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:

Copper molecule shows promise in fighting against cancer | EVISA's News
Journals database: Hydrology and Earth System Sciences
Company database: Trans Tech Publications Inc.
Books and Special Issues on Elemental Speciation (published since 2016) | EVISA's News
Link database: Chemical Fact Sheet: Promethium
Company database: Institute of Physics (IOP)
Brief summary: Speciation analysis for the study of metallodrugs and their biomolecular interactions | EVISA's News
Instrument database: Knauer GmbH - Smartline RI Detector 2300
Climate change and overfishing are increasing toxic mercury levels in fish | EVISA's News
Nutrigenomics: The role of chromium for fat metabolism revisited | EVISA's News
Exchange of sulfur against selenium makes insulin analogue last longer | EVISA's News
Link database: IMOA: Molybdenum - Industrial and Environmental Exposure of Humans
New study shows: Coastal water, not sediment, predicts methylmercury bioaccumulation in the marine food web | EVISA's News
All about food sciences | EVISA's News
Link database: Australia: University of Western Sydney: Biologically Active Drugs by Design Group
Link database: Aluminum Geochemistry Eh-pH, pe-pH diagrams and Solubility
Company database: Singapore National Institute of Chemistry (SNIC)
Company database: British Ecological Society (BES)
Link database: Chemical Fact Sheet: Germanium
Efficiency of some papillomavirus vaccines is reduced in the presence of thimerosal | EVISA's News