person or company) who is offering it
gr:legalName "ACME Corp" ;
gr:offers foo:Offer .

# The offer to sell it
foo:Offer a gr:Offering ;
gr:includes foo:myObject;
foaf:page <http://URI_of_the_page_containing_the_offer.com>;
gr:validFrom "2011-01-24T00:00:00+01:00"^^xsd:dateTime ;
gr:validThrough "2011-12-24T00:00:00+01:00"^^xsd:dateTime ;
gr:hasPriceSpecification
[ a gr:UnitPriceSpecification ;
gr:hasCurrency "USD"^^xsd:string ;
gr:hasCurrencyValue "19.99"^^xsd:float ;
gr:validThrough "2011-12-24T00:00:00+01:00"^^xsd:dateTime ] .


Note: Replace gr:SomeItems (http://purl.org/goodrelations/v1#SomeItems) by gr:Individual if you are describing a unique object of that kind (e.g. antique furniture).

### RDFa

<!DOCTYPE html>
<html version="HTML+RDFa 1.1" xmlns="http://www.w3.org/1999/xhtml">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
<title>An offer to sell a / some Gas_constant</title>
<body>
<div xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
xmlns:foaf="http://xmlns.com/foaf/0.1/"
xmlns:gr="http://purl.org/goodrelations/v1#"
xmlns:pto="http://www.productontology.org/id/"
xmlns:foo="http://example.com/"
xmlns:xsd="http://www.w3.org/2001/XMLSchema#">

<!-- The agent (person or company) who is offering it -->
<div property="gr:legalName">ACME Corp</div>
<div rel="gr:offers">
<!-- The offer to sell it -->
<div rel="gr:includes">
<!-- The object -->
<div rel="rdf:type" resource="http://purl.org/goodrelations/v1#SomeItems"></div>
<div property="gr:description" xml:lang="en">... a longer description ...</div>
<div property="gr:name" xml:lang="en">.. a short name for the object ...</div>
</div>
</div>
<div rel="foaf:page" resource="http://URI_of_the_page_containing_the_offer"></div>
<div rel="gr:hasPriceSpecification">
<div typeof="gr:UnitPriceSpecification">
<div property="gr:hasCurrency" content="USD" datatype="xsd:string">\$ </div>
<div property="gr:hasCurrencyValue" datatype="xsd:float">19.99</div>
<div property="gr:validThrough" content="2011-12-24T00:00:00+01:00"
datatype="xsd:dateTime"></div>
</div>
</div>
<div property="gr:validFrom" content="2011-01-24T00:00:00+01:00"
datatype="xsd:dateTime"></div>
<div property="gr:validThrough" content="2011-12-24T00:00:00+01:00"
datatype="xsd:dateTime"></div>
</div>
</div>
</div>
</div>
</body>
</html>


Note: Replace gr:SomeItems (http://purl.org/goodrelations/v1#SomeItems) by gr:Individual if you are describing a unique object of that kind (e.g. antique furniture).

### RDF/XML

<?xml version="1.0" encoding="UTF-8" ?>
<rdf:RDF xmlns:gr="http://purl.org/goodrelations/v1#"
xmlns:pto="http://www.productontology.org/id/"
xmlns:xsd="http://www.w3.org/2001/XMLSchema#"
xmlns:foaf="http://xmlns.com/foaf/0.1/"
xmlns:foo="http://example.com/"
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
<!-- The object -->
<rdf:type rdf:resource="http://www.productontology.org/id/Gas_constant"/>
<rdf:type rdf:resource="http://purl.org/goodrelations/v1#SomeItems"/>
<gr:name xml:lang="en">... a short name for the object ...</gr:name>
<gr:description xml:lang="en">... a longer description ...</gr:description>
</rdf:Description>
<!-- The agent (person or company) who is offering it -->
<gr:legalName>ACME Corp</gr:legalName>
<gr:offers rdf:resource="http://example.com/Offer" />
<!-- The offer to sell it -->
<gr:includes rdf:resource="http://example.com/myObject" />
<foaf:page rdf:resource="http://URI_of_the_page_containing_the_offer"/>
<gr:validFrom rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">
2011-01-24T00:00:00+01:00</gr:validFrom>
<gr:validThrough rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">
2011-12-24T00:00:00+01:00</gr:validThrough>
<gr:hasPriceSpecification>
<gr:UnitPriceSpecification>
<gr:hasCurrency rdf:datatype="http://www.w3.org/2001/XMLSchema#string">USD</gr:hasCurrency>
<gr:hasCurrencyValue rdf:datatype="http://www.w3.org/2001/XMLSchema#float">19.99</gr:hasCurrencyValue>
<gr:validThrough rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">
2011-12-24T00:00:00+01:00</gr:validThrough>
</gr:UnitPriceSpecification>
</gr:hasPriceSpecification>
</gr:Offering>

</rdf:RDF>


Note: Replace gr:SomeItems (http://purl.org/goodrelations/v1#SomeItems) by gr:Individual if you are describing a unique object of that kind (e.g. antique furniture).

### SPARQL Query

prefix foaf: <http://xmlns.com/foaf/0.1/>
prefix xsd: <http://www.w3.org/2001/XMLSchema#>
prefix pto: <http://www.productontology.org/id/>
prefix gr: <http://purl.org/goodrelations/v1#>
prefix foo: <http://example.com/>

# Find the cheapest offer for a Gas_constant

SELECT * WHERE{
?company gr:offers ?offer .
?offer a gr:Offering .
OPTIONAL {?offer rdfs:label ?label } .
OPTIONAL {?offer gr:name ?label } .
OPTIONAL {?offer rdfs:comment ?label } .
OPTIONAL {?offer gr:description ?label } .
?offer gr:hasPriceSpecification ?p .
?p a gr:UnitPriceSpecification .
?p gr:hasCurrency ?currency .
?p gr:hasCurrencyValue ?price .
?offer gr:includes ?product .
?product a <http://www.productontology.org/id/Gas_constant> .
}
ORDER BY (?price)
LIMIT 10


You can also use the class definitions from this site for better describing the type of your page or product for the Facebook Open Graph Protocol.

Simply define the namespace prefix pto: in the <html> element of your page

<html version="HTML+RDFa 1.1"
xmlns="http://www.w3.org/1999/xhtml"
xmlns:pto="http://www.productontology.org/id/"
>

and use the compact URI (CURIE) pto:Gas_constant in combination with og:type as follows:

	<meta property="og:type" content="pto:Gas_constant"/>


A complete example is here.

## Contact Information

Univ.-Prof. Dr. Martin Hepp

E-Business and Web Science Research Group
Chair of General Management and E-Business
Universität der Bundeswehr München
Werner-Heisenberg-Weg 39
D-85579 Neubiberg, Germany

Phone: +49 89 6004-4217
eMail: mhepp(at)computer.org (preferred mode of communication)
Web: http://www.heppnetz.de/

## Caching Policy

In order to minimize the load on the Wikipedia API, all requests are cached internally for 72 hours. This means that changes to the English Wikipedia will be available in this service within 72 hours or less if the same entry has been requested before. Classes not requested within the last six hours are always guaranteed to be in sync with the latest version in Wikipedia.

The RDF/XML dump file is updated every 12 hours only.

Trademark Disclaimer:  Since this service returns class descriptions for potentially any series of characters, it cannot indicate automatically whether a name is a registered trademark or otherwise protected. If you want us to block a certain name, please send your request including proof of your rights on the name to our contact address listed below.. Any of the trademarks, service marks, collective marks, design rights or similar rights that are mentioned, used, or cited in this service are the property of their respective owners. Their use here does not imply that you may use them for any purpose other than for the same or a similar informational use as contemplated by the original authors of the underlying Wikipedia articles under the CC-BY-SA and GFDL licensing schemes. Productontology.org is neither endorsed by nor affiliated with any of the holders of any such rights and as such cannot grant any rights to use any otherwise protected materials. Your use of any such or similar incorporeal property is at your own risk.

## Acknowledgements

Thanks to Stefano Bertolo, Julien Chaumond, Bob Ferris, Kingsley Idehen, Axel Polleres, Andreas Radinger, Alex Stolz, and Giovanni Tummarello for very valuable feedback, and to Katharina Siorpaes and Daniel Bachlechner, who contributed to the initial analysis of the stability of Wikipedia URIs back in 2007.

The work on The Product Types Ontology has been supported by the German Federal Ministry of Research (BMBF) by a grant under the KMU Innovativ program as part of the Intelligent Match project (FKZ 01IS10022B).

## References

Wikipedia: Gas constant, available at http://en.wikipedia.org/wiki/Gas_constant.

Hepp, Martin: GoodRelations: An Ontology for Describing Products and Services Offers on the Web, Proceedings of the 16th International Conference on Knowledge Engineering and Knowledge Management (EKAW2008), Acitrezza, Italy, September 29 - October 3, 2008, Springer LNCS, Vol 5268, pp. 332-347.

Hepp, Martin; Siorpaes, Katharina; Bachlechner, Daniel: Harvesting Wiki Consensus: Using Wikipedia Entries as Vocabulary for Knowledge Management, IEEE Internet Computing, Vol. 11, No. 5, pp. 54-65, Sept-Oct 2007.