Author: Amanda Yarnell
Chemistry Connections: Acids/Bases, Bonding, Solids/Liquids/Gases, Solutions
Description: Discusses the relatively short history of cat litter (<60 years) and the four main types of cat litter—Fuller’s earth, bentonite (Montmorillonite), silica gels and plant-derived materials like Swheat Scoop. Talks about the chemistry of each type, including odor control (by protonation of NH3 to NH4+, absorbents, fragrances and antibacterial agents) and clumping of clays (absorption of water between layers of clay, causing swelling of the clay). Molecular models of Montmorillonite before and after the addition of water are shown.
Author: Christen Brownlee
Chemistry Connections: Acids/Bases, History/Biography, Organic/Biochemistry, Reactions, Solutions
Description: Recounts attempts to find an easy-to-use colorimetric urine test for diabetes. Includes early chemical testing, from the use of copper (II) sulfate-sodium hydroxide-ammonia reagent, to the advance made by Walter Compton who combined the reagents into tablet form (called Clinitest), to the modification made by Helen and Al Free which was a tablet that tested urine for ketone bodies. Describes the paper strip test, also developed by the Frees, which uses glucose enzymes to test for sugar in urine. Eventually the paper strip developed by the Frees contained ten tests in a single strip. The test strips are called Multistix-10SG. Article includes photos of the test strips. An interview with Helen Free follows the article.
Author: Helen Herlocker
Chemistry Connections: Acids/Bases, Equilibrium, Reactions, Sustainability
Description: Explains the greenhouse effect; role of atmospheric chemicals absorbing infrared radiation. Carbon dioxide, water vapor, methane, nitrous oxide, ozone, dichlorodifluoromethane, trichlorofluoromethane listed with their relative effectiveness in absorbing infrared. Diagrams are included.