Bottle of solution of sodium dodecyl sulfate for use in the laboratory. The critical micelle concentration (CMC) in pure water at 25 Â°C is 8.2 mM, and the aggregation number at this concentration is usually considered to be about 62. The micelle ionization fraction (Î±) is around 0.3 (or 30%).
Definition: A pure substance is a sample of matter with both definite and constant composition with distinct chemical properties.
1. that which makes up something, esp a physical object; material. 2. substance that occupies space and has mass, as distinguished from substance that is mental, spiritual, etc. 3. substance of a specified type: vegetable matter; reading matter. 4. (sometimes foll by: of or for) thing; affair; concern; question: a matter of taste; several matters to attend to; no laughing matter.