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:

Link database: EFSA: Scientific Opinion on Arsenic in Food [1]
Instrument database: Shimadzu Corporation - MultiSPec 1501
Material database: SUPELCO by Sigma-Aldrich - Se-(Methyl)selenocysteine Hydrochloride
Link database: Asics Padel Competition
EVISA Workshop on: Mercury speciation analysis - The basis for sound risk assessment, and optimized remediation strategies for contaminated soils, sediments and sludge | EVISA's Agenda of Events
Link database: Thimerosal - Harmless Vaccine Preservative Or Just Another Toxic Organic Mercury Compound?
New Study Finds: Thimerosal Induces Autism-like Neurotoxicity | EVISA's News
Link database: Singapore: Laboratory of Bioinorganic Chemistry: Dr. Ang Wee Han
Link database: Fluoride and Fluorinated Pesticides
Company database: GNR Analyytical Instruments Group
Link database: Toxicity of Trimethylsilanol
New arsenic species detected in carrot samples | EVISA's News
Company database: British Society for Allergy & Clinical Immunology (BSACI)
New study shows: Coastal water, not sediment, predicts methylmercury bioaccumulation in the marine food web | EVISA's News
Journals database: Annals of the New York Academy of Sciences
EVISA's Privacy Policy | EVISA's News
A short review of EVISA's activities during the year 2008 | EVISA's News
Material database: National Research Council of Canada (NRC - CNRC) - NIMS-1: Natural abundance inorganic mercury isotopic certified reference material
Journals database: Geomicrobiology Journal
Why should elemental speciation be done ?