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  • General

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  • 不饱饱不饱的碳氢化合物

    Comparison of cooking oil and butter, illustrating solid and liquid fat differences.

    Look at the difference between cooking oil and butter. Fats can be either , like oil, or , like butter, at room depending on their chemical structure. Saturated fats are straight in structure and tightly packed together to form a solid at room temperature. Double and triple bonds in unsaturated fats make them easier to break down at lower temperatures.

    What Are Unsaturated Hydrocarbons?
    ::什么是不饱和碳氢化合物?

    are compounds that contain only carbon and hydrogen. The carbon atoms in hydrocarbons may share single, double, or triple . contain at least one double or triple bond between carbon atoms. They are classified on the basis of their bonds as alkenes , aromatic hydrocarbons , or alkynes .
    ::碳氢化合物中碳原子可共享单一、双倍或三倍碳原子,碳原子之间至少含有一个双倍或三倍的联结。根据碳原子的联结,碳原子可分类为代谢物、芳香碳氢化合物或 alkynes。

    Q: Why do you suppose hydrocarbons with double or triple bonds are called unsaturated?
    ::问:为什么你认为碳氢化合物 与双三债券 被称为不饱和?

    A: A carbon always forms four covalent bonds. Carbon atoms with double or triple bonds are unable to bond with as many hydrogen atoms as they could if they were joined only by single bonds. This makes them unsaturated with hydrogen atoms.
    ::A:碳总是形成四种共价债券。 具有双倍或三倍债券的碳原子无法与尽可能多的氢原子连接,如果它们只有单一债券加入的话。 这使得它们不饱和氢原子。

    Alkenes
    ::代数

    Unsaturated hydrocarbons that contain one or more double bonds are called alkenes . The name of a specific alkene always ends in –ene and has a prefix indicating the number of carbon atoms. The structural formula in the Figure represents the smallest alkene, named ethene, which has two carbon atoms and four hydrogen atoms (C 2 H 4 ). Ethene is produced by most fruits and vegetables. It speeds up ripening. The Figure show the effects of ethene on bananas.
    ::不饱和碳氢化合物含有一种或多种双倍债券,称为Alkenes。特定烷的名称总是以-ene结尾,并有一个前缀表示碳原子的数量。图中的结构公式代表最小的烷,称为乙烯,它有两个碳原子和四个氢原子(C2H4)。Ethene是由大多数水果和蔬菜生产的。它加速成熟。图显示了乙烯对香蕉的影响。

    Structural formula of ethene with bananas: one set stored in ethene-absorbing bag, the other without.

    The bananas on the left were stored in a special bag that absorbs ethene. The bananas on the right were stored without a bag.
    ::左边的香蕉存放在一个吸收乙烯的特殊袋里,右边的香蕉没有袋子。

    Alkenes can have different shapes. They can form straight chains, branched chains, or rings. Alkenes with the same atoms but different shapes are called . Smaller alkenes have relatively high and points, so they are at room temperature. Larger alkenes have lower boiling and melting points, so they are liquids or waxy solids at room temperature.
    ::Alkenes 可以有不同的形状。 它们可以形成直链, 分支链条, 或环。 Alkenes 也可以形成相同的原子, 但被称为不同的形状 。 Smaller alkenes 具有相对高的点和点, 所以它们处于室温。 大的Alkenes 具有较低的沸点和熔点, 所以它们是在室温下的液体或蜡状固体 。

    Aromatic Hydrocarbons
    ::芳芳烃烃

    Unsaturated hydrocarbons called aromatic hydrocarbons are cyclic hydrocarbons that have double bonds. These compounds have six carbon atoms in a ring with alternating single and double bonds. The smallest aromatic hydrocarbon is benzene, which has just one ring. Its structural formula is shown in the Figure . Larger aromatic hydrocarbons consist of two or more rings, which are joined together by bonds between their carbon atoms. The name of aromatic hydrocarbons comes from their strong aroma, or scent. That’s why they are used in air fresheners and mothballs.
    ::称为芳烃的不饱和碳氢化合物是循环碳氢化合物,具有双重联系。这些化合物在环状中拥有六个碳原子,具有交替的单环和双环。最小的芳烃是苯,只有一个环。其结构公式在图中显示。较大的芳烃由两个或两个以上的环组成,由碳原子之间的联结组成。芳烃的名称来自其强大的芳香或气味。这就是为什么它们被用于空气清新剂和蛾球。

    Structural formula of benzene, a six-carbon aromatic hydrocarbon with alternating double bonds.

    Q: How many bonds does each carbon atom in benzene form?
    ::问题:每个苯形式的碳原子有多少债券?

    A: Each carbon atom forms four covalent bonds. Carbon atoms always form four covalent bonds, regardless of the atoms to which it bonds.
    ::A:每个碳原子形成四个共价债券。碳原子总是形成四个共价债券,而不论其与原子的关系如何。

    Alkynes
    ::ALkynes

    Unsaturated hydrocarbons that contain one or more triple bonds are called alkynes . The names of specific alkynes always end in –yne and have a prefix for the number of carbon atoms. The structural formula in the Figure represents the smallest alkyne, named ethyne, which has two carbon atoms and two hydrogen atoms (C 2 H 2 ). Ethyne is also called acetylene. It is burned in acetylene torches, like the one pictured in the Figure . The flame of an acetylene torch is so hot that it can melt metal .
    ::含有1个或3个以上的三联键的不饱和碳氢化合物被称为 alkynes。 特定的 alkynes的名字总是以-yne结尾, 并有一个碳原子数的前缀。 图中的结构公式代表最小的 alkyne, 名叫ethyne, 它有两个碳原子和两个氢原子( C2H2)。 乙炔也被称为乙炔。 它燃烧在乙炔火炬中, 就像图中描绘的一样。 乙炔火炬的火焰非常热, 足以熔化金属 。

    Structural formula of ethyne (C2H2) showing carbon atoms connected by a triple bond.

    Cutting metal with an acetylene torch, producing sparks and intense light.

    Cutting metal with an acetylene (ethyne) torch.
    ::使用乙炔(乙烯)火炬切割金属。

    Alkynes may form straight or branched chains. They rarely occur in ring shapes. In fact, alkynes of all shapes are relatively rare in nature.
    ::藻类可能形成直链或分支链。 它们很少以环形形式出现。 事实上,所有形状的藻类都相对罕见。

    Summary
    ::摘要

    • Unsaturated hydrocarbons are hydrocarbons with at least one double or triple bond between carbon atoms.
      ::不饱和碳氢化合物是碳原子之间至少有一个双倍或三倍联结的碳氢化合物。
    • Alkenes are unsaturated hydrocarbons with at least one double bond between carbon atoms.
      ::代谢物是不饱和的碳氢化合物,碳原子之间至少有一种双倍联系。
    • Aromatic hydrocarbons are unsaturated cyclic hydrocarbons with alternating single and double bonds between carbon atoms.
      ::芳烃是不饱和的循环碳氢化合物,碳原子之间有交替的单一和双重联系。
    • Alkynes are unsaturated hydrocarbons with at least one triple bond between carbon atoms.
      ::烷是不饱和的碳氢化合物,碳原子之间至少有一个三联体。

    Review
    ::回顾

    1. What does it mean for a hydrocarbon to be unsaturated?
      ::碳氢化合物不饱和意味着什么?
    2. Which chemical formula could represent an unsaturated hydrocarbon?
      1. CH 4
        ::CH4 CH4 CH4 CH4 CH4 CH4 CH4 CH4 CH4 CH4 CH4 CH4 CH4 CH4 CH4 CH4 CH4 CH4 CH4
      2. C 2 H 6
        ::C2H6 C2H6
      3. C 3 H 8
        ::C3H8 C3H8
      4. C 2 H 2
        ::C2H2 C2H2

      ::哪种化学公式可以代表一种不饱和碳氢化合物? CH4 C2H6 C3H8 C2H2
    3. Which of the following hydrocarbons has a double bond between carbon atoms?
      1. propane
        ::丙烷
      2. hectane
        ::赫克纳
      3. ethyne
        ::赛瑞
      4. hexene
        ::十六烯

      ::下列哪一种碳氢化合物在碳原子之间具有双重联系?
    4. Describe an aromatic hydrocarbon
      ::描述芳香烃

    Resources
    ::资源