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  • 分解反应反应

    A dark brown bottle of hydrogen peroxide used for disinfecting minor cuts and scrapes.

    Hydrogen peroxide is a widely used disinfectant for minor cuts and scrapes. You may have a bottle of hydrogen peroxide like the one pictured here in your medicine cabinet at home. Did you ever notice that hydrogen peroxide is always kept in a dark brown bottle like this one? Do you know why? The reason is that hydrogen peroxide needs to be protected from light. If it isn’t, it will gradually break down to water and oxygen. This is a .  
    ::氢过氧化氢是一种广泛使用的消毒剂,用于小切和刮痕。你可能有一瓶过氧化氢,就像你家的药柜里所描绘的一样。你有没有注意到过氧化氢总是被放在这种深褐色的瓶子里?你知道为什么吗?原因是过氧化氢需要保护不受光线影响。如果不是,它会逐渐分解为水和氧。这是一个问题。

    What Is A Decomposition Reaction?
    ::什么是分解反应?

    A decomposition reaction occurs when one reactant breaks down into two or more products. It can be represented by the general equation:
    ::当一个反应器分解成两个或两个以上产品时,就会发生分解反应。

    AB → A + B

    In this equation, AB represents the reactant that begins the reaction, and A and B represent the products of the reaction. The arrow shows the direction in which the reaction occurs.
    ::在这一方程式中,AB代表开始反应的反应物,A和B代表反应的产物。箭头显示反应的发生方向。

    Q: What is the chemical equation for the decomposition of hydrogen peroxide (H 2 O 2 ) to water (H 2 O) and oxygen (O 2 )?
    ::问题:将过氧化氢(H2O2)分解成水(H2O)和氧(O2)的化学方程是什么?

    A: The equation for this decomposition reaction is:
    ::A:这种分解反应的方程式是:

    2 H 2 O 2 → 2 H 2 O + O 2

    Other Examples of Decomposition Reactions
    ::其他分解反应实例

    Two more examples of decomposition reactions are described below. 
    ::下文将介绍另外两个分解反应的例子。

    • Carbonic (H 2 CO 3 ) is an ingredient in soft drinks. A decomposition reaction takes place when carbonic acid breaks down to produce water (H 2 O) and carbon dioxide (CO 2 ). This occurs when you open a can of soft drink and some of the carbon dioxide fizzes out. The equation for this reaction is:
      ::碳(H2CO3)是软饮料中的一种成分。当碳酸分解以产生水(H2O)和二氧化碳(CO2)时,就会发生分解反应。当打开一个软饮料罐和一些二氧化碳烟雾时,就会发生分解反应。这种反应的方程式是:
    H 2 CO 3 → H 2 O + CO 2
    • Another decomposition reaction occurs when water (H 2 O) breaks down to produce hydrogen (H 2 ) and oxygen (O 2 ) (see Figure ). This happens when an electric current passes through the water, as illustrated below. The equation for this reaction is:
      ::水(H2O)分解以产生氢(H2)和氧(O2)时,会出现另一种分解反应(见图)。
    2 H 2 O → 2 H 2 + O 2

    Water decomposition into hydrogen and oxygen gases using an electric current.

    Decomposition of water.
    ::水分分分解

    Q: What ratio of hydrogen molecules (H 2 ) to oxygen molecules (O 2 ) is produced in the decomposition of water?
    ::问题:水分分解过程中产生的氢分子(H2)与氧分子(O2)的比例是多少?

    A: Two hydrogen molecules per oxygen molecule are produced because water (H 2 O) has a ratio of two hydrogen atoms to one oxygen .
    ::A:每个氧分子产生两个氢分子,因为水(H2O)的氢原子与氧的比重是两个氢原子对一个氧。

    Summary
    ::摘要

    • A decomposition reaction occurs when one reactant breaks down into two or more products. This can be represented by the general equation: AB → A + B.
      ::当一个反应器分解成两个或两个以上产品时,就会发生分解反应,这可以用一般方程式表示:AB A + B。
    • Examples of decomposition reactions include the breakdown of hydrogen peroxide to water and oxygen, and the breakdown of water to hydrogen and oxygen.
      ::分解反应的例子包括将过氧化氢分解为水和氧,将水分解为氢和氧。

    Review
    ::回顾

    1. What is a decomposition reaction? What is the general equation for a decomposition reaction?
      ::什么是分解反应?分解反应的一般方程式是什么?
    2. Describe the decomposition of hydrogen peroxide, and write a balanced chemical equation for this reaction.
      ::描述过氧化氢的分解, 并写一个平衡的化学方程来进行这种反应 。
    3. Which of the following chemical equations represents a decomposition reaction?
      1. H 2 SO 3 → H 2 O + SO 2
        ::H2SO3 H2O + SO2
      2. 2Na + Cl 2 → 2NaCl
        ::2Na + Cl2 2NaCl
      3. 2K + 2H 2 O → 2KOH + H 2
        ::2K + 2H2O + 2KOH + H2
      4. NaCl + AgF → NaF + AgCl
        ::NaCl + AGF + NaF + AGCl

      ::下列哪些化学方程式代表分解反应? H2SO3 H2O + SO2 2Na + SO2 2Na + Cl2 + 2NaCl 2K + 2H2O + 2KOH + H2 NaCl + AGF + NaF + AGCl

    Explore More
    ::探索更多

    Watch the video about decomposition reactions, and then answer the questions below.
    ::观看关于分解反应的视频, 然后回答下面的问题。

     

     

    1. Why are decomposition reactions the opposite of synthesis reactions?
      ::为什么分解反应与综合反应相反?
    2. What are the products of the decomposition of hydrogen chloride (HCl)?
      ::氯化氢分解的产品是什么?
    3. What is missing from each of these balanced equations for decomposition reactions?
      1. 2Ni 2 O 3 → 4Ni + ?
        ::2N2O3 4Ni +?
      2. 2Al 2 O 3 → ? + 3O 2
        ::2 Al2O3 + 3O2 + 3O2

      ::每种分解反应的平衡方程式都缺少什么? 2Ni2O3 + 4Ni + +? 2Al2O3 + 3O2 + 3O2
    4. What is a general rule for the decomposition of metal hydrogen carbonates?
      ::金属氢碳酸盐分解的一般规则是什么?