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  • General

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  • 能源

    Colorful fireworks explode in the night sky, creating vibrant patterns and lights.

    How do fireworks light up the sky?
    ::烟花如何点燃天空?

    The sight of fireworks exploding across the night sky is always exciting. These materials, invented hundreds of years ago, can be dangerous if not handled properly. The chemicals do not react until the fuse burns down and is applied to the system . Then the rocket is launched and explodes high in the sky.
    ::夜空的烟花爆炸景象总是令人兴奋的。 数百年前发明的这些材料如果处理不当,可能会很危险。 化学物质在引信燃烧并应用于系统之前不会发生反应。 然后火箭在天空中被发射和爆炸。

    Activation Energy
    ::能源

    Calcium metal chunks stored in a glass tube filled with argon gas.

    Calcium metal stored in an argon atmosphere.
    ::钙金属储存在方形大气中。

    Why do some occur readily while others require input of heat in order to take place? If we mix metallic sodium with water, a reaction occurs immediately, releasing a great deal of heat (enough to ignite the hydrogen that is formed). Group II , such as calcium, react at a much slower rate. Unlike the extremely vigorous reaction with sodium, the reaction with calcium is slow enough that we can trap the hydrogen gas released.
    ::为什么有些人会很容易发生,而其他人则需要热投入才能发生呢?如果我们把金属钠与水混合,就会立即发生反应,释放出大量的热量(足以点燃形成的氢气 ) 。 第二组,如钙,反应速度要慢得多。 与对钠的极强反应不同,对钙的反应速度太慢,我们可以捕捉释放的氢气。

    Supplying reactant particles with energy causes the bonds between the atoms to vibrate with a greater frequency. This increase in vibrational energy makes a more likely to break and a chemical reaction more likely to occur when those particles collide with other particles. The activation energy for a reaction is the minimum energy that colliding particles must have in order to undergo a reaction. Some reactions occur readily at room temperature because the reacting particles already have the requisite activation energy at that temperature. Other reactions only occur when heated because the particles do not have enough energy unless an external source of heat provides the particles with more .
    ::以能量提供反应粒子会导致原子与更频繁地振动之间的连接。 振动能量的增加使得这些粒子与其他粒子相撞时更有可能发生碎裂和化学反应。 反应的激活能量是相撞粒子必须具备的最小能量才能发生反应。 有些反应在室温下很容易发生, 因为反应粒子在温度下已经具备了所需的激活能量。 其他反应只有在加热时才会发生,因为粒子没有足够的能量,除非外部热源能为粒子提供更多能量。

     

     

    Summary
    ::摘要

    • Activation energy is defined for a chemical reaction.
      ::激活能量的定义是用于化学反应的。

    Review
    ::回顾

    1. Does sodium react faster or slower with water than calcium does?
      ::钠对水的反应是否比钙反应快或慢?
    2. How does vibrational energy contribute to a reaction?
      ::振动能量如何促成反应?
    3. Before some molecules react, what has to happen?
      ::在分子反应之前,必须发生什么?

    Explore More
    ::探索更多

    Use the  video below to answer the questions that follow.
    ::使用下面的视频回答下面的问题。

     

    1. Does magnesium react with water at room temperature?
      ::镁在室温下与水发生反应吗?
    2. How did the speaker get magnesium to react with water?
      ::扬声器如何得到镁 与水发生反应?
    3. How can you describe the reaction of Mg and H 2 O in terms of activation energy?
      ::您如何描述Mg和H2O在激活能量方面的反应?