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:

Company database: American Thoracic Society (ATS)
Speciation analysis for cancer diagnosis | EVISA's News
New arsenic species detected in carrot samples | EVISA's News
A new Selenium-containing compound, Selenoneine, found as the predominant Se-species in the blood of Bluefin Tuna | EVISA's News
ORNL scientists solve mystery about mercury methylation | EVISA's News
Company database: SocietÓ Italiana di Biologia Sperimentale (SIBS)
Link database: Singapore: Laboratory of Bioinorganic Chemistry: Dr. Ang Wee Han
New Study Finds: Thimerosal Induces Autism-like Neurotoxicity | EVISA's News
Toxicity and bioavailability of different selenium metabolites | EVISA's News
Material database: National Research Council of Canada (NRC - CNRC) - MESS-3 Marine Sediment Reference Materials for Trace Metals and other Constituents
User statistics of EVISA's web portal | EVISA's News
Link database: Metals and trace elements in the diet and by injection
Material database: SUPELCO by Sigma-Aldrich - Se-(Methyl)selenocysteine Hydrochloride
Directory of scientists: Panayot Petrov
Iron-reducing bacteria could detoxify hexavalent chromium | EVISA's News
EVISA welcomed its 15 Millionth User | EVISA's News
Directory of scientists: Alfredo Sanz-Medel
New study reports evidence for carcinogenic chromium(VI) compounds in chromium(III)-treated living cells | EVISA's News
Research fields related to elemental speciation
Directory of scientists: Evert Nieboer