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.
A substance is simply a pure form of matter. In other words, a substance is matter than contains only one type of atom or molecule. Pure substances can be further divided into two sub categories: elements and compounds. Elements are the simplest form of matter, which means they cannot be broken down into smaller components physically or chemically.