Cuon Sach Hoan Hao Ve Ngon Ngu Co The - Ebook download as PDF File .pdf) or read book online. Ngon ngu co bestthing.info - Free ebook download as PDF File .pdf) or read book online for free. 28 Tháng Năm (Nếu 2 link trên đều die thì bạn vào bestthing.info gõ "Cuốn sách hoàn hảo về ngôn ngữ cơ thể free ebook download" sẽ có rất nhiều link down.
|Language:||English, French, Dutch|
|Genre:||Politics & Laws|
|ePub File Size:||22.41 MB|
|PDF File Size:||15.69 MB|
|Distribution:||Free* [*Sign up for free]|
AND BIOLOGICAL TECHNOLOGY IN ENGLISH (NGÔN NGỮ TIẾNG ANH Cùng với mỗi bài khóa có bài luyện và ôn ngữ pháp cơ bản, như vậy sinh viên học . Hóa học công nghiệp quan tâm đến gì? bestthing.info 8 UNIT 2 . Ngôn ngữ cơ thể (Body language) (); Các tín hiệu (Signals) (); Ngôn ngữ trao đổi (Talk Language) (, cùng với Allan Garner); Ngôn ngữ viết ( Write. Việc mất khả năng giao tiếp có thể là một trong những vấn đề gây bực bội và khó 55% là ngôn ngữ cử chỉ, tức là thông điệp mà chúng ta đưa ra bằng sự biểu.
UNIT 9: The equipment of a chemical laboratory varies according to the nature of the work, which is to be carried out.
Every chemical laboratory should be provided with running water, gas and electricity. The water supply is conducted from the mains by means of pipes, the piping terminating in taps under, which there are sinks to take away waste water and other non-objectionable liquids.
When one needs water one turns the tap on and stops it flowing by turning the tap off. Similarly a system of pipes is attached to the gas main from where gas reaches the various kinds of burners.
Cuon Sach Hoan Hao Ve Ngon Ngu Co The
They serve for producing flames of different intensity, the Bunsen burner being the most common type used. Apart from a gas supply there is electricity which serves for lighting and as a driving power. For operating electricity, switches or switch buttons are employed.
That is why we talk about switching on the light or switching it off. One of them, a desiccator, is used for drying materials. Ovens, furnaces or kilns serve for generating high temperatures.
Where harmful vapors and undesirable odorous develop during the operation, a hood with suitable ventilation has to be provided for their escape. Of primary importance are glass and porcelain vessels. Glass vessels for chemical processes are made of special materials. They have to resist sudden changes in temperature, to withstand very high temperature: The necessary assortment of laboratory glassware includes test tubes, beakers, various flasks, watch glasses, funnels, bottles, and cylinders.
Porcelain articles consist of various kinds of dishes, basins and crucibles of various diameters. A grinding mortar with a pestle, desiccating dishes and stirrers are also generally made of porcelain.
Containers made of them are especially suitable for storing stock solutions. The analytical balance, which is used for accurate weighing of samples, is usually kept in a separate room.
Read and translate into Vietnamese indispensable, research, institute, confirm, demonstrate, phenomena, industry, application, science, equipment, vary, theoretical, technician, technologist, verify, employ, scientist, scientific, electricity, terminate, attached, burner, intensity, power, powder, equipped, variety, desiccator, oven, furnaces, generate, porcelain, refractory, assortment, cylinder, basin, crucible, pestle, stirrer, increase, resistant, unbreakable, analytical, balance, polyethylene.
What is the task of laboratory work? Why is it important and necessary for you as students of chemistry to make experiments in your school laboratories? Describe the general equipment of chemical laboratories. Which properties should the glass be used for making chemical vessels possess? What does the necessary assortment of laboratory glassware include? What do porcelain articles usually consist of? What are the advantages of polyethylene bottles? What are containers made of plastic materials especially suitable for?
What do burners serve for? What is the analytical balance used for? Elements already known retained their old names, e. The names of compounds are formed from those of their components so as to indicate their composition. When a metal forms two compounds with oxygen, the two oxides are distinguished by adding -ous and -ic to the Latin name of the metal, signifying the lower and higher oxidation states respectively, e. The salts corresponding to cuprous oxide are called cuprous salts, e.
Another way of distinguishing between different compounds of the same element is by the use of the Greek prefixes to the names of the elements.
These prefixes are as follows: To these we may add the Latin hemi-, meaning one half, and sesqui-, meaning one and a half, and per-. By the use of these prefixes we can designate the compounds more precisely than by means of the prefixes -ous and -ic, especially when more than two compounds exist.
Oxides, which form salts with acids, are known as basic oxides; by combination with water, basic oxides form bases. H2O are ferrous hydroxide and ferric hydroxide, respectively. The endings -ous, -ic are also applied to acids, the -ous acid containing less oxygen than the -ic acid, e. Salts are named in relation to the acids from which they are derived according to the following rules: Accordingly, salts of sulfurous acid are called sulfites, those of sulfuric acid, sulfates.
Salts of phosphorous acid are phosphites, of phosphoric acid, phosphates, etc. Read and translate into Vietnamese nomenclature, devised, binary, sodium chloride, respectively, designate, basic, bases, hydroxyl, formulas, salt, corresponding, sodium chlorite, cuprous oxide, cupric oxide, sodium chlorate, involve. When was the systematic chemical Nomenclature devised and what is the difference between the names of elements already known at that time and the names of newly discovered elements?
How are the names of compounds formed? What are the endings -ous, -ic used for and what is the difference between them? When are the Greek prefixes mono-, di-, tri-, etc.
What are the rules for forming the names of salts? Certainly, all our natural rivers and lakes and even the water stored in most reservoirs may be subjected to pollution, and generally cannot be considered safe for drinking purposes without some forms of treatment.
The type and extent of treatment will vary from city to city, depending upon the conditions of the raw water. Treatment may comprise various processes used separately or in combinations, such as storage, aeration, sedimentation, coagulation, rapid or slow sand filtration, and chlorination, or other accepted forms of disinfection.
When surface waters serve as a municipal water supply, it is generally necessary to remove suspended solid, which can be accomplished either by plain sedimentation or sedimentation following the addition of coagulating chemicals. In the water from most streams that are suitable as a source of supply, the sediment is principally inorganic, consisting of particles of sand and clay and small amount of organic matter.
In this water there will also be varying numbers of bacteria, depending upon the amount of bacteria nutrients, coming from sewage or other sources of organic matter, and upon the prevailing temperature. Many of the bacteria may have come from the soil and, as a result, during a season of high turbidity when there is a large amount of eroded soil in the water, the bacterial count from this source may be relatively high.
If the organisms are derived from sewage pollution, the number will be highest during periods of low flow when there is less dilution, and at this time the turbidity will, in general, be low. The amount of sediment may vary a great deal from one river to another, depending upon the geological character of the various parts of the drainage system.
The size of the suspended particles can also vary greatly.
In some waters the clay particles may be extremely fine, in fact, they may be smaller than bacteria. The time required for satisfactory sedimentation differs for different waters, and generally must be established by actual experiments.
Some waters can be clarified satisfactorily in a few days, while others may require weeks or months. As far as total weight of sediment is concerned, the bulk of it is probably removed in a few days, but this may not bring about a corresponding change in the appearance of the water, since the smaller particles may have greater influence than the large ones upon the apparent color and turbidity.
When plain sedimentation is used primarily as a preliminary treatment, a high degree of clarification is not needed and, as a result, shorter periods of settling are adequate.
After flocculation treatment, water is passed through beds of sand with diatomaceous earth to accomplish sand filtration. As we mentioned previously, some protozoan cysts, such as those of G. The microorganisms are trapped mostly by surface adsorption in the sand beds.
They do not penetrate the tortuous routing of the sand beds, even through the openings might be larger than the organisms that are filtered out. These sand filters are periodically backflushed to clear them of accumulations.
Water systems of cities that have an exceptional concern for toxic chemicals supplement sand filtration with filters of activated charcoal carbon. Charcoal has the advantage of removing not only particulate matter but also some dissolved organic chemical pollutants. Before entering the municipal distribution system, the filtered water is chlorinated. Because organic matter neutralized chlorine, the plant operators must pay constant attention to maintaining effective levels of chlorine.
There has been some concern that chlorine itself might be a health hazard, that it might react with organic contaminants of the water to form carcinogenic compounds. At present, this possibility is considered minor when compared with the proven usefulness of chlorination of water. One substitute for chlorination is ozone treatment.
Ozone O3 is a highly reactive form of oxygen that is formed by electrical spark discharges and ultraviolet light. The fresh odor of air following an electrical storm or around an ultraviolet light bulb is from ozone.
Ozone for water treatment is generated electrically at the site of treatment. Use of ultraviolet light is also a possible alternative to chemical disinfection. Arrays of ultraviolet tube lamps are arranged in quartz tubes so that water flows close to the lamps. This is necessary because of the low penetrating power of ultraviolet radiation. Read and translate into Vietnamese treatment, combination, storage, aeration, sedimentation, coagulation, chlorination, disinfection, bacterium, nutrients, sewage, pollution, beds of sand, drainage, influence, turbidity, diatomaceous earth, accumulation, activated carbon.
What are the various processes for water treatment? What is the method for removing the suspended solids from surface waters? What are the principal sediments from water of streams? What are the methods for trapping the microorganisms from various kinds of water? What is the purpose of chlorination of water? What is the substitute for chlorination of water? What is the kind of physical agent for water treatment of microorganisms in Vietnam? Say a few words about the water treatment in Vietnam.
UNIT It should have a number of accessories in order to operate satisfactorily. First of all it generally must be closed, except for a vent, in order to prevent loss of material and danger to the operating personnel.
For reactions carried out under pressure the vent is replaced by a safety valve. High-pressure conditions frequently introduce complications in the design and greatly increase the initial cost. For example, the top closure must be able to withstand the same maximum pressure as the rest of the autoclave. At medium pressures a satisfactory closure can be assembled. It is usually necessary to agitate the reaction mixture in batch systems.
This can be done mechanically with stirrers operated by a shaft extending through the reactor wall. Provision for heating or cooling the reaction contents is often required. This may be accomplished by circulating a fluid through a jacket surrounding the reactor.
Where heat effects are large enough to require the most rapid heat transfer, the jacket may be augmented by heating or cooling coils immersed in the reaction mixture. Flow reactors. Flow reactors may be constructed in a number of ways. The conventional thermal- cracking units in the petroleum industry are examples of a noncatalytic type.
The gas oil or other petroleum fraction is passed through a number of alloy-steel tubes placed in a series on the walls and roof of the furnace. On the other hand, flow reactors may consist of a tank or kettle, much like a batch reactor, with provision for continuously adding reactants and withdraw product.
From a design viewpoint the essential difference between tubular and tank reactors lies in the degree of mixing obtained. In the tubular type, where the length is generally large with respect to the tube diameter, the forced velocity in the direction of flow is sufficient to retard mixing in the axial direction.
On the other hand, in tank reactors, it is possible to obtain essentially complete mixing by mechanical agitation. Under these conditions the composition, temperature and pressure are uniform through the vessel. Read and translate into Vietnamese kettle, tank, accessories, autoclave, agitate, mixture, stirrers, circulating, jacket, coils, petroleum, roof, furnace, endothermic, batch reactor, tubular, velocity http: What are the various kind of batch reactors?
Why must the batch reactors be closed? Why does the top closure of batch reactors have to be installed with the vent or the safety valve? What is the purpose of a jacket surrounding the reactor? Tell something about the flow reactor? It is common practice, however, to regard it as consisting of two parts: Chemicals of this type are chiefly used in the manufacture of other products and do not ordinarily take the form of familiar household products or articles of commerce.
The chemical-process industry is even more dependent upon classifications of an arbitrary nature, and hence its scope is correspondingly more open to differences of opinion. According to the most widely accepted definition, the chemical-process industry consist of the companies which manufacture such products as drug, soap, paint, fertilizers, vegetable and animal oils, and a number of various related products.
Contrary to more technically based definitions, however, this classification excludes companies engaged in the production of iron and steel, in petroleum refining, and in the manufacture of pulp and paper, rubber products, leather products and glass.
Their exclusion has probably been due primarily to the combination of their origin, large size, simple product structure, and well-defined markets. Hence, it has long been the custom of economists and statisticians to regard them as independent industries. As matter of fact, both the oil industry and the steel industry were, until comparatively recently, much larger in size than the chemical industry as officially defined. Regardless of the arbitrary limitations of its official definition, however, the chemical industry has been steadily expanding.
It has ignored industrial boundaries in the application of new manufacturing processes and in the development of new products. The already existing chemical companies have entered new industries, such as textiles, building materials, and drugs.
And industries not recognized as chemical in nature have begun the manufacture of chemical products by new methods from new materials. A recent and conspicuous example of this latter type of chemical expansion has been the development of the so-called "petrochemical industry", in which chemical products are manufactured from petroleum raw materials.
Read and translate into Vietnamese http: Is there any sharply defined frontier between the chemical industry and many other industries? Can you give some concepts about the chemical-product industry? Can you tell something about the chemical-process industry? Has the chemical industry been steadily expanding and how? Can you give some concepts of "petro-chemical industry"? This illustrates the fact that a raw materials referred to here are those which become a part of the finished product itself or are used directly in manufacturing operations.
As has been indicated, this classification includes 1. In the chemical industry the segregation between semifinished and finished product is particularly difficult, since many chemical products are not only sold as such but are also consumed in the manufacture of other end products.
However, a material cannot be classified in two categories within a company, and one or the other must be selected. Usually, decision is influenced by the fact that more of the material is sold than consumed, or vice versa.
If more is consumed, and then the material becomes a semifinished product; if more is sold, the material is classified as finished product. Read and translate into Vietnamese inventory, materials, semifinished, products, raw materials, salable, prefabrication, illustrate, manufacture, perform, segregation, selected, category, influenced, consumed. What are the inventories? Can you tell something about inventories? What are raw materials? Give an example.
What are processed materials? Can you tell the difference between semifinished and finished products? All scientists have the obligation to prepare written reports of the results of experimental work. Since this record may be studied by many individuals, it must be completed in a clear, concise and accurate manner.
This means that procedural detail, observations and results must be recorded in a laboratory notebook while the experiment is being performed. The notebook should be hardbound with quadrille-ruled gridded pages and used only for the biochemistry laboratory.
This provides a durable, permanent record and the potential for construction of graphs, charts, etc. It is recommended that the first one or two pages of the notebook be used for a constantly updated table of contents. Although your instructor may have his or her own rules for preparation of the notebook, the most readable notebooks are those in which only the right - hand pages are used for record keeping.
The left - hand pages may be used for your own notes, reminders and calculations. If a new technique or instrumental method is introduced, give a brief description of the method. Include chemical or biochemical reactions when appropriate. Experimental Begin this section with a list of all reagents and materials used in the experiment. The sources of all chemical and the concentrations of solutions should be listed. Instrumentation is listed with reference to company name and model number. A flowchart to describe the stepwise procedure for the experiment should be included after the list of equipment.
Experimental a Table of materials and reagents b List of equipment c Flowchart d Record of procedure Data and Calculations a Record of all raw data b Method of calculation with statistical analysis c Enter data in tables, graphs or figures when appropriate For the early experiments, a flowchart is provided.
Flowcharts for later experiments should be designed by the student. The write-up to this point is to be completed as a Prelab assignment. The experimental procedure followed is then recorded in your notebook as you proceed through the experiment. The detail should be sufficient so that a fellow student can use your notebook as a guide.
You should include observations, such as color changes or gas evolution, made during the experiment. Data and Calculations All raw data from the experiment are to be recorded directly in your notebook, not on separate sheets of paper. Calculations involving the data must be included for at least one series of measurements. Proper statistical analysis must be included in this section. The Analysis of Results section following each experimental procedure in this book describes the preparation of graphs and tables.
These must all be included in your notebook. Results and Discussion This is the most important section of your write-up, because it answers the questions:. Any conclusion that you make must be supported by experimental results. It is often possible to compare your data with known values and results from the literature. If this is feasible, calculate percentage error and explain any differences. Note if any problems were encountered in the experiments. All library references books and journal articles that were used to write up the experiment should be listed at the end.
The standard format to follow for a book or journal listing is shown at the end of this chapter in the reference section. Everyone has his or her own writing style, some better than others.
It is imperative that you continually try to improve your writing skills. When your instructor reviews your write-up, he or she should include helpful writing tips in the grading.
Read and translate into Vietnamese experience, obligation, observation, notebook, statement, goals, discussion, description, biochemistry, material, instrumentation, flowchart, stepwise, measurement, presentation, significance B. What is the laboratory notebook?
How many steps are there in experimental write-up? What is the first section of experimental write-up? Tell something about it? Say a few words about calculations of experimental works?
Why should we need discussion of experimental results? The interaction of atoms and molecules is called chemistry. The metabolic activities of microorganisms involve complex chemical reactions.
Nutrients are broken down by microbes to obtain energy and to make new cells. Structure of Atoms 1. Atoms are the smallest units of chemical elements that enter into chemical reactions. Atoms consist of a nucleus, which contains protons and neutrons and electrons that move around the nucleus. The atomic number is the number of protons in the nucleus: Chemical Elements 1.
Atoms with the same atomic number and same chemical behavior are classified as the same chemical element. Chemical elements are designated by letter abbreviations called chemical symbols. There are about 26 elements commonly found in living cells. Atoms that have the same atomic number are of the same element but different atomic weights are called isotopes. In an atom, electrons are arranged around the nucleus in electron shells.
Each shell can hold a characteristic maximum number of electrons. The chemical properties of an atom are largely due to the number of electrons in its outermost shell. Molecules are made up of two or more atoms; molecules consisting of at least two different kinds of atoms are called compounds. Atoms form molecules in order to fill their outermost electron shells. Attractive forces that bind the atomic nuclei of two atoms together are called chemical bonds. The combining capacity of an atom - the number of chemical bonds the atom can form with other atoms - is its valence.
Ionic Bonds 1. A positively or negatively charged atom or group of atoms is called an ion. A chemical attraction between ions of opposite charge is called an ionic bond.
To form an ionic bond, one ion is an electron donor; the other ion is an electron acceptor. Covalent Bonds 1. In a covalent bond, atoms share pairs of electrons.
Covalent bonds are stronger than ionic bonds and are far more common in organisms. Hydrogen Bonds 1. A hydrogen bond exists when a hydrogen atom covalently bonded to one oxygen or nitrogen atom is attracted to another oxygen or nitrogen atom. Hydrogen bonds form weak links between different molecules or between parts of the same large molecule.
Molecular Weight and Moles 1. The molecular weight is the sum of the atomic weights of all the atoms in a molecule. A mole of an atom, ion, or molecule is equal to its atomic or molecular weight expressed in grams.
47. Ngon ngu co the.pdf
The number of moles of a substance equals its mass in grams divided by its molecular weight. Chemical Reactions Chemical reactions are the making or breaking of chemical bonds between atoms.
Energy of Chemical Reactions 1. A change of energy occurs during chemical reactions. Endergonic reactions require energy, exergonic reactions release energy. In a synthesis reaction, atoms, ions, or molecules are combined to form a large molecule. In a decomposition reaction, a large molecule is broken down into its component molecules, atoms, and ions. In an exchange reaction, two molecules are decomposed, and their subunits are used to synthesize two new molecules. The products of reversible reactions can readily revert back to form the original reactants.
How Chemical Reactions Occur 1. For a chemical reaction to take place, the reactants must collide with each other. The minimum energy of collision that can produce a chemical reaction is called its activation energy.
Specialized proteins called enzymes accelerate chemical reactions in living systems by lowering the activation energy. Read and translate into Vietnamese interaction, metabolic, microorganisms, complex, nutrients, microbes, cells, behavior, symbol, properties, valence, covalent, attractive, attraction, express, subunits, collide, collision, activation energy, protein, enzymes B. What is the atom? Say some words about chemical elements.
Say something about chemical bonds. How do the chemical reactions occur? How many kinds of chemical reactions do you know? What are they? Sewage includes all the water from a household that is used for washing as well as toilet wastes. Rainwater flowing into street drains and some industrial wastes enter the sewage systems in some cities. Sewage is mostly water and contains little particulate matter perhaps only about 0.
Even so, in large cities, this solid portion of sewage can total more than tons of solid material per day. Until environmental awareness intensified, a surprising number of large cities in which had only rudimentary sewage treatment systems or no system at all.
Raw sewage, untreated or nearly so, was simply discharged into rivers or oceans. A flowing, well-aerated stream is capable of considerable self- purification.
Therefore, until increases in populations and their wastes exceeded this capability, casual treatment of municipal wastes caused little complaint. In the United States, most methods of simple discharge have been improved. Primary Treatment The usual first step in sewage treatment is called primary treatment.
In this process, incoming sewage receives preliminary treatment - large floating materials are screened out, the sewage is allowed to flow through settling chambers so that sand and similarly gritty material can be removed, skimmers remove floating oil and grease, and floating debris are shredded and ground.
After this step, the sewage passes through sedimentation tanks, where solid matter settles out. The design of these primaries settling - tanks varies. Sewage solids collecting on the bottom are called sludge; sludge at this stage is called primary sludge.
Biological activity is not particularly important in primary treatment, although some digestion of sludge and dissolved organic matter can occur during long holding times. The sludge is removed on either a continuous or an intermittent basis, and the effluent the liquid flowing out then undergoes secondary treatment.
An important concept in sewage treatment and in the general ecology of waste treatment, BOD is a measure of the biologically degradable organic matter in water. BOD is determined by the amount of oxygen required by bacteria to metabolize the organic matter.
The classic method of measurement is to use special bottles with airtight stoppers. Each bottle is first filled with the test water or dilutions of the test water.
The water is initially aerated to provide a relatively high level of dissolved oxygen and is seeded with bacteria if necessary.
The filled bottles are then incubated in the dark for five days at 20oC, and the decrease in dissolved oxygen is determined by a chemical or electronic testing method. The more oxygen that is used up as the bacteria degrade the organic matter in the sample, the greater the BOD - which is usually expressed in milligrams of oxygen per liter of water.
Typical BOD values of waste water may be twenty times this amount. If this waste water enters a lake, for example, bacteria in the lake begin to consume the organic matter responsible for the high BOD, rapidly depleting the oxygen in the lake water.
Secondary Treatment After primary treatment, the great part of the BOD remaining in the sewage is in the form of dissolved organic matter. Secondary treatment, which is primarily biological, is designed to remove most of this organic matter and reduce the BOD. In this process, the sewage undergoes strong aeration to encourage the growth of aerobic bacteria and other microorganisms that oxidize the dissolved organic matter to carbon dioxide and water.
Two commonly used methods of secondary treatment are activated sludge systems and trickling filters. In the aeration tanks of the activated sludge system, air or pure oxygen is added to the effluent from primary treatment. The sludge in the effluent contains large numbers of metabolizing bacteria, together with yeasts, molds, and protozoans.
An especially important ingredient of the sludge are species of Zoogloans and bacteria, which form flocculent masses flocs in the aeration tanks. The activity of these aerobic microorganisms oxidizes much of the effluent's organic matter into carbon dioxide and water. When the aeration phase is completed, the floc secondary sludge is allowed to settle to the bottom, just as the primary sludge settles in primary treatment.
Soluble organic matter in the sewage is adsorbed onto the floc and is incorporated into microorganisms in the floc. As the floc settles out, this organic matter is removed with the floc and is subsequently treated in an anaerobic sludge digester.
More organic matter is probably removed by this process than by the relatively short-term aerobic oxidation. Most of the settled sludge is removed from the digester; some of the sludge is recycled to the activated sludge tanks as a starter culture for the next sewage batch. The effluent water is sent on for final treatment.
Occasionally, when aeration is stopped, the sludge will float rather than settle out; this phenomenon is called bulking. When this happens, the organic matter in the floc flows out with the discharged effluent and often causes serious problems of local pollution. A considerable amount of research has been devoted to the causes of bulking and its possible prevention.
It is apparently caused by the growth of filamentous bacteria of various types; the sheathed bacteria Sphaerotilus natans is often mentioned as the primary offender. Activated sludge systems are quite efficient: Read and translate into Vietnamese sewage, treatment, environment, awareness, rudimentary, discharge, self-purification, settling chambers, gritty, skimmer, grease, debris, shred, sludge, flocculation, biochemical oxygen demand BOD , ecology, bacteria, metabolize, incubation B.
Give the definition of sewage. Why does the sewage have to be treated? Tell something of primary treatment of sewage? What is BOD? Why does the sewage have to carry out secondary treatment after primary treatment? In actual practice the chemical engineer is principally concerned either with physical operations entirely or with the purely physical effects of chemical reactions, such as the transport of solids, fluid flow, mixing and agitation, heat transfer, etc. To obtain the product of a chemical reaction in a marketable form further operations may be involved, such as filtration, crystallization, distillation, evaporation, drying, and grinding.
These, in fact, are also physical operations, and the indicating appliances used to control them are usually based on physical rather than on chemical principles. One of the most important contributions of the chemical engineer is to guide industry in the choice of materials for the construction of plant. The chemical engineer can select materials suitable for each particular part of the plant, with consequent improvement in the life of the apparatus and general economy in working.
Examples may be found in the development of metals capable of resisting corrosion, chemical reagents, heat and creep at high temperatures. New processes call for new technique in plant design.
Today there is much talk of the production of motor spirit and other oils by high-pressure reactions. Such developments would still be at the laboratory stage had it not been for the work of the chemical engineer in taking advantage of the development of high-tensile steel and then applying his special knowledge to the design of new kinds of plant in which hydrogen and other gases and vapors are handled at high pressure and temperatures.
Thus, commercial success in translating a laboratory method of a preparation into a full-scale manufacturing process depends as much upon the careful plant design as upon consideration of the precise chemical reactions to be employed; in short, industrial efficiency and the profits expected to accompany this can only be realized by sound chemical engineering. Read and translate into Vietnamese engineering, branches, physical operations, agitation, heat transfer, marketable form, grinding, drying, evaporation, crystallization, construction, reagents, creep, motospirit, full-scale, sound chemical engineering B.
What is the chemical engineering concerned? What is the most important contribution of the chemical engineer? Can you tell some main operations involved in the industrial process?
What is the commercial success of scientific research of chemical reaction? How can you get the industrial efficiency? A typical bituminous coal has the following composition: The series of operations involved in gas manufacture includes the processes of distillation, condensation of the products of distillation which are liquid or solid at atmospheric temperature, exhaustion of the uncondensed gas from the retorts, wet purification, by washing with water, dry purification, estimation of the volume of the purified gas, and distribution to the mains from which the customer draws his supply.
The distillation of coal is carried out by the following systems: Horizontal retorts 2. Continuously operated vertical retorts 3. Intermittent vertical retorts of chambers 4. Coke ovens: Most of the town gas supplied by the gas industry is made in horizontal or vertical retorts.
Vertical Retorts - Carbonization in vertical retorts may be continuous or intermittent. In the case of the former coal is fed continuously into the top of a retort by means of gravity, and is carbonized in its passage through the retort, coke being extracted by a slowly moving extractor at the base. As the coal is carbonized it swells considerably, and in consequence the retorts are wider in both dimensions at the bottoms than at the top.
The retorts in cross-section are either rectangular or oval and are of various sizes to carbonize from 3 to 12 tons per day. The actual amount of coal passing through the retort depends upon the class of coal being carbonized and the calorific value of the gas produced. Steam is introduced at the base of the retort for the primary purpose of cooling the coke before it is discharge, but in so doing it produces water gas, thus increasing the gaseous yield.
With continuous vertical retorts there is great possibility of flexibility in output and calorific value through variations in the rate at which coal is carbonized and in the amount of steaming. Steam is generated in waste-heat boilers in which the heat of the waste gases in utilized. From the retort the gas passes to the hydraulic main.
It leaves the main at a temperature of about C, and is reduced to the temperature of the air by condensers which are air-cooled or water-cooled, or both. It is then subjected to purification and passed to the gas holder where it is stored. Read and translate into Vietnamese gas manufacture, condensation, atmospheric temperature, exhaustion, retorts, wet purification, estimation, distribution, horizontal retorts, vertical retorts, coke oven, extractor, carbonize, cross-section, rectangular or oval form, flexibility, hydraulic main, calorific value B.
What are the main composition of a typical bituminous coal? Can you tell the systems for the distillation of coal in the gas manufacture?
What is the vertical retort? What is the difference between the vertical retort and continuous vertical one? What is concept of air-cooled or water-cooled apparatus?
It is a heavy, oily liquid, density 1. This is the ordinary concentrated sulfuric acid of commerce. Concentrated sulfuric acid is very corrosive. It has a strong affinity for water, and a large amount of heat is liberated when it is mixed with water, as the result of the formation of hydronium ion: The Manufacture of Sulfuric Acid Sulfuric acid is made by two processes, the contact process and the lead-chamber process, which are now about equally important.
The gas containing sulfur trioxide is bubbled through sulfuric acid, which absorbs the sulfur trioxide. The principle of the lead-chamber process is shown by the following experiment.
A large flask is fitted with four inlet tubes and a small outlet tube. Three of the tubes come from wash bottles, and the fourth from a flask in which water may be boiled.
When steam is sent into the flask by boiling the water in the small flask, the crystals react to form drops of sulfuric acid, liberating oxides of nitrogen, which serve to catalyze the oxidation of sulfur dioxide by oxygen. In practice the reactions take place in large lead-lined chambers.
The Uses of Sulfuric Acid Sulfuric acid is used for the manufacture of soluble phosphate fertilizers and in the manufacture of many chemicals and drugs. It is also used as the electrolyte in ordinary storage cells, and hot concentrated sulfuric acid is an effective oxidizing agent.
Read and translate into Vietnamese sulfuric acid, density, droplet, yield, sulfur trioxide, affinity, hydronium ion, pour, apt to, sputter, container, catalytic oxidation, bubble, fertilizer, electrolyte, drug B. What is the sulfuric acid? What is the b. Can you describe the method for the manufacture of sulfuric acid? What is the main principle of the lead-chamber process? Give examples of some usages of sulfuric acid.
GLASS Glass is generally a mixture of several silicates, produced by melting together silica, an alkali and lime or lead. There are two general kinds of glass: The former is the more common, is cheaper, harder, more resistive and less fusible than lead glass.
The latter has greater luster and brilliancy and is used chiefly for cut-ware and optical purposes. In general, the higher the percentage of silica the harder, less fusible, and more brittle the glass. Fusibility is decreased and hardness increased by increasing the lime. In colored glass a part of the lime and lead is replaced by oxides of iron, manganese, cobalt, etc. The addition of borates and phosphates improves glass for various optical and chemical purposes, as do also zinc and barium.
German optical glass contains both zinc and barium. Practically all glass is decolorized in manufacture by the addition of manganese dioxide. Window glass is generally a soda-lime glass and, formerly, was always blown. Plate glass is usually soda-lime glass cast on large iron plates and subsequently ground and polished.
Ground plate glass is extensively used for flooring. Pressed glass is made by forming heat-softened glass to shape in dies under pressure. It is fairly inexpensive. Wire glass is glass having an iron wire screen thoroughly embedded in it. It is used for flooring, fireproof doors, etc. Pyrex glass is a low-expansion boro- silicate containing no metals of the magnesia-lime-zinc group and no heavy metals.
Principal uses are chemical ware, baking ware, high-tension insulators, sight glasses for chemical apparatus, glass pipe lines for chemical plants, etc. Owing to the low coefficient of expansion Pyrex glass withstands sudden changes of temperature without breaking.
Safety glass consist of two layers of plate glass firmly held by an intermediate layer of celluloid, attached to the glass by a suitable adhesive. It can be struck by a sharp hammer blow without shattering, and when sufficiently thick is practically bulletproof.
Read and translate into Vietnamese glass, silicate, silica, lime-glass, lead-glass, resistive, fusible, luster, brilliance, cut-ware, optical purposes, brittle, feasibility, soda-lime, cast, wire glass, embed, resistance, fireproof, insulator, adhesive, shattering, bulletproof B. What is the glass? How many kinds of glass do you know? And what are they? What are the difference of lime glass and lead glass?
Can you tell something about the safety glass? Say few words about the production of glass?
The method is based on the use of a high-frequency generator which offers the possibility of heating the reactants to high temps. The mineral sample is ground to particle sizes of 0. Then 0.
Then 1. CaCl2 is added. The crucible is heated in a furnace at for 20 min. To remove H2O absorbed during weighing. After this the crucible is lowered into a dry quartz tube which is closed with a rubber stopper. The quartz tube is placed in a cooling jacket of running H2O.
The temp. As a result all the alk. This reaction is completed after several min. Later complete dissolving of the salts from the crucible requires about 3 hrs. The soln. One difficulty encountered was the masking of the emission from K by an excess of Ca.
An expt. Microcline was used as the mineral. It was found that complete extn. A study of reproducibility of results was made by using Microcline, muscovite and biotite.
In comparing the rapid new method with the usual methods for detg. K in minerals, It was found that the K content obtained was higher with the new method. Preliminary studies on using the new method in rock analysis have given entirely satisfactory results. A sketch of the app. Read and translate into Vietnamese detn. What is the rapid method for determination of potassium? What are the particle size of mineral sample after grinding?
Tell some steps of preliminary studies on using a new method in rock analysis? Write and read all words in abbreviations in the lesson. By the use of these isotopes an element can be observed in the presence of large quantities of the same element.
For example, one of the earliest uses of tracers was the experimental determination of the rate at which lead atoms move around through a crystalline sample of the metal lead.
This phenomenon is called self-diffusion. If some radioactive lead is placed as a surface layer on a sheet of lead, and sample is allowed to stand for a while, it can then be cut up into thin sections parallel to the original surface layer, and the radioactivity present in each section can be measured.
The presence of radioactivity in layers other than the original surface layer shows that lead atoms from the surface layer have diffused through the metal. Perhaps the greatest use for isotopes as tracers will be in the field of biology and medicine. The human body contains such large amounts of the elements carbon, hydrogen, nitrogen, oxygen, sulfur, etc.
An organic compound containing a radioactive isotope, however, can be traced through the body. An especially useful radioactive isotope for these purposes is carbon This isotope of carbon has a half-life of about years. It undergoes slow decomposition with emission of beta rays, and the amount of the isotope in a sample can be followed by measuring the beta activity. Large quantities of C14 can be readily made in a uranium pile, by the action of slow neutrons on nitrogen.
The process can be carried out by running a solution of ammonium nitrate into the uranium pile, where it is exposed to neutrons. The carbon which is made in this way is in the form of bicarbonate ion, and can be precipitated as barium carbonate by adding http: Read and translate into Vietnamese radioactive, non-radioactive, isotope, traces, phenomenon, self-diffusion, determination, surface layer, sheet, parallel, radioactivity, biology, medicine, pile, expose to, bicarbonate B.
What is an extremely valuable technique for research in recent years? What is the phenomenon called self-diffusion? Can you cite some usage of isotopes as tracers in the body? How many elements are there in the body? Is it difficult to determine the state of the organic material in the body.
It is a colorless, mobile, flammable liquid with a mildly pungent and somewhat aromatic odor.
47. Ngon ngu co the.pdf
It is miscible in all proportions with water and with organic solvents such as ether, methanol, ethyl alcohol, and esters. Acetone is used chiefly as a solvent and as a raw material for the synthesis of organic compounds. Acetone is not easily oxidized; it is unaffected by nitric acid at room temperature and is stable to neutral permanganate. The more powerful oxidizing agents, such as alkaline permanganate and chromic acid, break it down to acetic and formic acid, and the latter decomposes further to carbon dioxide and water.
Acetone does not reduce ammoniacal silver or Fehling's solution. The flash point of acetone is C. Acetone occurs in small quantities in human blood and urine. It is also formed by thermal decomposition of coal peat, acetic acid salts, formates, and citric acid, and by the dry distillation of sugars with lime. The largest use of acetone is in the production of acetic anhydride, which in turn is chiefly consumed in making cellulose acetate for acetate rayon, photographic film, and plastics.
Acetone is also an excellent solvent for nitrocellulose and is used in making films, cements, artificial leather, and other similar products. By far the largest production of acetone is from petroleum-derived propylene by way of isopropyl alcohol. The production of acetone from isopropyl alcohol may be conducted either by catalytic dehydrogenation or by catalytic oxidation. The oxidation, being exothermic, is difficult to control; typical catalysts are copper, copper alloys, silver, and metal oxides, and temperatures are in the range to C.
The availability of high-quality acetone in large quantities from the petroleum chemical industry has been a major factor in the expansion of rayon production and other acetone-consuming industries in recent years.
Read and translate into Vietnamese acetone, ketone, pungent, aromatic odor, organic solvents, ether, methanol, ethyl alcohol, ester, synthesis, unaffect, permanganate, flash point, coal peat, lime, cellulose acetate, photographic film, plastics, dehydrogenation, promoters, exothermic, petroleum B. What is acetone?
What is acetone chiefly used for? Does acetone occur in human body? What is the largest usage of acetone? Describe some methods of production of acetone. It is best known as the chief acid constituent of vinegar. When cooled to below 16 degrees, pure acetic acid forms colorless crystals. These crystals resemble ice in appearance; hence the pure acid is usually called "glacial" acetic acid. There are many ways to prepare acetic acid.
It can be obtained by the oxidation of ethyl alcohol which in turn is prepared by fermentation. Or, it can be obtained from cider vinegar which is prepared from the juice of apples. For a long time acetic acid was produced by the distillation of wood. Seven gallons of acid were extracted from one ton of wood. Acetic acid is also produced by synthetic methods. One such method employs acetylene as the starting point which itself is obtained as a by-product in the production of hydrogen during the refining of petroleum.
The acetylene is passed through a dilute solution of sulfuric acid containing a catalyst. Acetaldehyde is formed by this reaction and is then oxidized to acetic acid. The most convenient way to prepare glacial acetic acid in the Lab is by the distillation of sodium acetate with sulfuric acid.
Place 10 grams of sodium acetate in an evaporating dish. Apply gentle heat and continue heating, with stirring, until the water of crystallization is driven off and a dry powder remains. Be very careful not to heat too strongly, as the compound will decompose and char. Transfer the powder to a flask and add 7 cc. If a condenser is available, fit it quickly to the flask.
If not, substitute a one-hole stopper and glass tubing leading to another vessel immersed in ice water. Heat gently. Acetic acid distils over and collects in the receiving container. If you care to purify the acid, it must be distilled again and that potion boiling at about degrees should be collected.
To demonstrate how easily acetic acid freezes, immerse a partially filled test tube of the pure acid forms salts. For example, neutralization with sodium carbonate will produce sodium acetate. And, using calcium carbonate, calcium acetate is obtained. By heating dry calcium acetate, acetone is produced. Similarly, ammonia will produce ammonium acetate and from this compound acetamide is prepared. With organic alcohols, acetic acid forms esters.
Read and translate into Vietnamese familiar, constituent, vinegar, in appearance, glacial acetic acid, fermentation, cider, juice, of apples, acetylene, refining, gentle, chat, acetaldehyde, decompose, vessel, immerse, collect, receiving, container, neutralization B.
What is the acetic acid? Where can you see acetic acid every day? Can you describe one of the methods for preparing acetic acid? What is the most convenient way for preparing glacial acetic acid in the lab.? Say a few words about acetic acid in your own way. The joints in the apparatus are made of asbestos paper covered with water glass. Eight grams of iron powder is added through the side neck to the stirred nitrobenzene.
From the separatory funnel 60 cc of bromine is added at such a rate that the bromine vapors do not traverse the condenser. This addition requires about one hour, and the mixture is stirred and heated for another hour before the addition of a second portion of iron and bromine.
Two portion, each of 8g of iron powder and 60 cc of bromine, are added under the same conditions as the first addition, and the mixture is stirred and heated for one hour between the completion of one addition and the beginning of another.
The evolution of hydrogen bromide slackens considerably toward the last of the heating, and there is practically no more bromine vapor in the condenser. A final addition of 2g of iron powder is made, and the heating continued for one hour longer.
The reaction product, which is a dark reddish-brown liquid, is poured or siphoned into 1. The mixture is distilled with steam and the first portion of the distillate is collected separately to remove a small amount of unchanged nitrobenzene. It is necessary to collect about 12 l of distillate in order to obtain all the m- Bromonitrobenzene.
The yellow crystalline solid is filtered with suction and pressed well on the funnel to remove water and traces of nitrobenzene. Learn Hawaiian ngon ngu co the Drops. With our new preview feature, you can now customize topics to improve your learning experience!
However, those who hold their hands at their sides or otherwise remain still while speaking are deemed colf and analytical. Over gesturing can also be problematic. Someone with arms that flail during communication, especially when hands become raised over the head, ngon ngu co the be seen as out of control.
Certain actions performed with the hands can also give off the wrong impression. Resting or propping your face up with your hands can indicate boredom. Fidgeting with your hands or playing with objects tends to display nervousness. Inspecting ones fingernails or especially checking your watch also ngon ngu co the disinterest.
Finally, picking a piece of lint off your shirt, especially while looking down, can signal disapproval.Work the chemicals into the rubber by kneading with the pestle. It is generally used as household and industrial fuel. This effect of the speeding up of the reaction is due to the vigorous catalytic action of the products of permanganate ion reduction: However, those who hold their hands at their sides or otherwise remain still while speaking are deemed colf and analytical.
Their exclusion has probably been due primarily to the combination of their origin, large size, simple product structure, and well-defined markets.
Read and translate into Vietnamese kettle, tank, accessories, autoclave, agitate, mixture, stirrers, circulating, jacket, coils, petroleum, roof, furnace, endothermic, batch reactor, tubular, velocity http: What is the phenomenon called self-diffusion?