Presentation on theme: "Some Consumer Chemistry What’s in that stuff and why does it work?"— Presentation transcript:
Some Consumer Chemistry What’s in that stuff and why does it work?
Why do we need soap? Oil and water don’t mix! (Why?) To make them mix (so we can wash the oil away) we use a molecule that has an end that attracts water (hydrophilic) and an end that attracts the non-polar oil (hydrophobic). Soaps are salts of the fatty acids (organic) that make up lipids.
Soap in Action Head (hydrophilic) end of soap molecule attracts water Tail (hydrophobic) end of soap molecule attracts grease Grease
The problems with soap… Hard water contains Mg 2+, Ca 2+, and/or Fe 3+ ions. The soap molecule reacts with these ions and form a precipitate…soap scum!
Soap Alternatives… Detergents are synthetic molecules that have hydrophobic and hydrophilic ends like soap but do not form the insoluble materials with hard water ions. Most modern cleaning products (hand soap, shampoo, toothpaste…) are detergents.
Detergent additives You want your clothes white and bright, right? Textiles tend to fade or turn yellow over time. Manufacturers add products that make you think the clothes are brighter and whiter. Bluing agents (whiteners) absorb yellow light so the clothes don’t look yellow. Brighteners absorb UV light and emit it as visible light so the clothes look brighter.
Detergent additives Enzymes remove protein-based stains by breaking the protein molecules so the trapped colored molecules can be released. They also “chomp” small broken fibers from natural materials. Oxygen releasing materials (bleaching agents) have an oxidizing effect and convert colored compounds to colorless ones.
Fabric Softeners Fabrics feel rough because of small broken fibers on the cloth. Fabric softeners use a lubricating substances that provide a smooth feel and reduce static electricity build-up.
Toothpaste Toothpastes contain one or more of the following: Detergent - to remove grease/oil (sodium lauryl sulfate) Basic compound – to neutralize acid formed by bacteria (CaCO 3 or baking soda and ammonia) Abrasive – to remove material deposited on the mineral tooth surface (silicates…like sand) Coloring agents – to make the toothpaste white (titanium dioxide) or other interesting colors
Toothpaste Toothpastes contain one or more of the following: Fluoride – to produce a harder mineral called hydroxyfluoroapatite from tooth enamel; this is usually sodium fluoride (Fluoristat) Flavoring and sweetening agents – so we will use toothpaste! Sweeteners are artificial, not sucrose! Bleaching agents – to whiten teeth (hydrogen peroxides or related compounds but not bleach)
Sweeteners Sucrose (table sugar) – naturally derived from plants such as sugar cane and beets Aspartame (Equal®) – combination of two amino acids slightly modified
Sweeteners Saccharin (Sweet ‘N Low®) – artifically produced Sucralose (Splenda®) – derived from sucrose with chlorine atoms replacing OH groups
Sweetners Stevioside (Truvia®) – naturally derived from the stevia plant
Sunscreens Contain molecules that absorb and/or reflect some UV-A and UV-B rays Sun Protection Factor (SPF) Argh! SPF indicates how much longer it will take for skin to redden…An SPF factor of 15 means that it will take about 15 times longer to get red when exposed…if applied correctly!
Sunscreens SPF% UV absorbed
Drug NameConcentration, %Absorbance Aminobenzoic acidUp to 15UV-B Avobenzone2-3UV-A I CinoxateUp to 3UV-B DioxybenzoneUp to 3UV-B, UV-A II Ecamsule*2UV-A II EnsulizoleUp to 4UV-B HomosalateUp to 15UV-B MeradimateUp to 5UV-A II OctocryleneUp to 10UV-B OctinoxateUp to 7.5UV-B OctisalateUp to 5UV-B OxybenzoneUp to 6UV-B, UV-A II Padimate OUp to 8UV-B SulisobenzoneUp to 10UV-B, UV-A II Titanium dioxide2 to 25Physical Trolamine salicylateUp to 12UV-B Zinc oxide2 to 20Physical