任务一 无机化学常用词汇（Words & Phrases of Inorganic Chemistry）
dissociation constant 解离常数
the periodic table元素周期表
van der waals bond范德华键
任务二 无机化学短文阅读(Readings of Inorganic Chemistry English)
Inorganic chemistry is the branch of chemistry concerned with the properties and reactions of inorganic compounds. This includes all chemical compounds except the many which are based upon chains or rings of carbon atoms, which are termed organic compounds and are studied under the separate heading of organic chemistry. The distinction between the two disciplines is not absolute and there is much overlap, most importantly in the sub-discipline of organometallic chemistry.
The bulk of inorganic compounds occur as salts, the combination of cations and anions joined by ionic bonding. Examples of cations are sodium Na+, and magnesium Mg2+ and examples of anions are oxide O2− and chloride Cl−. As salts are neutrally charged, these ions form compounds such as sodium oxide Na2O or magnesium chloride MgCl2. The ions are described by their oxidation state and their ease of formation can be inferred from the ionization potential (for cations) or from the electron affinity (anions) of the parent elements.
Important classes of inorganic compounds are the oxides, the carbonates, the sulfates and the halides. Many inorganic compounds are characterized by high melting points. Inorganic salts typically are poor conductors in the solid state. Another important feature is their solubility in e.g. water, and ease of crystallization. Where some salts (e.g. NaCl) are very soluble in water, others (e.g. SiO2) are not.
The simplest inorganic reaction is double displacement when in mixing of two salts the ions are swapped without a change in oxidation state. In redox reactions one reactant, the oxidant, lowers its oxidation state and another reactant, the reductant, has its oxidation state increased. The net result is an exchange of electrons. Electron exchange can occur indirectly as well, e.g. in batteries, a key concept in electrochemistry.
When one reactant contains hydrogen atoms, a reaction can take place by exchanging protons in acid-base chemistry. In a more general definition, an acid can be any chemical species capable of binding to electron pairs is called a Lewis acid; conversely any molecule that tends to donate an electron pair is referred to as a Lewis base. As a refinement of acid-base interactions, the HSAB theory takes into account polarizability and size of ions.
Inorganic compounds are found in nature as minerals. Soil may contain iron sulfide as pyrite or calcium sulfate as gypsum. Inorganic compounds are also found multitasking as biomolecules: as electrolytes (sodium chloride), in energy storage (ATP) or in construction (the polyphosphate backbone in DNA).
The first important man-made inorganic compound was ammonium nitrite for soil fertilization through the Haber process. Inorganic compounds are synthesized for use as catalysts such as vanadium(V) oxide and titanium(III) chloride, or as reagents in organic chemistry such as lithium aluminium hydride.
Subdivisions of inorganic chemistry are organometallic chemistry, cluster chemistry and bioinorganic chemistry. These fields are active areas of research in inorganic chemistry, aimed toward new catalysts, superconductors, and therapies.
任务三 有机化学常用的词汇（Words & Phrases of Organic Chemistry）
任务四 有机化学短文阅读(Readings of Organic Chemistry English)
The nature of Organic Chemistry has changed greatly since 1828. Before that time the scientific philosophy known as “Vitalis m” maintained that Organic Chemistry was the chemistry of living systems. It maintained that Organic Compounds could only be produced within living matter while Inorganic compounds were synthesized from non-living matter. Even the word “organic” comes from the same root as the word “organism” or “organ”. However people like Professor Wohler beginning in 1828 determined that it was indeed possible to synthesize organic compounds from those compounds that were considered inorganic. One of the first organic compounds synthesized from basically inorganic compounds was the compound Urea which is a metabolic product of urine. It was synthesized from Ammonium Cyanate considered a compound produced outside of living matter and therefore considered inorganic. Since then many millions of Organic compounds have been synthesized “in vitro” in other words outside living tissue.
The building block of structural organic chemistry is the tetravalent carbon atom. With few exceptions, carbon compounds can be formulated with four covalent bonds to each carbon, regardless of whether the combination is with carbon or some other element. The two-electron bond, which is illustrated by the carbon-hydrogen bonds in methane or ethane and the carbon-carbon bond in ethane, is called a single bond. In these and many related substances, each carbon is attached to four other atoms:
There exist, however, compounds such as ethene (ethylene), C2H4, in which two electrons from each of the carbon atoms are mutually shared, thereby producing two two-electron bonds, an arrangement which is called a double bond. Each carbon in ethene is attached to only three other atoms:
Similarly, in ethyne (acetylene), C2H2, three electrons from each carbon atom are mutually shared, producing three two-electron bonds, called a triple bond, in which each carbon is attached to only two other atoms:
By convention, a single straight line connecting the atomic symbols is used to represent a single (two-electron) bond, two such lines to represent a double (four-electron) bond, and three lines a triple (six-electron) bond. Representations of compounds by these symbols are called structural formulas; some examples are
To save space and time in the representation of organic structures, it is common practice to use “condensed formulas” in which the bonds are not shown explicitly. In using condensed formulas,normal atomic valences are understood throughout. Examples of condensed formulas are
Another type of abbreviation that often is used, particularly for ring compounds, dispenses with the symbols for carbon and hydrogen atoms and leaves only the lines in a structural formula. For instance, cyclopentane, C5H10, often is represented as a regular pentagon in which it is understood that each apex represents a carbon atom with the requisite number of hydrogens to satisfy the tetravalence of carbon:
任务五 分析化学常用词汇(Words & Phrases of Analytical Chemistry)
coefficient of variation变异系数
validation of methods方法的有效性
level of significance显著性水平
limit of quantitation定量限
relative standard deviation(RSD) 相对标准偏差
任务六 分析化学短文阅读(Readings of Analytical Chemistry English)
Analytical chemistry is the science of making quantitative measurements. In practice, quantifying analytes in a complex sample becomes an exercise in problem solving.
Titration is the quantitative measurement of an analyte in solution by completely reacting it with a reagent solution. The reagent is called the titrant and must either be prepared from a primary standard or be standardized versus a primary standard to know its exact concentration.
The point at which all of the analyte is consumed is the equivalence point. The number of moles of analyte is calculated from the volume of reagent that is required to react with all of the analyte, the titrant concentration, and the reaction stoichiometry.
The equivalence point is often determined by visual indicators are available for titrations based on acid-base neutralization, complexation, and redox reactions, and is determined by some type of indicator that is also present in the solution. For acid-base titrations, indicators are available that change color when the pH changes. When all of the analyte is neutralized, further addition of the titrant causes the pH of the solution to change causing the color of the indicator to change.
If the pH of an acid solution is plotted against the amount of base added during a titration, the shape of the graph is called a titration curve. All acid titration curves follow the same basic shapes.
Strong Acid Titration Curve
At the beginning, the solution has a low pH and climbs as the strong base is added. As the solution nears the point where all of the H+ are neutralized, the pH rises sharply and then levels out again as the solution becomes more basic as more OH- ions are added.
Manual titration is done with a buret, which is a long graduated tube to accurately deliver amounts of titrant. The amount of titrant used in the titration is found by reading the volume of titrant in the buret before beginning the titration and after reaching the endpoint. The difference in these readings is the volume of titrant to reach the endpoint. The most important factor for making accurate titrations is to read the buret volumes reproducibly. The figure shows how to do so by using the bottom of the meniscus to read the reagent volume in the buret.
The end point can be determined by an indicator as described above or by an instrumental method. The most common instrumental detection method is potentiometric detection. The equivalence point of an acid-base titration can be detected with a pH electrode. Titrations, such as complexation or precipitation, involving other ions can use an ion-selective electrode (ISE). UV-vis absorption spectroscopy is also common, especially for complexometric titrations where a subtle color change occurs.
For repetitive titrations, autotitrators with microprocessors are available that deliver the titrant, stop at the endpoint, and calculate the concentration of the analyte. The endpoint is usually detected by some type of electrochemical measurement. Some examples of titrations for which autotitrators are available include:
· Acid or base determination by pH measurement with potentiometric detection.
· Determination of water by Karl Fischer reagent (I2 and SO2 in methyl alcohol and pyridine) with coulometric detection.
· Determination of Cl in aqueous solution with phenylarsene oxide using amperometric detection.
explosive concentration limit
力和力矩force and moment
Oil and gas result mostly from dead microorganisms buried quickly in anoxic environments, where oxygen is so scarce that they do not decompose. This lack of oxygen enables them to maintain their hydrogen-carbon bonds, a necessary ingredient for the production of fossil fuels. Newly developing ocean basins, formed by plate tectonics and continental rifting (deformation), provide just the right conditions for rapid burial in anoxic waters. Rivers fill these basins with sediments carrying abundant organic remains. Because the basins have constricted water circulation, they also have lower oxygen levels than the open ocean.
Plate tectonics is also responsible for creating the "pressure cooker" that slowly matures the organics into oil and gas. This process usually takes millions ofyears, giving the oil and gas deposits time to migrate around the globe on the back of plate movements. Because these hydrocarbons are much more buoyant than water, they eventually force their way to the surface. Alternatively, rifting, collisions between landmasses, and other tectonic forces can free the mature oil and gas from deep within sedimentary basins and then trap these organic fluids in reservoirs before they escape to the earth's surface. We know these reservoirs as oil and gas fields.
The same plate tectonics that creates the locations and conditions for anoxic burial is also responsible for the geologic paths that these sedimentary basins subsequently take. Continental drift, subduction (where one plate thrusts under another) and collision with other continents provide the movement from swamps, river deltas and mild climates --- where most organics are deposited --- to the poles and deserts, where they have ended up today by coincidence.
Petrochemicals are generally chemical compounds derived from petroleum either by direct manufacture or by indirect manufacture as by-products from the variety of processes that are used during the refining of petroleum. Gasoline, kerosene, fuel oils, lubricating oils, waxes, asphalts, and the like are excluded from the definition of petrochemicals, since they are, not, in the true sense, chemical compounds but are in fact intimate mixtures of hydrocarbons.
The classification of materials such as petrochemicals is used to indicate the source of the chemical compounds, but it should be remembered that many common petrochemicals can be made from other sources, and the terminology is therefore a matter of source identification.
The manufacture of chemicals from petroleum is based on the ready response of the various compound types to basic chemical reactions, such as oxidation, halogenation, nitration, dehydrogenation, addition, polymerization, and alkylation. The low-molecular-weight paraffins and olefins, as found in natural gas and refinery gases, and the simple aromatic hydrocarbons have so far been of the most interest because it is these individual species that can readily be isolated and dealt with. A wide range of compounds is possible, many are being manufactured, and we are now progressing the stage in which a sizable group of products is being prepared from the heavier fractions of petroleum. For example, the various reactions of petroleum heavy ends, in particular the asphaltenes, indicate that these materials may be regarded as chemical entities and are able to participate in numerous chemical or physical conversions to, perhaps, more useful materials. The overall effect of these modifications is the production of materials that either afford good-grade aromatic cokes comparatively easily or the formation of products bearing functional groups that may be employed as a nonfuel material.