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  • General

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  • 碳单体和聚聚体

    Great Seal of the United States featuring the motto 'E pluribus unum' and an eagle.

    You probably recognize this image as the great seal of the United States. The motto on the seal, E pluribus unum , is Latin for “out of many, one.” It refers to the formation of one country out of many states. Large carbon compounds could have the same motto. Can you guess why? In this lesson, you’ll find out.
    ::你可能承认这一形象是美国的伟大印章。 印章上的座右铭E pluribus unum是拉丁文中的“由众多国家组成的 ” 。 它指在许多州中形成一个国家。 大型碳化合物可能有同样的座右铭。 你能猜到原因吗?在这个教训中,你会发现这一点。

    Out of Many, One
    ::众人中的一个,

    Carbon has a unique ability to form with many other atoms. It can bond with other carbon atoms as well as with atoms of other . Because of this ability, carbon often forms polymers . A polymer is a large molecule that is made out of many smaller molecules that are joined together by covalent bonds. The smaller, repeating molecules are called monomers . (The prefix mono - means “one” and the prefix poly - means “many.”) Polymers may consist of just one type of monomer or of more than one type. Polymers are similar to the strings of beads pictured in the Figure  . Like beads on a string, monomers in a polymer may be all the same or different from one another.
    ::碳具有与其他许多原子形成的独特能力。 它可以与其他碳原子以及其它原子结合。 由于这种能力, 碳常常形成聚合物。 聚合物是一种大型分子, 由许多较小的分子组成, 由共价键结合。 较小的重复分子称为单体。 (前缀单体“ one” 和前缀聚体“ many ” 。 )聚合物可能只是一种单体或一种以上的单体。 聚合物与图中所描绘的珠子弦相似。 就像串线上的珠一样, 聚合物中的单体可能完全相同或不同。

    Beaded strings representing polymers, illustrating different monomer types and arrangements.

    Natural Carbon Polymers
    ::自然碳聚碳体

    Many polymers of carbon occur naturally. Two examples are rubber and cellulose.
    ::许多碳聚合物自然产生,其中两个例子是橡胶和纤维素。

    • Rubber is a natural polymer of the monomer named isoprene (C 5 H 8 ). This polymer comes from rubber trees, which grow in tropical areas. Structural formulas for rubber and isoprene are shown in the Figure  . Note that just a small section of the rubber polymer is represented by the structural formula.
      ::这种聚合物来自在热带地区生长的橡胶树。图中显示了橡胶和同位素的结构性配方。请注意,橡胶聚合物中只有一小部分是由结构配方表示的。
    • Cellulose is a natural polymer of the monomer named glucose (C 6 H 12 O 6 ). This polymer makes up the cell walls of plants and is the most common in living things. Structural formulas for cellulose and glucose are also shown in the Figure  ). As you can see from the structural formula for cellulose, when two glucose monomers bond together, a molecule of water (H 2 O) is released.
      ::纤维素是单体称为葡萄糖(C6H12O6)的天然聚合物,这种聚合物构成植物的细胞壁,在生物中最为常见。纤维素和葡萄糖的结构配方也在图中显示。从纤维素的结构配方中可以看出,当两个葡萄糖单体结合在一起时,释放出水分子(H2O)。

    Structural formulas for rubber and cellulose with isoprene and glucose shown.

    Q: How are the glucose molecules arranged in the cellulose polymer?
    ::问题:葡萄糖分子在纤维素聚合物中是如何排列的?

    A: The glucose molecules alternate between right-side up and upside down.
    ::A: 葡萄糖分子在右侧向上和向上之间交替。

    Synthetic Carbon Polymers
    ::合成碳聚合物

    Synthetic carbon polymers are produced in labs or factories. Plastics are common examples of synthetic carbon polymers. You are probably familiar with the plastic called polyethylene. All of the plastic items pictured in the Figure  are made of polyethylene. It consists of repeating monomers of ethylene (C 2 H 4 ). Structural formulas for ethylene and polyethylene are also shown in the Figure  . 
    ::合成碳聚合物在实验室或工厂生产,塑料是合成碳聚合物的常见例子,你可能熟悉称为聚乙烯的塑料,图中描绘的所有塑料物品都是聚乙烯,包括乙烯(C2H4)。图中还显示了乙烯和聚乙烯的结构公式。

     

    Milk containers, a plastic bag, and toys made of polyethylene are displayed.

    Chemical structure representation of synthetic carbon polymers in a science lesson.

    Summary
    ::摘要

    • Carbon has a unique ability to form many covalent bonds, so it often forms polymers. A polymer is a large molecule that is made up of many smaller, repeating molecules, called monomers, which are joined together by covalent bonds.
      ::碳具有形成许多共价债券的独特能力,因此常常形成聚合物。 聚合物是一种大型分子,由许多较小的重复分子组成,叫做单体分子,由共价债券结合在一起。
    • Natural polymers include rubber and cellulose. Synthetic polymers include plastics such as polyethylene.
      ::天然聚合物包括橡胶和纤维素,合成聚合物包括塑料,如聚乙烯。

    Review
    ::回顾

    1. Define polymer and monomer.
      ::定义聚合物和单体。
    2. Describe an example of a natural carbon polymer.
      ::描述天然碳聚合物的例子。
    3. What are some uses of synthetic carbon polymers?
      ::合成碳聚合物有哪些用途?

    Explore More
    ::探索更多

    Watch the video about polymers and then answer the questions below.
    ::观看关于聚合物的视频,然后回答下面的问题。

     

     

    1. Define the two parts of the word polymer, and give a literal definition of polymer.
      ::定义聚合物一词的两个部分,并给出聚合物的字面定义。
    2. Describe two properties of polymers that depend on their long-chain structure.
      ::描述取决于其长链结构的聚合物的两个特性。
    3. Name three items that consist of or contain polymers.
      ::列出三个由聚合物组成或含有聚合物的项目。