Chemistry is the science of substances and their transformations. It deals with the basic laws that are necessary for understanding the properties of substances and their change through chemical reactions. Knowledge of the behavior of chemical compounds, their atomic understanding and the application of chemical working methods are also essential for other areas, e.g. for materials science and life sciences (including medicine and pharmacy). Chemistry, therefore, has the rank of cross-sectional science. Almost all problems in industry and technology nowadays also include chemical issues.