scum formation

What Is The Chemical Formula Of Scum? CaCO3 is found everyday in hard water. but the reaction with soap will not be different between the two, as an insoluble Ca salt of the fatty acid found in soap will form (scum). 2C17H35COO^- + Ca^2+ ===> (C17H35COO)2Ca which is insoluble and referred to as scum. What