Mole (unit) measure the amount of substance (although in practice it is usual). There are many physical relationships between amount of substance and other physical quantities, the most notable one being the ideal gas law (where the relationship was first demonstrated in 1857). The term "mole" was first used in a textbook describing these colligative properties. Chemical engineers use the unit extensively, and decimal multiples may be more suitable for industrial use. For convenience in avoiding conversions in the imperial (or American customary units), some engineers adopted the "pound-mole" (notation "lb-mol" or "lbmol"), which is defined as the number of entities in
Epoxy the ratio of the amount of substance of epoxide groups, "n"(EP), and the mass "m"(B) of the material B, with the SI unit "mol/kg", or the so-called "epoxide equivalent weight", which is the ratio of the mass of a sample B of the resin and the amount of substance of epoxide groups present in that sample B, with the SI unit "kg/mol". The so-called "epoxide equivalent weight" is simply the inverse of the so-called "epoxide number". The specific amount of substance of epoxide groups is used to calculate the mass of co-reactant (hardener) to use when curing epoxy resins. Epoxies