Chemical substance In organic chemistry, there can be more than one chemical compound with the same composition and molecular weight. Generally, these are called isomers. Isomers usually have substantially different chemical properties, and often may be isolated without spontaneously interconverting. A common example is glucose vs. fructose. The former is an aldehyde, the latter is a ketone. Their interconversion requires either enzymatic or acid-base catalysis. However, tautomers are an exception: the isomerization occurs spontaneously in ordinary conditions, such that a pure substance cannot be isolated into its tautomers, even if these can be identified spectroscopically or even isolated in special conditions. A
Chemical safety assessment the European Chemicals Agency as part of the respective registration dossier. The purpose is to ensure that the risks related to the substance are controlled. The chemical safety assessment of a substance comprises the following steps: The European Chemicals Agency (ECHA) has developed a software tool to support industry in preparing a Chemical Safety Assessment (CSA) and Chemical Safety Report (CSR). Chesar Beta version can be downloaded from the Chesar website. Chemical Safety Reports are the main end point for data assessment under REACH (the European Community Regulation on chemicals and their safe use, concerning the Registration, Evaluation, Authorisation and