Section outline

  • General

    Collapse all Expand all

  • 更换反应

    A stunt man hangs from a helicopter amidst smoke during an action scene.

    What a job! The man hanging from the burning helicopter in the photo above is a stunt man. He fills in for the lead actor in the movie in dangerous scenes like this one. Like other stunt workers, he has special training to do such dangerous work as safely as possible. Replacing actors with stunt workers is common in action movies. Some also involve replacements. More reactive replace less reactive elements in compounds. These reactions are called replacement reactions.
    ::上面照片上燃烧的直升机上挂着的男子是一个特技演员。 他在这个危险场景中充任电影主演。 与其他特技工作者一样, 他接受特别训练, 尽可能安全地从事这种危险的工作。 在动作电影中, 以特技工作者取代演员是常见的。 有些还涉及替换。 更多的反应取代了复合体中反应较少的元素。 这些反应被称为替换反应 。

    What Is A Replacement Reaction?
    ::什么是替换反应?

    A occurs when elements switch places in compounds. This type of reaction involves (electrically charged versions of atoms) and . These are compounds in which positive ions of a metal and negative ions of a are held together by . Generally, a more reactive element replaces an element that is less reactive, and the less reactive element is set free from the . There are two types of replacement reactions: single and double. Both types are described below.
    ::当元素在化合物中切换位置时即发生。这种反应涉及(电荷原子的版本)和。这些是金属正离子和一个物体负离子的混合体。一般而言,反应性较强的元素取代反应性较弱的元素,反应性较弱的元素不受反应影响。有两种替代反应:单倍和双倍。两种类型都说明如下。

    Q: Can you predict how single and double replacement reactions differ?
    ::问题:你能预测单项和双倍替换反应如何不同吗?

    A: One way they differ is that a single replacement reaction involves one reactant compound, whereas a double replacement reaction involves two reactant compounds. Keep reading to learn more about these two types of reactions.
    ::A: 一种不同的方式是,单一的替代反应涉及一种反应化合物,而双重替代反应则涉及两种反应化合物。继续阅读以了解关于这两种反应的更多情况。

    Single Replacement Reactions
    ::单人更替反应

    A single replacement reaction occurs when one element replaces another in a single compound. This type of reaction has the general equation:
    ::当一个元素在单一化合物中替换另一个元素时,就发生单一重置反应。

    A + BC → B + AC

    In this equation, A represents a more reactive element and BC represents the original compound. During the reaction, A replaces B, forming the product compound AC and releasing the less reactive element B.
    ::在这个方程中, A 代表一个更具反应性的元素, BC 代表原化合物。 在反应中, A 取代 B, 形成产品丙烷化合物, 释放反应性较小的元素B。

    An example of a single replacement reaction occurs when potassium (K) reacts with water (H 2 O). A colorless compound named potassium hydroxide (KOH) forms, and hydrogen (H 2 ) is set free. The equation for the reaction is:
    ::例如,当钾(K)与水(H2O)发生反应时,就发生一种单一的替代反应,一种无色化合物,称为氢氧化钾(KOH)形式,氢(H2)。

    2K + 2H 2 O → 2KOH + H 2

    In this reaction, a potassium ion replaces one of the hydrogen atoms in each molecule of water. Potassium is a highly reactive group 1 alkali metal , so its reaction with water is explosive. 
    ::在这种反应中,钾离子取代了水中每个分子中的氢原子。钾是一种高度反应性的1类碱金属,因此它与水的反应是爆炸性的。

    Q: Find potassium in the periodic table of the elements. What other element might replace hydrogen in water in a similar replacement reaction?
    ::问题:在元素的周期表中查找钾。在类似的替代反应中,还有什么其他元素可以取代水中的氢?

    A: Another group 1 element, such as lithium or sodium, might be involved in a similar replacement reaction with water.
    ::A: 另一种第1组元素,如锂或钠,可能与水发生类似的替代反应。

    Double Replacement Reactions
    ::双重替换反应

    A double replacement reaction occurs when two ionic compounds exchange ions. This produces two new ionic compounds. A double replacement reaction can be represented by the general equation:
    ::当两个离子交换离子时发生双重替代反应,产生两种新的离子化合物。

    AB + CD → AD + CB

    AB and CD are the two reactant compounds, and AD and CB are the two product compounds that result from the reaction. During the reaction, the ions B and D change places.
    ::AB和CD是两种反应化合物,AD和CB是反应产生的两种产品化合物。 在反应中, 离子B和D改变位置。

    Q: Could the product compounds be DA and BC?
    ::问题:产品化合物能否是DA和BC?

    A: No, they could not. In an ionic compound, the positive metal ion is always written first, followed by the negative nonmetal ion. Therefore, A and C must always come first, followed by D or B.
    ::A:不,它们不能。在离子化合物中,正金属离子总是先写,然后写为负非金属离子。因此,A和C必须总是先写,然后写为D或B。

    An example of a double replacement reaction is sodium chloride (NaCl) reacting with silver fluoride (AgF). This reaction is represented by the equation:
    ::一种双重替代反应的一个例子是氯化钠(NaCl)与银氟化物(AgF)发生反应。

    NaCl + AgF → NaF + AgCl
    ::NaCl + AGF + NaF + AGCl

    During the reaction, chloride and fluoride ions change places, so two new compounds are formed in the products: sodium fluoride (NaF) and silver chloride (AgCl). 
    ::在反应过程中,氯化物和氟化物离子改变位置,因此产品中形成两种新的化合物:氟化钠和氯化银。

    Q: When iron sulfide (FeS) and hydrogen chloride (HCl) react together, a double replacement reaction occurs. What are the products of this reaction? What is the chemical equation for this reaction?
    ::问题:当硫化铁(FeS)和氯化氢(HCl)一起反应时,会发生双重替代反应。这种反应的产物是什么?这种反应的化学方程式是什么?

    A: The products of the reaction are iron chloride (FeCl 2 ) and hydrogen sulfide (H 2 S). The chemical equation for this reaction is:
    ::A:反应的产品是氯化铁(FeCl2)和硫化氢(H2S)。

    FeS + 2HCl → H 2 S + FeCl 2
    ::FES + 2HCl + H2S + FECl2

    Summary
    ::摘要

    • A replacement reaction occurs when elements switch places in compounds. This type of reaction involves ions. Generally, more reactive elements replace less reactive elements.
      ::当元素在化合物中切换位置时,即发生替代反应。这种反应涉及离子。一般而言,反应性较强的元素取代反应性较少的元素。
    • A single replacement reaction occurs when one element replaces another element in one compound. This type of reaction is represented by: A + BC → B + AC.
      ::当一个元素替换一个化合物中的另一个元素时,就出现单一的替代反应。这种反应有:A+ BC+ BC+ AC。
    • A double replacement reaction occurs when two ionic compounds exchange ions, producing two new ionic compounds. This type of reaction is represented by: AB + CD → AD + CB.
      ::产生两种新的离子化合物的两离子离子发生双重替代反应时,这种反应表现为:AB+CD AD+CB。

    Review
    ::回顾

    1. What is a replacement reaction?
      ::什么是替换反应?
    2. Compare and contrast single and double replacement reactions, and give the general equation for each type of reaction.
      ::比较和对比单项和双倍重置反应,并给出每种反应的总等式。
    3. Which of the following reactions is not a replacement reaction?
      1. Fe + CuSO 4 → FeSO 4 + Cu
        ::Fe + COSO4 + FESO4 + Cu
      2. 2Na + 2H 2 O → 2NaOH + H 2
        ::2Na + 2H2O + 2NaOH + H2
      3. Zn + 2HCl → ZnCl 2 + H 2
        ::Zn + 2HCl + ZnCl2 + H2
      4. 2Na + Cl 2 → 2NaCl
        ::2Na + Cl2 2NaCl

      ::下列反应中哪一种不是替代反应? Fe + CusO4 FESO4 + Cu 2Na + 2H2O + 2NaOH + H2 Zn + 2HCl + ZnCl2 + H2 2Na + Cl2 + 2NQl

    Resources
    ::资源