Yahoo奇摩 網頁搜尋

搜尋結果

  1. en.wikipedia.org › wiki › UreaUrea - Wikipedia

    Urea, also called carbamide (because it is a diamide of carbonic acid ), is an organic compound with chemical formula CO (NH2)2. This amide has two amino groups (– NH2) joined by a carbonyl functional group (–C (=O)–). It is thus the simplest amide of carbamic acid .

  2. The double sovereign is a gold coin of the United Kingdom with a nominal value of two pounds sterling (£2). It features the reigning monarch on its obverse and, most often, Benedetto Pistrucci 's depiction of Saint George and the Dragon on the reverse (pictured). It was rarely issued in the first century and a half after its debut in 1820 ...

  3. Isopropyl alcohol ( IUPAC name propan-2-ol and also called isopropanol or 2-propanol) is a colorless, flammable organic compound with a pungent alcoholic odor. [9]

  4. en.wikipedia.org › wiki › AmmoniaAmmonia - Wikipedia

    Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the formula N H 3. A stable binary hydride and the simplest pnictogen hydride, ammonia is a colourless gas with a distinctive pungent smell.

  5. en.wikipedia.org › wiki › ChlorineChlorine - Wikipedia

    Chlorine is a yellow-green gas at room temperature. It is an extremely reactive element and a strong oxidising agent: among the elements, it has the highest electron affinity and the third-highest electronegativity on the revised Pauling scale, behind only oxygen and fluorine.

  6. en.wikipedia.org › wiki › PiPi - Wikipedia

    The number π (/paɪ/; spelled out as "pi") is a mathematical constant that is the ratio of a circle's circumference to its diameter, approximately equal to 3.14159. The number π appears in many formulae across mathematics and physics. It is an irrational number, meaning that it cannot be expressed exactly as a ratio of two integers, although ...

  7. en.wikipedia.org › wiki › ApostropheApostrophe - Wikipedia

    The apostrophe ( ' or ’) is a punctuation mark, and sometimes a diacritical mark, in languages that use the Latin alphabet and some other alphabets. In English, the apostrophe is used for three basic purposes: The marking of the omission of one or more letters, e.g. the contraction of "do not" to "don't"

  1. 其他人也搜尋了