in chemistry: The thermodynamically effective concentration of a chemical species or component. In solutions with high ionic strengths, ions interact with each other and are not totally independent chemical units. The interactions affect the boiling point, freezing point, and other properties of the solution. The effective concentration (activity) of an ion in a high ionic strength solution is usually less than the total number of moles in the solution. The activity of an ion is calculated by multiplying its molal concentration by its activity coefficient. In very dilute solutions, activities and molal concentrations are essentially equal.

The term "activity" was found in the following pages:

Directory of scientists: John H. Duffus
Geochemical Speciation & Bioavailability of Trace Elements: Progress, Challenges & Future Trends | EVISA's Agenda of Events
Journals database: European Journal of Neurology
New Study Finds: Thimerosal Induces Autism-like Neurotoxicity | EVISA's News
Company database: Canon Communications LLC
Journals database: Environmental Geochemistry and Health
Company database: Australian Science Teachers Association (ASTA)
Fractionation as a first step towards speciation analysis | EVISA's News
Journals database: Accounts of Chemical Research
Effect of dissolved humic acid on the bioavailability of lead from contaminated soil | EVISA's News
Speciation and Toxicity: Humic Acids Increase Lead Bioavailability and Toxicity for Marine Invertebrates | EVISA's News
Iron-reducing bacteria could detoxify hexavalent chromium | EVISA's News
Link database: Speciation, bioavailability and antigenotoxicity of Selenium species present in Selenium enriched natural products.
EFSA: Scientific Opinion on Arsenic in Food | EVISA's News
Material database: National Research Council of Canada (NRC - CNRC) - NIMS-1: Natural abundance inorganic mercury isotopic certified reference material
Journals database: American Journal of Human Biology
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Journals database: Cell Biology and Toxicology
Company database: Nuclear Research Institute Rez plc
Journals database: Environmental and Molecular Mutagenesis