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Phenolphthalein (/ fɛˈnɒl (f) θəliːn / [citation needed]feh-NOL (F)-thə-leen) is a chemical compound with the formula C 20 H 14 O 4 and is often written as " HIn ", " HPh ", " phph " or simply " Ph " in shorthand notation. Phenolphthalein is often used as an indicator in acid–base titrations. For this application, it turns colorless in ...
Base (chemistry) Soaps are weak bases formed by the reaction of fatty acids with sodium hydroxide or potassium hydroxide. In chemistry, there are three definitions in common use of the word " base ": Arrhenius bases, Brønsted bases, and Lewis bases. All definitions agree that bases are substances that react with acids, as originally proposed ...
The Kastle–Meyer test is a presumptive blood test, first described in 1903, in which the chemical indicator phenolphthalein is used to detect the possible presence of hemoglobin. It relies on the peroxidase -like activity of hemoglobin in blood to catalyze the oxidation of phenolphthalin (the colorless reduced form of phenolphthalein) into ...
Human hair color is the pigmentation of human hair follicles and shafts due to two types of melanin: eumelanin and pheomelanin. Generally, the more melanin present, the darker the hair. Its tone depends on the ratio of black or brown eumelanin to yellow or red pheomelanin. Melanin levels can vary over time, causing a person's hair color to ...
The dark markings on both birds are due to the black pigment eumelanin. Biological pigments, also known simply as pigments or biochromes, [1] are substances produced by living organisms that have a color resulting from selective color absorption. Biological pigments include plant pigments and flower pigments.
Litmus is a water-soluble mixture of different dyes extracted from lichens. It is often absorbed onto filter paper to produce one of the oldest forms of pH indicator, used to test materials for acidity. In an acidic medium, blue litmus paper turns red, while in a basic or alkaline medium, red litmus paper turns blue.
The Fitzpatrick scale (also Fitzpatrick skin typing test; or Fitzpatrick phototyping scale) is a numerical classification schema for human skin color. It was developed in 1975 by American dermatologist Thomas B. Fitzpatrick as a way to estimate the response of different types of skin to ultraviolet (UV) light. [ 2 ]
Cyanosis is the change of body tissue color to a bluish-purple hue, as a result of decrease in the amount of oxygen bound to the hemoglobin in the red blood cells of the capillary bed. [1] Cyanosis is apparent usually in the body tissues covered with thin skin , including the mucous membranes , lips, nail beds , and ear lobes. [ 1 ]