| 释义 |
litmus
lit·mus L0202700 (lĭt′məs)n. A water-soluble bluish powder derived from certain lichens that changes to red with increasing acidity and to deeper blue with increasing basicity.
[Middle English litemose (of Scandinavian origin; akin to Old Norse litmosi, dyer's herbs litr, color, dye + mosi, bog, moss) and Middle English lykemose (from Middle Dutch lijkmoes, variant of lēcmoes : lēken, to drip + moes, moss).]litmus (ˈlɪtməs) n (Elements & Compounds) a soluble powder obtained from certain lichens. It turns red under acid conditions and blue under basic conditions and is used as an indicator[C16: perhaps from Scandinavian; compare Old Norse litmosi, from litr dye + mosi moss]lit•mus (ˈlɪt məs)
n. a blue coloring matter obtained from certain lichens, esp. Roccella tinctoria, that turns blue in alkaline solution and red in acid solution: widely used as a chemical indicator. [1495–1505; earlier lytmos < Old Norse litmosi dye-moss =lit- color, dye + mosi moss] lit·mus (lĭt′məs) A colored powder, obtained from certain lichens, that changes to red in an acid solution and to blue in an alkaline solution. ♦ Litmus is typically added to paper to make litmus paper, which is used to determine whether a solution is basic or acidic.Thesaurus| Noun | 1. |  litmus - a coloring material (obtained from lichens) that turns red in acid solutions and blue in alkaline solutions; used as a very rough acid-base indicatorlitmus testacid-base indicator - an indicator that changes color on going from acidic to basic solutionslitmus paper - unsized paper treated with litmus for use as an acid-base indicator |
Translationslitmus
litmus test1. A chemical test used to determine acidity or alkalinity in a solution. The students performed a litmus test in class to learn whether the chemical solution was an acid or a base.2. A test used to determine someone's true intentions or beliefs. I used his reaction to my favorite movie as a litmus test to determine if he was worth dating.See also: litmus, testlitmus test 1. Lit. a test used to determine the acidity or alkalinity of chemical substances. (Acid turns litmus paper red and alkaline compounds turn it blue.) I used a litmus test to show that the compound was slightly acid. 2. Fig. a question or experiment that seeks to determine the state of one important factor. His performance on the long exam served as a litmus test to determine whether he would go to college. The amount of white cells in my blood became the litmus test for diagnosing my disease.See also: litmus, testa litmus test JOURNALISMCOMMON If something is a litmus test of the quality or success of a particular thing, it is an effective way of proving it or measuring it. My personal litmus test when I have to decide whether to keep or discard something is whether or not I look at and enjoy it every day. The success of wind power represents a litmus test for renewable energy. Note: Litmus paper is used to test the acidity of substances. It turns red in acid conditions and blue in alkaline conditions. See also: litmus, testlitmus
litmus, organic dye usually used in the laboratory as an indicator of acidity or alkalinity (see acids and basesacids and bases,
two related classes of chemicals; the members of each class have a number of common properties when dissolved in a solvent, usually water. Properties
..... Click the link for more information. ). Naturally pink in color, it turns blue in alkali solutions and red in acids. Commonly, paper is treated with the coloring matter to form so-called litmus paper. Litmus is extracted, chiefly in the Netherlands, from certain lichens (see archilarchil
or orchil
, blue, red, or purple dye extracted from several species of lichen, also called orchella weeds, found in various parts of the world. Commercial archil is either a powder (called cudbear), a pasty mass (called archil), or a drier paste (called persis).
..... Click the link for more information. ), which are mashed, treated with potassium carbonate and ammonia, and allowed to ferment. The resulting product is mixed with various colorless substances, such as chalk or gypsum, and is sold in dark blue lumps, masses, or tablets. The active component of litmus, i.e., the part sensitive to acids or bases, is called erythrolitmin.Litmus a dye extracted from certain species of lichen (for example, Roccella tinctoria). The composition of litmus is complex and has not yet been fully established. The pigment component is the weak acid azolitmin, which yields blue salts. Litmus is used as an indicator: it turns red in an acid medium and blue in an alkaline medium. Test papers impregnated with the dye are generally the form used. litmus[′lit·məs] (materials) Blue, water-soluble powder from various lichens, especially Variolaria lecanora and V. rocella ; turns red in solutions at pH 4.5, and blue at pH 8.3; used as an acid-base indicator. Also known as lacmus; lichen blue. litmusAn organic chemical indicator of acidity or alkalinity; is red in color for pH values below 4.5 and blue above 8.3.litmus a soluble powder obtained from certain lichens. It turns red under acid conditions and blue under basic conditions and is used as an indicator litmus
litmus [lit´mus] a blue pigment prepared from Rocella tinctoria and other lichens.litmus paper absorbent paper impregnated with a solution of litmus, dried and cut into strips. It is used to indicate the acidity or alkalinity of solutions. If dipped into alkaline solution it remains blue; acid solution turns it red. It is used to test urine and other body fluids; it has a pH range of 4.5 to 8.3.lit·mus (lit'mŭs), [old C.I. 1242] A blue coloring matter obtained from Roccella tinctoria and other species of lichens, the principal component of which is azolitmin; used as an indicator (reddened by acids and turned blue again by alkalies). [a corruption of lacmus, fr. Dutch lakmoes] lit·mus (lit'mŭs) A blue coloring material obtained from Roccella tinctoria and other lichens, the principal component of which is azolitmin; used as an indicator (reddened by acids and turned blue again by alkalies). [a corruption of lacmus, fr. Dutch lakmoes]litmus A powder derived from certain lichens that contains the natural dye azolitmin. This turns red in an acidic medium at pH below 4.5 and blue at an alkaline pH above 8.3. Paper strips impregnated with litmus form convenient indicators for checking urine acidity.litmus
Related to litmus: litmus paperSynonyms for litmusnoun a coloring material (obtained from lichens) that turns red in acid solutions and blue in alkaline solutionsSynonymsRelated Words- acid-base indicator
- litmus paper
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