In general,ethers are good solvents for fats,waxes and resins.醚通常是脂肪蜡和树脂的良好溶剂。
The gas from coke ovens is washed with water to remove ammonia.焦炉煤气用水洗涤可除去氨。
Hydrocarbons that do not contain the maximum number of hydrogen atoms possible are called unsaturated hydrocarbons.不含有最大可能氢原于数的烃叫不饱和烃。The functional group of a ketone consists of a carbon atom connected by a double bond to an oxygen atom．酮的官能团是由一个通过双键与氧原子相连的碳原子组成的。
When fuels burn,they return once more to the simple materials out of which they were made.燃料燃烧时，又转变成原来构成它们的那些简单的物质。
One may already have some idea of the material with which organic chemistry deals, but he may not know the extent to which organic chemistry touches on our life.也许有人已经对有机化学所涉及的物质有所了解，但是他可能并不知道有机化学触及我们日常生活已经达到什么样的程度。
A semiconductor is a material that is neither a good conductor nor a good insulator.半导体材料即不是良导体，也不是好的绝缘体。
Strength,hardness and plasticity of metals are the properties that make them so useful for industry.金属
的强度，硬度和可塑性等性能使得它们在工业上非常有用An acid is a compound whose solutions can produce hydrogen ions.酸是这样一种化合物，其溶液能产生氢离子。
The first higher homolog of benzene is toluene which is the raw material for the manufacture of the explosive.苯的第一个高级同系物是甲苯，它是制造的原料。
Comernicus,whose theory was not made public until after his death,believed that the sun was the center of the solar system.哥白尼认为太阳是太阳系的中心，但他的理论直到他死后才发表。
Live-wire operation is an advanced technique,by which wireman can repair transmission without cutting off the current.带电作业是一项先进技术，线路工人能不切断电流就修理输电线。
When the free electrons in a conductor move in one direction only,the current thus established is called a direct current,which is often abbreviated to DC.当导体的自由电子只以一个方向运动时，这样产生的电流叫直流电，常缩写为DC。
Iron is not as strong as steel which is an alloy of iron with some other element.铁的强度不如钢高，因为钢是铁和其他一些元素形成的合金。
The water should be free from dissolved salts which will cause deposits on the tubes and lead to overh
eating.水中应不含溶解盐，因为它会沉积在管壁上，导致过热。Copper,which is used to widely for carrying electricity,offers very little resistance.铜的电阻很小，所以广泛用来输电。
Molecules have perfect elasticity,in consequence of which they undergo no loss of energy after a collision.分子弹性很好，所以碰撞后并没有能量损失。
The workers oil the moving parts of these machines regularly,the friction of which may be greatly reduced.工人们定期给这些机器的传动部分加油，以便大大减小摩擦。
He wishes to write an article that will attract public attention to the matter.他想写一篇论文以期引起公众对这个问题的关注。
For any substance whose formula is known,a mass corresponding to the formula can be computed.不管什么物质，只要知道其分子式，就能求出与分子式相应的质量。Alloys,which contains a magnetic substance,generally also have a magnetic properities.金属如果含有磁性物质，一般也会具有磁性。
Photographs are taken of stars,the light of which is too faint to be seen by eyes at all.虽然很多星体的光线非常微弱眼睛根本看不到，但它们的照片还是可被拍下来的。Water,the temperature of which reaches100℃,begins to boil.当水的温度达到100℃时，开始沸腾。
Electricity which is passed through the thin tungsten wire inside the bulb makes the wire very hot.电通过灯泡里的钨丝时，会使钨丝变热。
Objectionable hydrogen sulfide is removed from such a gas or from naturally occurring hydrocarbon gases by washing with various alkaline solutions in which it is absorbed.要从这样的煤气或天然存在的烃类气体中除去有害物质硫化氢，就要用能吸收硫化氢的各种碱性溶液来洗涤。
Gas absorption is an operation in which a gas mixture is contacted with a liquid for the purposes of preferentially dissolving one or more components of the gas and to provide a solution of these in the liquid.气体吸收是这样一种操作：让气体混合物与液体接触，以使气体中的一种或多种组分优先溶解在液体中，并提供由这些组分和液体所形成的溶液。
There have been opened up to the vast and excellent science，in which my work is the beginning,ways and means by which other minds more acute than mine will explore its remote corners.通往伟大而美好科学的途径和手段已经展现在眼前。在科学领域中，我的研究只是个开端，比我敏锐的其他人所采用的途径和手段将会探索科学领域的遥远境地。
The continuous process although requiring more carefully designed equipment than the batch process,can ordinarily be handled in less space,fits in with other continuous steps more smoothly,and
can be conducted at any prevailing pressure without release to atmospheric pressure.虽然连续过程比间歇过程要求更为周密设计的设备，但连续过程通常能节约操作空间，较顺利地适应其它连续操作步骤，并能在任何常用的压力下进行，而不必暴露在大气中。
How these two things—energy and matter—behave,how they interact one with the other,and how people control them to serve themselves make up the substance of two basic physical sciences,physics and chemistry.能量和物质这两样东西具有什么样的性质，如何相互起作用，如何控制它们为人类服务，这些问题就构成了物理和化学两门基础自然科学的主要内容。
This simple fact shows that the more of the force of friction is got rid of,the further will the ball travel,and we are led to infer that,if all the impeding force of gravitation could be removed,there is no reason why the ball,once in motion,should ever stop.
这一简单事实表明，摩擦力越小，球会滚得越远。由此我们可以推论，如果把对引力起着阻碍作用的一切阻力排除掉，那么曾经处于运动状态的球就没有理由会再停下来了。
This is why the hot water system in a furnace will operate without the use of a water
pump,if the pipes are arranged so that the hottest water rises while the coldest water runs down again
to the furnace.如果把管子装成这个样子，使最热的水上升，而最冷的水再往下回流到锅炉里去，那么，锅炉中的热水系统不用水泵就能循环，道理就在于此。
The diode consists of a tungsten filament,which gives off electrons when it is heated, and a plate toward which the electrons migrate when the field is in the right direction.二极管由一根钨丝和一块极板组成：钨丝受热时便放出电子，当电场方向为正时，这些电子便向极板移动。
Fire is a chemical reaction in which atoms of the gas oxygen combine with atoms of certain other elements,such as hydrogen or carbon.燃烧是一种化学反应，在这个反应中，气体氧的原子与某些其他元素的原子，如氢或碳，相化合。Manufacturing process may be classified as unit production with small quantities being made and mass production with large numbers of identical parts being produced.制造过程可分为单件生产和大量生产。单件生产就是生产少量的零件，大量生产就是生产大批相同的零件。
Another development,by itself not strictly scientific in nature,is the growing awareness that the energy resources at present available to human technology are limited,and that photosynthesis is the only large-scale process on earth by which a virtually inexhaustible source of ,the radiation energy of the sun,is collected and converted into a form of energy that is not only used by plants,but b
y all forms of life,including man.另一发展——就其本性而言，本身不是严格科学的——是人们正日益认识到下面这个事实，即：人类技术领域目前可以利用的能源是有限的，在地球上只有光合作用是能将那实际上是取之不尽用之不竭的能源——太阳的辐射能——聚集起来，转换为不仅植物，而且包括人在内的所有生命都可以利用的能量形式的大规模过程。
Surfactants(表面活性剂)are substances that increase the solubility(溶解度)of one substance in another.Soaps and detergents(洗涤剂)are common surfactants that enable nonpolar(非极性)substances like oil and grease(油脂)to be emulsified(乳化) and washed away with the polar solvent water.From our everyday experiences,we know that oil and water do not mix,that is they are insoluble in each other.They are insoluble in each other because oil is nonpolar and water is polar and the rule of thumb(经验法则)for solubility is“like dissolves(溶解)like”.In other words,polar solvents(溶剂)dissolve polar solutes(溶质),and nonpolar solvents dissolve nonpolar solutes.A surfactant is a molecule that contains a polar portion and a nonpolar portion.By having both polar and nonpolar groups within the same molecule,a surfactant can interact with both polar and nonpolar molecules,thereby increasing the solubility of two otherwise insoluble subatance.表面活性剂能够提高一种物质在另外一种物质中的溶解度。肥皂和洗涤剂是最为普遍的表面活性剂，它们能够使类似油和油脂等非极性物质乳化从而可以随着极性的水溶剂洗去。从我们的日常经验来看，我们知道油和水不能互相混合，这是因为它们不互溶。
它们只所以不互溶，是因为油是非极性的而水是极性的，根据溶解的“相似相溶”经验法则二者不互溶。换句话说，极性溶质溶于极性溶剂，非极性溶质溶于非极性溶剂。表面活性剂是一种既含有极性部分也含有非极性部分的物质。因为在表面活性剂分子中同时含有极性和非极性部分，所以它可以同时和极性和非极性分子作用，
reaction to a book or an article因此可以提高在不溶物质的溶解度。
The versatility of chemical engineering originates in training to the practice of breaking up a complex process into individual physical steps,called unit operations, and into the chemical reactions.化学工程的多功能性源于把复杂的过程分解为独立的物理步骤（单元操作）以及化学反应的实践中。
Designs which avoid the need for hazardous materials,or use less of them,or use them at lower temperatures and pressures,or dilute them with inert materials will be inherently safe and not require elaborate safety systems.设计本身应该是安全的，但无需追求完美的安全系统。应尽量避免使用或减少危险的原料的用量，或在较低温度和压力条件下使用，或用惰性材料稀释。
It is important that engineers have an understanding of the physical laws governing these transport processes if they are to understand what is taking place in engineering equipment and to make wise decisions with regard to its economical operation.如果工程师想搞清楚机械设备中发生了什么并在操作
过程做出明智的选择，那么他们掌握这些决定传递过程的物理定律就显得非常重要的。

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