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Water Chemistry
Published in Frank R. Spellman, The Science of Water, 2020
Water, H2O, is a compound. As stated, compounds are chemical substances made up of two or more elements bonded together. Unlike elements, compounds can be separated into simpler substances by chemical changes. Most forms of matter in nature are composed of combinations of the 100+ pure elements.
Basic Water Chemistry
Published in Frank R. Spellman, Handbook of Water and Wastewater Treatment Plant Operations, 2020
Water (H2O) is a compound. As stated, compounds are chemical substances made up of two or more elements bonded together. Unlike elements, compounds can be separated into simpler substances by chemical changes. Most forms of matter in nature are composed of combinations of the 100 pure elements.
Proposal for a neurotoxic classification for chemicals at work
Published in Archives of Environmental & Occupational Health, 2021
Shiraz Dib, Thi-Hai-Yen Nguyen, Julie Bodin, Mélanie Bertin, Alexis Descatha, Yves Roquelaure, Nathalie Bonvallot
Candidate chemical substances or products for classification were selected based on the questionnaires used in these occupational studies (Table 1). Nineteen chemical substances, sixteen chemical families, including metal derivatives, ten complex mixtures, such as fuels, hydrocarbons, and resins, and fourteen product categories that include a large variety of compounds (pesticides, solvents, or other industrial chemicals) were identified. Chemical substances are single chemicals characterized by a unique chemical structure and a chemical abstract system registry number (CAS). Chemical families correspond to metals and their derivatives and organic chemicals characterized by the same functional group, such as alcohols, acid phthalic esters, etc. Complex mixtures are mixtures containing many components in inexact proportions characterized for their technical properties, such as fuels. Product categories include various chemicals characterized by their use, such as paints, pesticides, etc.