Vybrané termochemické výpočty chemickej reakcie formou webovej služby
The paper deals with providing and use of thermochemical calculations for chemical reaction in a web service form. In the introductory part, sources of thermochemical data are analyzed being currently available in various forms from books to web applications or services. Next section is devoted to selected thermochemical calculations of chemical reactions that the web service implements. The following part presents principles of service-oriented architecture that is used in the web service design. The web service design is based on the above mentioned calculations which are performed using a database of thermochemical properties of substances and the web services providing these properties. Based on thermochemical properties of substances connected with a particular chemical reaction, thermochemical calculations for the chemical reaction are carried out, such as molar heat capacity, enthalpy, entropy, and the Gibbs free energy, as well as logarithm of the equilibrium constant for a given temperature or the temperature range. In the next step, a calculation of the equilibrium composition and the calculation of Gibbs free energy using van't Hoff reaction isobars are performed, which may be implemented for a given temperature, pressure or partial pressure or for their intervals. The web service proposal includes the description of its sources, individual functions, the method of service calling in client's application and a specification of the structure of outputs, as well as error statuses of the service. Designed and implemented web service functions can be used in a variety of client environments. The web service is available through Web Service Description Language file (http://omega.tuke.sk/wsdl/ThermoChemDC.wsdl). The final part of the article deals with the presentation of the web service in the form of a designed multilingual presentation application (http://omega.tuke.sk/tc) with a demonstration of specific calculations. Its output is presented in a table form while, in the case of a temperature range, in a graphical form. The possibilities of the web service, its structure and assessment, as well as further procedures for solving problems are also given.