Hard+Water's+Effect+on+Soap+and+Detergent

**Keywords:** Micelle; HLB value; Hydrophilic/Lipophilic; Precipitate. [|Graph[1.docx]]
 * Hard Water’s Effect on Soap and Detergent. Evan McMillan.** This lab involved observing and quantifying the effects of hard water on the different soaps and a detergent. Soaps and detergents carry out similar but slightly different processes when used. Soap molecules cluster together to form structures called micelles which maintain a negative charge, attracting dirt and oil while repelling other micelles. Detergents act as a surfactant by lowering the surface area of water, making it more likely to interact with oil and grease instead of itself. Minerals present in hard water can hinder both of these processes. Soap molecules can be converted by minerals into a precipitate, or soap scum, which is not soluble in water. Surfactants depend on balance between hydrophilic grouping (water loving) and lipophilc groupings (oil loving) known as the Hydrophilic-Lipophilic Balance (HLB value). As this balance goes up, a substance will be more soluble in water. Detergents usually maintain a 0HLB value, meaning that it has an equal amount of lipophilic and hydrophilic groupings. A regular soap, an antibacterial hand soap, and a detergent will be mixed with a hard water solution. After two days each sample was filtered and the mass of precipitates was calculated. The antibacterial soap used did not create a precipitate because the increase in mass of the filter paper after was just .05g (the same as the hard water control). A .18 gram increase for the regular soap indicates a small precipitate formed. The detergent solution had a .52 gram increase which indicates that something much heavier formed as a result of mixing with the water. These different mass increases can be explained through the different process of how soaps and detergents clean and also their structural makeup.