化工专业英语第一片翻译.doc

Elements and Compounds 元素与化合物 Elements are pure substances that can not be decomposed(分解) into simpler substances by ordinary chemical changes. At present there are 109 known elements. Some common elements that are familiar to you are carbon, oxygen, aluminum, iron, copper, nitrogen, and gold. The elements are the building blocks of matter just as the numerals 0 through 9 are the building blocks for numbers. To the best of1 our knowledge, the elements that have been found on the earth also comprise(包含) the entire universe. 元素是单纯的物质，不能通过一般的化学变化分解成为更简单的物质。目前已知有109个元素。一些你熟悉的常见元素是碳、氧、铝、铁、氮和金。元素是组成物质的基本单元，就象0到9的数字是组成数的基本单元一样。就我们所知，已经在地球上发现的元素也是组成整个宇宙的元素。 About 85% of (85 percent of) the elements can be found in nature , usually combined with other elements in minerals and vegetable matter or in substances like water and carbon dioxide. Copper, silver, gold, and about 20 other elements can be found in highly pure forms. Sixteen elements are not found in nature; they have been produced in generally small amounts in nuclear explosions (爆炸)and nuclear research. They are man-made elements. 大约有85%的元素可以在大自然的矿物或者植物中，以及如水和二氧化碳这样的物质中找到，通常与别的元素结合。铜、银、金和别处约20%的元素可以在大自然中以高纯度的形式找到。有16种元素是不能在大自然中找到的，这些元素已经由核爆炸或者核研究中少量的制造出来，他们是人造元素。 Pure substances composed of1 two or more elements are called compounds. Because they contain two or more elements, compounds, unlike elements, are capable of being decomposed into simpler substances by chemical changes. The ultimate(最终的) chemical decomposition of compounds produces the elements from which they are made. 两种或者更多种元素结合成的单纯物质称为化合物。化合物与元素不同，由于其中含有两种或者更多种的元素，所以能够由化学变化分解成为更简单的物质。化合物化学分解的最终结果是生成组成该化合物的元素。 The atoms of the elements in a compound are combined in whole number ratio(以整数比), not in fractional parts(分数部分) of an atom. Atoms1 combined with one another to form compounds which exist as either molecule or ions. A molecule is a small, uncharged（不带电荷的） individual unit of a compound formed by the union of two or more atoms, if we subdivide（细分，再分） a drop of water into smaller and smaller particles, we ultimately(最终地) obtain a single unit of water known as a molecule of water. This water molecule consists of(由.组成) two hydrogen atoms and one oxygen atom bonded2(结合，键合) together. We cannot subdivide(再分;细分) this unit further without destroying the molecule, breaking it up into its elements. Thus, a water molecule is the smallest unit of the compound water. 不同元素的原子以整个数之比结合为化合物，而不是一个原子的一部分。一些原子与另一些其他原子结合成的化合物或者以分子存在，或者以离子存在。化合物中的一个分子是由两个或者更多的原子结合而成的很小且不带电荷的单元，当我们把一滴水分成越来越小的部分，我们最终得到一个称之为水分子的单元。这个水分子由结合在一起的两个氢原子和一个氧原子组成。我们不把这个水分子消灭，即破坏成为组成它的元素，就不能把它再分割。因而水分子是水这种化合物的最小单元。 An ion is a positive or negative electrically charged（电荷） atom or group of atoms. The ions in a compound are held together in a crystalline（晶体） structure by the attractive（吸引的） forces of their positive and negative charges. Compounds 1consisting of ions do not exist as molecules. Sodium chloride is an example of a non-molecular compound. Although this type of compound consists of large numbers of positive and negative ions, its formula（公式，分子式） is usually represented（描述；表现） by the simplest ratio of the atoms in the compound. Thus, the ratio of2 ions in sodium chloride is one sodium ion to one chlorine ion. 一个离子是带正电荷或者带负电荷的原子或者原子团。化合物中的离子靠正负电荷的吸引结合为晶体结构。由离子组成的化合物不以分子形式存在。氯化钠是非分子化合物的一个例子。尽管这种化合物由大量的正离子和负离子组成，但其分子式通常按这种化合物中不同原子的最简单的整数比表示。这样，氯化钠中钠离子与氯离子之比为一比一。 Compounds exist either as molecules which consist of two or more elements bonded together or in the form of1 positive and negitive ions held together by the attractive force of their positive and negative charges. 化合物或者以两个或更多的元素结合成为分子的形式存在，或者以正负离子靠正负电荷吸引力结合的形式存在。 The compound carbon monoxide (一氧化物) is composed of carbon and oxygen in the ratio of one atom of carbon to one atom of oxygen. Hydrogen chlorid contains a ratio of one atom of hydrogen to one atom of chlorine. Compounds（复数形式指多种化合物） may contain more than one atom of the same element. Methane (CH4)is composed of（由.组成） carbon and hydrogen in a ratio of one carbon atom to four hydrogen atoms; ordinary table sugar (sucrose C12H22O11) contains a ratio of 12 atoms of carbon to 22 atoms of hydrogen to 11 atoms of oxygen. These atoms are held together in the compound by chemical bonds. 一氧化碳是碳原子和氧原子按一比一组成.氯化氢含有的氢原子与氯原子之比是一比一。一些化合物的分子中同一元素的原子数可以多于一。甲烷由碳和氢组成，其碳原子与氢原子之比是1比4；食糖(蔗糖 C12H22O11)含有的碳、氢、氧原子数之比是12：22：11。化合物中的这些原子由化学键结合在一起。 There are over three million known compounds, with no end(没有尽头) in sight(看得见,在即,在望) as to the number that can and will be prepared(制备,准备) in the future. Each compound is unique(唯一的) and has characteristic(特有的) physical and chemical properties(性质). Let us consider in some detail two compoundswater and mercuric(汞,水银) oxide(氧化物). Water is a colorless, odorless, tasteless liquid that can be changed to a solid, ice at 0 and to a gas , steam(蒸汽) at 100. It is composed of two atoms of hydrogen(氢) and one atom of oxygen per molecule, which represents(表现) 11.2 percent hydrogen and 88.8 percent oxygen by mass. Water reacts chemically with sodium to produce hydrogen gas and sodium hydroxide(氢氧化物), with lime （calcareousness石灰） to produce calcium hydroxide, and with sulfur(硫) trioxide(三氧化物) to produce sulfuric(硫的,硫磺的) acid(酸). No other compound has all these exact(精确的) physical and chemical properties; they are characteristic of water alone. 已知的化合物超过3000000种，在今后还会制备出新的化合物，其种类还要增加。每一种化合物是唯一的（与其他的化合物有区别的）并且有他独特的物理和化学性质。让我们从某些具体内容来考察两种化合物水和氧化汞。水是无色、无嗅、无味的液体，在0下变成固体即冰，而在100变为气体即蒸汽。水的每个分子由一个氧原子和两个氢原子结合而成，氢和氧的质量百分数分别为11.2和88.8。水与钠反应生成氢气和氢氧化钠，与石灰反应生成氢氧化钙，与三氧化硫反应生成硫酸。其他的化合物不具有所有这些准确的物理和化学性质，这些性质是水特有的。 Mercuric oxide is a dense(致密的), orange-red powder composed of a ratio of one atom