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  • General

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  • 化学反应和能源-先进

    Chemical reaction

    How do you change one thing into another?
    ::你怎么把一件事变成另一件事?

    The bonds between the atoms need to be rearranged. That is the definition of a chemical reaction . And all chemical sections need energy to get started.
    ::原子之间的关联需要重新排列。 这是化学反应的定义。 所有化学部分都需要能量才能启动 。

    Chemical Reactions and Energy
    ::化学反应和能源

    All chemical reactions involve energy. Some chemical reactions consume energy, whereas other chemical reactions release energy. Chemical reactions can be either spontaneous, which do not require an input of energy, or non-spontaneous, which does require an input of some type of energy. Energy may be in the form of heat, light or electricity. Each of the energy changes that occur during a reaction are graphed in Figure . In the reaction on the left, energy is released. In the reaction on the right, energy is consumed.
    ::一些化学反应消耗能量,而其他化学反应释放能量。化学反应可以是自发的,不需要投入能量,也可以是非自发的,确实需要投入某种能源。能源可以是热、光或电的形式。在反应过程中发生的每一种能量变化都用图示说明。在左边的反应中,能量是释放的。在右边的反应中,能量是消耗的。

    Exothermic and endothermic reactions
    The exothermic reaction on the left releases energy. The endothermic reaction on the right consumes energy.

    Thermodynamics
    ::热动力学

    Chemical reactions follow the laws of thermodynamics. The First Law of Thermodynamics states that energy can be changed from one form to another, but it cannot be created or destroyed. This law is also known as the Law of of Energy. The Second Law of Thermodynamics states the energy available after a chemical reaction is always less than that at the beginning of a reaction. This is also commonly referred to as entropy. Entropy can be described as the degree of disorder in a system . That is, as energy is transferred from one form to another, some of the energy is lost as heat, and the amount of available energy decreases. As the energy decreases, the disorder in the system increases, and, by definition, the entropy increases. Ice melting provides an example in which entropy increases. Entropy essentially is a measure of the tendency of a process, such as a chemical reaction, to proceed in a particular direction.
    ::化学反应遵循热力学的规律。 热力学的第一定律规定, 能量可以从一种形式改变为另一种形式, 但不能创造或销毁。 这部定律也称为能源法。 第二定律指出, 化学反应后的能量总是少于反应开始时的能量。 这通常也称为酶。 通制可以被描述为系统中的紊乱程度。 也就是说, 当能量从一种形式转移到另一种形式时, 一些能量会随着热量和可用能量的减少而消失。 随着能源的减少, 系统混乱会增加, 并且根据定义, 酶增加。 冰融化提供了一种能增加酶的示例。 共制熔基本上是一种过程趋势的衡量, 例如化学反应, 朝着一个特定的方向发展。

    Reactions can proceed by themselves if they are exergonic or exothermic, that is if they release energy. The associated free energy of the reaction is composed of two different thermodynamic quantities, enthalpy and entropy. Enthalpy is a measure of the total energy of a thermodynamic system. The change in enthalpy is positive in endothermic reactions, and negative in exothermic processes.
    ::反应可以自行进行,如果它们具有外热或外热作用,即释放能量。相关的反应自由能量由两种不同的热力量组成:和。酶是热力系统总能量的量度。除热反应中,的改变是积极的,在异热过程中是消极的。

    Exothermic Reactions
    ::异热反应

    Chemical reactions that release energy are called exothermic reactions . An example is the combustion of methane described at the beginning of this lesson. In organisms , exothermic reactions are called catabolic reactions . Catabolic reactions break down molecules into smaller units. An example is a decomposition reaction, such as the breakdown of glucose molecules for energy. Exothermic reactions can be represented by the general chemical equation :
    ::释放能量的化学反应被称为异温反应。 一个例子就是本课开头所描述的甲烷燃烧。 在生物体中,异温反应被称为同代反应。 异代反应将分子分解成小单元。 一个例子是分解反应, 如将葡萄糖分子分解为能量。 异热反应可以用一般化学方程式表示 :

    Reactants → Products + Heat.
    ::反应剂 + 产品 + 热。

    Endothermic Reactions
    ::内热反应

    Chemical reactions that consume energy are called endothermic reactions . Energy is usually absorbed from the surroundings as heat. An example is the synthesis of ammonia, described above. In organisms, endothermic reactions are called anabolic reactions . Anabolic reactions construct molecules from smaller units. An example is the synthesis of from amino acids . Endothermic reactions can be represented by the general chemical equation:
    ::消耗能量的化学反应被称为内温反应。能源通常作为热能从周围吸收。如上文所述氨的合成就是一个例子。在生物体中,内温反应称为代谢反应。代谢反应从较小单位中制造分子。氨基酸的合成就是一个例子。内温反应可以用一般化学方程式表示:

    Reactants + Heat → Products.
    ::反应剂+热量+产品。

    Ice Pack
    This pack gets cold due to an endothermic reaction.

    Endothermic Organisms
    ::地方体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体生物体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体体

    In biological systems, the term endothermic is a metabolic term related to the maintenance of body temperature. An endothermic is an organism that produces heat through internal means, a process known as . Animals may do this through muscle shivering or increasing metabolism . These animals absorb heat from their surroundings, so the term endothermic has distinct uses related to chemical reactions or maintenance of body temperature. The opposite of endothermy is ectothermy . Ectothermic animals ( cold-blooded ) do absorb heat from their surroundings.
    ::在生物系统中,端热一词是指与保持体温有关的代谢术语。端热系指通过内部手段产生热量的有机体,即所谓的过程。动物可以通过肌肉颤抖或增加新陈代谢来这样做。这些动物吸收周围的热量,因此,端热一词具有与化学反应或保持体温有关的不同用途。与端热相反的是切除。温热动物(冷血动物)的确吸收周围的热量。

    Summary
    ::摘要

    • Chemical reactions follow the laws of thermodynamics.
      ::化学反应遵循热动力学的定律。
    • Some chemical reactions are exothermic, which means they release energy. Other chemical reactions are endothermic, which means they consume energy.
      ::有些化学反应是过热的,这意味着它们释放出能量。其他化学反应是通热,这意味着它们消耗能量。
    • Catabolic and anabolic reactions occur in cells/organisms.
      ::在细胞/生物中发生代谢反应和新陈代谢反应。

    Review
    ::回顾

    1. Compare and contrast each of the following:
      1. The first and seconds laws of thermodynamics.
        ::热力学的第一和第二秒定律
      2. Entropy and enthalpy.
        ::和。
      3. Endothermic and exothermic reactions.
        ::局部热和体外热反应。
      4. Anabolic and catabolic reactions.
        ::新陈代谢和新陈代谢反应。

      ::温度动力学的一级和秒定律; 恒温和; 异温和异温反应; 新陈代谢和新陈代谢反应。