Section outline

  • General

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  • 纯物质

    Moldy tomatoes in a container, indicating spoiled food and potential health risks.

    Have you ever had the experience of opening the refrigerator and seeing something you don’t recognize?
    ::你曾经有过打开冰箱 和看到一些你不认识的东西的经验吗?

    Not an unfamiliar food, but something that has changed over the time period it was in the refrigerator. You are not sure just what it is, so you call it “stuff.” Looking at it, you know it’s not a good idea to eat it, so you throw it out. If you’re not sure just what it is, you certainly don’t want to put it in your body.
    ::并不是不熟悉的食物,而是在冰箱里一段时间里发生变化的东西。 你并不确定它是什么,所以称之为“东西 ” 。 看着它,你知道吃它不是一个好主意,所以就把它扔掉。 如果你不确定它是什么,你肯定不想把它放在身体里。

    Substances
    ::物质物质

    Silver and ordinary table salt are two examples of chemical substances . A substance is matter that has a uniform and definite composition. All samples of substances, sometimes called pure substances, have identical properties. When chemists run a , they want to use pure materials so they know exactly what they are dealing with. They know that the reaction involves a specific substance, so they expect the same reaction to give the same results each time it is run.
    ::银盐和普通桌盐是化学物质的两个例子。一种物质是具有统一和确定成分的物质。所有物质样本,有时称为纯物质,都有相同的特性。当化学家运行一种物质时,他们想使用纯物质,以便知道他们正在处理的是什么。他们知道反应涉及一种特定物质,因此他们每运行一次都期望同样的反应产生同样的结果。

    One of the characteristics of a substance is that it cannot be separated into components by physical separation techniques. The acetylsalicylic (the active ingredient in aspirin) is a substance because it is a chemical compound that cannot be further reduced to other materials by physical means. However, the aspirin that contains the acetylsalicylic acid is a . In addition to the active pain-relieving ingredient, aspirin also may contain , corn starch, and cellulose, among other ingredients. These added materials bind the tablet components into a solid pill and influence how rapidly the material dissolves.
    ::一种物质的特性之一是,不能通过物理分离技术将其分离成组成部分。一种物质是乙酰硅(阿司匹林中的活性成分)是一种物质,因为它是一种化学化合物,不能通过物理手段进一步减少为其他物质;然而,含有乙酰硅酸的阿司匹林是一种物质。除了活性止痛成分外,阿司匹林还可能含有其他成分,包括玉米淀粉和纤维素。这些添加的材料将平板成分捆绑在一种固态药丸中,影响材料的迅速溶解。

    White aspirin tablets spill from a white bottle against a yellow background.
    Aspirin tablets.

    Substances may be either or pure compounds. They may also be solid, , or . Some of the elements (such as silver) exist in the solid form. Other elements (mercury) exist as liquids at room temperature . Elements such as helium and radon exist as gases at room temperature. A compound such as water will take the form of a solid, a liquid, or a gas, depending upon the temperature.
    ::物质可以是或纯的化合物,也可以是固体的,也可以是固体的,或者是.某些元素(如银)以固体的形式存在,其他元素(汞)作为液体存在于室温中,其他元素(汞)作为液体存在于室温中,例如和等元素作为气体存在于室温中,水等化合物的形式为固体、液体或气体,视温度而定。

    Summary
    ::摘要

    • A substance is a pure material with a uniform and definite composition.
      ::物质是一种纯物质,具有统一和明确的成分。
    • A substance cannot be separated into components using physical means.
      ::不能使用物理手段将物质分离成组成部分。
    • A substance can be a solid, a liquid, or a gas, depending on the temperature.
      ::物质可以是固体、液体或气体,视温度而定。

    Review
    ::回顾

    1. Define substance.
      ::界定实质内容。
    2. Can salt be a substance?
      ::盐能是一种物质吗?
    3. Is aspirin a substance?
      ::阿司匹林是一种物质吗?