The relative amount of a substance when combined or mixed with other substances. Concentration can be expressed as mole fraction, mass fraction, or component mole or mass density. Examples: yi = 2 ppm mole fraction; wi = 0.50 mass fraction; ci = 0.03 kmole/m3.
Notice: The AIChE website is undergoing an ecommerce system upgrade to better serve you. Between 7 a.m. (EST) Friday, December 6 and 9 a.m. (EST) Monday, December 9 you will not be able to purchase or renew any AIChE products or services through the website. Customer Service phone lines are open 9 a.m. to 5 p.m. Monday through Friday... Learn more