This is because sugar molecules contain regions of hydrogen-oxygen polar bonds, making it hydrophilic. Various mixtures of solutes and water are described in chemistry. The concentration of a given solute is the number of particles of that solute in a given space oxygen makes up about 21 percent of atmospheric air. Another method of measuring the concentration of a solute is by its molarilty—which is moles M of the molecules per liter L.
The mole of an element is its atomic weight, while a mole of a compound is the sum of the atomic weights of its components, called the molecular weight. An often-used example is calculating a mole of glucose, with the chemical formula C 6 H 12 O 6. Using the periodic table, the atomic weight of carbon C is Doing the same calculations for hydrogen H and oxygen O , the molecular weight equals When water is added to make one liter of solution, you have one mole 1M of glucose.
Many substances in the bloodstream and other tissue of the body are measured in thousandths of a mole, or millimoles mM. A colloid is a mixture that is somewhat like a heavy solution.
The solute particles consist of tiny clumps of molecules large enough to make the liquid mixture opaque because the particles are large enough to scatter light. Familiar examples of colloids are milk and cream. In the thyroid glands, the thyroid hormone is stored as a thick protein mixture also called a colloid. A suspension is a liquid mixture in which a heavier substance is suspended temporarily in a liquid, but over time, settles out.
This separation of particles from a suspension is called sedimentation. An example of sedimentation occurs in the blood test that establishes sedimentation rate, or sed rate. The test measures how quickly red blood cells in a test tube settle out of the watery portion of blood known as plasma over a set period of time. Rapid sedimentation of blood cells does not normally happen in the healthy body, but aspects of certain diseases can cause blood cells to clump together, and these heavy clumps of blood cells settle to the bottom of the test tube more quickly than do normal blood cells.
Two types of chemical reactions involve the creation or the consumption of water: dehydration synthesis and hydrolysis. These reactions are reversible, and play an important role in the chemistry of organic compounds which will be discussed shortly. Recall that salts are formed when ions form ionic bonds. In these reactions, one atom gives up one or more electrons, and thus becomes positively charged, whereas the other accepts one or more electrons and becomes negatively charged. This fact is important in distinguishing salts from acids and bases, discussed next.
A typical salt, NaCl, dissociates completely in water Figure 2. The positive and negative regions on the water molecule the hydrogen and oxygen ends respectively attract the negative chloride and positive sodium ions, pulling them away from each other. Again, whereas nonpolar and polar covalently bonded compounds break apart into molecules in solution, salts dissociate into ions.
These ions are electrolytes; they are capable of conducting an electrical current in solution. This property is critical to the function of ions in transmitting nerve impulses and prompting muscle contraction. Many other salts are important in the body. For example, bile salts produced by the liver help break apart dietary fats, and calcium phosphate salts form the mineral portion of teeth and bones.
Acids and bases, like salts, dissociate in water into electrolytes. Acids and bases can very much change the properties of the solutions in which they are dissolved. Because an atom of hydrogen has just one proton and one electron, a positively charged hydrogen ion is simply a proton. This solitary proton is highly likely to participate in chemical reactions. This strong acid aids in digestion and kills ingested microbes.
Weak acids do not ionize completely; that is, some of their hydrogen ions remain bonded within a compound in solution. An example of a weak acid is vinegar, or acetic acid; it is called acetate after it gives up a proton. The relative acidity or alkalinity of a solution can be indicated by its pH.
That is, a solution with a pH of 4 is ten times more acidic than a solution with a pH of 5. The concept of pH will begin to make more sense when you study the pH scale, like that shown in [link]. The scale consists of a series of increments ranging from 0 to Chapter 4. Chemistry PowerPoints. Astronomy e. Interact with other members Receive feedback from the Course-Notes. Organic Chemistry Notes. Unit 1: States of matter Everything is made of particles. MIT Dept. Lecture Notes. These revision notes include all of the content for Chemistry paper 1 from the new AQA specification.
Comments -1 Everything that has mass and occupies space is composed of atoms When you study chemistry, you should not view this as some type of a chore that the school system is forcing you through. Ch 15 Notes: Power Point. Therefore, the notes you take in class see below are very important. From aluminum to xenon, we explain the properties and composition of the substances that make up all matter.
Note the list of questions required is longer than those in the PDF lecture notes. Chemistry for most of the Pakistani students is difficult, but if you have all the content like notes, videos, and easy articles on the topics, this subject will be a piece of cake. Other notes have been used in the NSF Workshop on Theoretical and Computational Chemistry, a week-long workshop which introduces faculty at 2-year and 4-year colleges to modern techniques in chemical theory and computation for incorporation into their research, classroom teaching, and laboratory modules.
This page contains links to the PowerPoint presentations that I will be using in class and some that I no longer use. Proteins Hydrocarbons Soil Nitrogen IB Chemistry may not be quite as easy as this penguin makes it seems. Pdf files are larger take longer to download but will be readable by just about every computer with the Adobe Acrobat browser plug-in.
We will be covering the material in a first year introductory high school or college general chemistry course. A lot of this information is NOT included in your text book, which is a shame. PowerPoint Notes. Chapter 8. Notes for carbon and its compound chapter of class 10 science. Click here to download PowerPoint viewer. Search this site. I no longer recommend anyone to use my notes as the main material for your exam preparation as it does not reflect the requirement as stated in the latest syllabus.
Know the factors that characterize a compound as being a lipid. Biology c. Chapter 2. Nucleic Acids Groups Last Modified on September 7, Use these as a supplement to your own class notes or as a review. Spring Semester Polymers Organic chemistry is the chemistry of carbon compounds; inorganic chemistry is the chemistry of compounds of all elements other than carbon. Chapter 3. Review Sheets - Practice problems with answer keys and checklists of key concepts.
International baccalaureate chemistry web, an interactive IB syllabus with revision notes and worked past paper questions I get lots of questions about whether ChemRevise notes say everything that is needed to do well at A-level. There are many different types of organic compounds, but all have carbon as their principal constituent atom. Ideal vs. If you missed class or are just a little behind for whatever reason, these are the notes we use in class. Real Gases In order to behave as an ideal gas, gases could not have any volume and could be attracted to other gas molecules.
My General Chemistry Lecture Notes have been placed online see below and Internet visuals attached for some topics. Students from both Edexcel and CIE chemistry can use this website. William H. The Chemistry notes cover topics such as chemical bonding, qualitative analysis testing for cations, anions, and gases , organic chemistry, acids, bases, and salts, electrolysis, etc.
Chemistry Lecture 5. Introduction to Chemistry, Atoms and Elements Importance of Chemistry Question: If cataclysmic event were to destroy all knowledge of science what would be the most important knowledge to pass on to future generations? Answer: Everything is made of Atoms.
Ch 10 Notes: Power Point. For syllabus with current course information and homework problems find your course in UTC Learn Blackboard. Laws of chemical combination 2. These numbers are called magic numbers. Benzene The Readings column refers to relevant sections in the course textbook, L. Chemistry of Life 1 Life is a chemical process.
It covers the entire Chemistry form 3 syllabus, for the preparation of national and local exams. I ought to point out when I originally wrote these notes they were aimed as brief revision notes for my own students. They only "work" correctly if you view them on a computer or tablet running PowerPoint. The uses of organic compounds impact our lives daily in medicine, agriculture, and general life. Substitution reactions in organic chemistry are classified either as electrophilic or nucleophilic depending upon the reagent involved. Chemistry - the study of the properties of matter The fundamental unit of matter is the atom.
Problem : Nitrogen gas reacts with hydrogen gas to produce gaseous ammonia NH 3. Lecture Notes Lecture Notes for Inorganic Chemistry week 6 : Introduction Chromium case The elements and electronegativity week 7: Acidity constants of some organic molecules Acids and bases week 8: Coordination Chemistry: Geometry How to make a cardboard regular octahedron and how to fold one in Danish only week 9: Smart Notes Online is an educational platform that makes studying Smart, Easier, Better and Less-time consuming.
AP Chemistry builds on concepts covered in a regular or "honors" chemistry course, using greater detail in concept exploration and laboratory investigation. Matter is the substance of everything B. Teachers, please feel free to PowerPoint Presentations. Teachers, please feel free to use and modify them for your own classes. Chemical Kinetics Average vs. Matter is made up of very small indivisible particles called atoms. Chemical Kinetics. Ch 9 Notes: Power Point. Thermochemistry Lecture Notes During this unit of study, we will cover three main areas.
Particles in solid are not free to move around. Chapter 1. Use and alter these presentations freely or any power point template used in this presentations site for other tea Room is provided in the right-hand column for you to fill in with the reasons each step was taken. Classification of Elements and Periodicity in Properties. This textbook aims to provide a comprehensive set of basic notes in organic chemistry, which will be suitable for undergraduate students taking chemistry, chemistry-related courses, or courses which involve organic chemistry as an ancillary subject.
Purdue University General Chemistry Topics - Notes and practice problems on a large number of topics. Likewise, simple pictures of uninteresting and garden variety chemistry-related things are not appreciated. Results 1 - 10 Coordination Compounds I. Chemistry Policies and Procedures. A comprehensive review of the chemistry of aminoguanidine has been written by Lieber and Smith.
Thiele: Ann. Lieber and Smith: J. Soc, 58, Shreve and Carter: Intl. Heyn: French patent ; cf. Zieke: German patent ; cf. Abstracts, 35, Zieke and Hoffmann: German patent ; cf. Abstracts, 38, Lieber and Smith: Chem. Booth f and R. KiRKt Ammonium dithiocarbamate has been prepared by using the following organic solvents as diluents for the reaction between carbon disulfide and ammonia: esters; 1 alcohol; 2 ether and alcohol; 3 ketones; 4 ethers; 5 nitriles; 6 and nitro compounds.
Procedure A The rate of ammonia flow is carefully adjusted so that only a small excess passes out of the vent tube. Goodrich Co. When a tube of smaller diameter or a gas distribution tube is used, the flow of ammonia may be obstructed due to crystallization of the product. Commercial isopropyl acetate is usually sufficiently dry. If necessary, this solvent can be dried conveniently by stirring vigorously with ml.
Dry ammonia can be obtained by using the following procedure: Approximately ml. Metallic sodium is added in small pieces until a permanent dark blue color appears, then another small piece in excess. The flask is now closed with a one-hole rubber stopper from which a glass outlet tube and rubber tubing are led, first through a trap, and then to the ammonia inlet tube of the reaction flask. A steady flow of gaseous ammonia at the rate desired can now be obtained by placing an infrared bulb near the Dewar and regulating the distance of the bulb from the flask. Ammonium dithiocarbamate precipitates as a light yellow, crystalline product.
The progress of the reaction can be followed by occasion- ally weighing the complete equipment and noting the weight increase. If the proper ammonia addition rate is maintained so that carbon disulfide and isopropyl acetate are not carried out of the vent tube, the final weight increase will amount to approximately g. About 2 hours are required to add all the ammonia. Stirring is continued for 15 minutes after the ammonia addition has been completed. The slurry of ammonium dithiocarbam- ate is filtered on a Buchner funnel and is washed with petroleum ether or hexane to facilitate drying.
The product is dried as rapidly as possible at room temperature by stirring with a porcelain spatula. The dry weight is to g. For the preparation of an aqueous solution of ammonium dithiocarbamate, ml. The mix- ture is agitated for a few minutes and the light yellow water solution of ammonium dithiocarbamate lower layer is separated from isopropyl acetate. The yield can be deter- mined quite accurately by noting the increase in weight of the measured volume of water added.
Analysis Dilute copper II sulfate solution gives a yellow floccu- lent precipitate when added to a dilute solution of ammo- nium dithiocarbamate. If a dilute solution of dithiocarba- mate is heated to accelerate its decomposition, the resulting thiocyanate ion can be detected with iron III chloride. A good quantitative method for the determination of dithiocarbamate involves its precipitation as the sparingly soluble zinc salt. An alternative procedure involves igni- tion to zinc oxide.
In this method dithiocarbamic acid is quantitatively oxidized to thiuram disulfide. Properties Ammonium dithiocarbamate is an unstable, light yellow, crystalline solid. The melting point is not a suitable criterion for estimating the purity of ammonium dithio- carbamate because it melts with decomposition. The products of decomposition are ammonium thiocyanate, sulfur, and hydrogen sulfide. Under the same conditions, a water solution is stable for several weeks. Ammonium dithiocarbamate is useful in the synthesis of heterocyclic compounds, particularly mercaptothiazoles.
Mathes: U. Ziese: J. Debus: Ann. Muldkk: ibid. Fbkund and Bachrach: ibid. Delepine: Bull. Levi: Gazz. Miller: Contribs. Boyce Thompson Inst. Julian and Stubgis: J. Soc, 57, Abstracts, 34, Few elements show more individuality of chemical behavior. The general characteristics of organosilicon substances are 1 wide variation of reactivity in the carbon-silicon bond, depending upon the substituents on both atoms; 2 comparatively easy removal of halogens and acid radicals from the silicon by hydrolysis, but rather difficult removal from the carbon except in some favorable structures; 5 and 3 a decided tendency to form polymeric structures con- taining alternate silicon and oxygen or nitrogen or sulfur atoms.
This behavior indicates that silicon is quite elec- tropositive with respect to bonded carbon, 6 and sufficiently positive with respect to oxygen to make the siloxane bond about half ionic in character. Metallic carbides constitute a special case and are considered separately. Consequently, in this brief discussion the many other types of organic derivatives in which organic groups are linked to silicon through oxygen, sulfur, nitrogen, etc. A two-stage Wurtz reaction allows partial substitution. A mix- ture of substitution products is always obtained, from which the desired compounds must be isolated by distillation.
To these there have now been added some newer methods which offer particular advantages: 4. The method is best suited to the preparation of dialkyl- and diaryldihalogenosilanes, but if organo- trichlorosilanes are desired, a mixture of hydrogen chloride and alkyl chloride may be employed as reactant. Acetylene adds one equiva- lent of trichlorosilane to form vinyltrichlorosilane, which then may add another equivalent of the silane.
These methods embrace a wide variety of laboratory techniques, for 1 and 2 may be carried out in sealed tubes, 2, 3, 0, and 7 may be carried out in solution, 4 and 5 may be heterogeneous gas-phase reactions at elevated tempera- ture, and 7 may involve reactions in pressure vessels above the critical temperatures of the reactants. Hence it becomes impossible to state which method is best suited for the preparation of a desired compound; much will depend upon the available equipment and the experimenter's familiarity with the different techniques.
In general, the Grignard method is the most flexible and can be used for the introduc- tion of one to four groups on silicon with yields up to 70 per cent, using any group capable of forming a Grignard reagent. The Wurtz method is still convenient at times, especially for preparing completely substituted compounds.
Method 4 is best used for synthesizing dialkyldihalogeno- silanes, particularly with small alkyl groups, with which yields up to 70 per cent are obtainable. Method 6 is adapted to the attachment of large alkyl groups like tert- butyl, and method 7 provides an easy way to make alkyltrichlorosilanes from a wide variety of olefins.
Sil- anols may be made by hydrolyzing the corresponding halogenosilanes, and organosiloxanes result from the dehy- dration of silanols. Further reac- tions of the organic groups often are possible after the carbon-silicon bonds are established. Properties Extensive tables of the known organosilicon compounds and their properties are given in references 1 and 8. Since most organosilicon syntheses begin with the preparation of halogenosilanes or alkoxysilanes, the properties of these are of particular interest.
Almost all are colorless liquids that are sufficiently volatile to be purified by distillation, and all are subject to hydrolysis. The boiling points of most homologous series change regularly with composition, as in the phenylchlorosilanes: Table I Compound Boiling Point, mm. SiCI 4 It follows that in the preparation of new compounds the expected boiling points should not be inferred by inter- polation. The calculation of boiling points by the use of boiling-point numbers 24 is much more reliable.
Compounds of silicon with one, two, or three methyl groups and a complement of hydrolyzable atoms or groups are used to prepare the structural units of poly- methylpolysiloxanes 13 for silicone oil and rubber. Methyl- chlorosilanes also are used to provide water-repellent films on glass and cellulose, 14 and a variety of other organosilicon compounds may be similarly employed. Chlorosilanes and ethoxysilanes with alkyl and aryl groups that are particu- larly heat-stable and resistant to oxidation are hydrolyzed to polysiloxane "silicone" resins for insulation and pro- tective coatings.
Rules for naming organosilicon com- pounds have been adopted and published by Crane. Older literature will be found to follow widely divergent "systems," and hence the abstracts are scattered under many index names. The older reviews 18,19 are often helpful when abstracts fail. Burkhard, Rochow, Booth, and Hartt: Chem. Tables of all the known compounds and their properties are given, and the bibliography is complete to June 3, Bygden: "Silizium als Vertreter des Kohlenstoffs organisoher Verbin- dungen," inaugural dissertation, Upsala, Behaghel and Seibert: Ber.
Soc, 68, Wright and Hunter: ibid. Roth: ibid. Gilman and Clark: J. Soc, 69, Tyler, Sommeu, and Whitmore: ibid. Sommer, Pietrusza, and Whitmore: ibid. Burkhard and Krikble: ibid. Rochow: Trans. Soc, 90, Norton: Gen. Kilborne: Machine Design, 18, 8 , Crane: Chem. News, 24, Soiiumb and Saffi. Soc, 63, 93 Fross: ibid. Hurd and Rochow: ibid. TATLocKf Dimethyldichlorosilane may be prepared by the Grignanl reaction, but the sluggishness of the reaction of methyl chloride with magnesium and the low solubility of methyl- magnesium chloride in ether make the preparation more difficult.
The use of methyl bromide facilitates the reaction with magnesium but results in some undesired halogen exchange with silicon tetrachloride in the second stage. The other end is closed by a stopper bearing a short inlet tube and a ther- mometer with its bulb imbedded in the charge. The reaction tube is heated in an ordinary combustion furnace while a slow stream of methyl chloride 7 g. When the temperature! The contents of the trap and the receiver are then mixed and allowed to warm slowly; some unreacted methyl chlo- ride evaporates and leaves a mixture containing methyl- chlorosilanes, corresponding to a yield of approximately 90 per cent based on the methyl chloride that has undergone reaction.
This mixture is distilled at a high reflux ratio in a column of high efficiency, yielding the following fractions in approximately the proportions shown in the following table. Highest yields are obtained from a reactive mass made by pressing together copper and silicon powders and firing the pellets in hydrogen. Once begun, however, it is extremely vigorous and exothermal. Some 4. The products may be analyzed by hydrolyzing in a mix- ture of ice and ether and titrating liberated hydrochloric acid with standard base. Properties Dimethyldichlorosilane is a colorless liquid that freezes at — It hydrolyzesri-eadily in moist air and reacts with water to form a mixture of polymeric dimethylsiloxanes "methyl silicone" containing products possessing both cyclic and linear structures.
Kraure and von Grosse: "Die Ghemie der metallorganischcn Verbin- dungon," p. Rociiow: J. Hunter, Hyde, Warrick, and Fletcher: J. Patnoijm and Wii. Patnode: U. Abstracts, 39, RocHowf and W. Vinylchlorosilanes are prepared most conveniently from ethylchlorosilanes by a modification of the chlorination- dehydrochlorination reactions in which the dehydrohalo- genation is effected by a high-boiling tertiary amine.
Although the experimental procedure herein described is based on the preparation of vinyltrichlorosilane, the method can be adapted to the synthesis of many other vinyl silicon compounds. Procedure Caution : This reaction must be done in a hood! At this point about 4 g. Owing to the low boiling point of the mixture, activation of the reaction proceeds very slowly at first, but as the evolu- tion of gas continues and the amount of chlorinated product increases, the boiling point rises.
The commercial product was found to work well if it was freshly distilled just before using. Material standing for a day or two exposed to light and air was not satisfactory without redistillation. A good hood is a prime necessity for the chlorination reaction as large volumes of sulfur dioxide and hydrogen chloride are evolved. This also requires a reflux condenser of considerable capacity if loss of material is to be avoided. Toward the later stages of the reac- tion the boiling point rises quite sharply and increased heat will have to be supplied to keep the mixture boiling.
When this occurs an additional 2 g. Negligible amounts of the higher chlorinated products are found. One liter of dry, freshly distilled quinoline 2 f about 30 mol per cent in excess is placed in a Heat is evolved and a solid addition product settles out. The flask is transferred to a hot plate and is fitted with a water-cooled condenser on the outlet tube.
A thermometer is inserted through a cork in the neck of the flask which is then surrounded with an asbestos shield. Heat is applied slowly to the flask and the contents are brought to the boiling point. Other tertiary amines, e. The reac- tion products distill over and are collected in a clean bottle. A yield of g. In similar fashion, vinylmethyldichlorosilane may be prepared from ethylmethyldichlorosilane 35 per cent yield , and divinyldichlorosilane can be synthesized from diethyldichlorosilane with somewhat smaller yields.
Ethyl- trimethylsilane may in like manner be converted to vinyltrimethylsilane. Its specific gravity is 1. It hydro- lyzes in water or in moist air to form hydrogen chloride and an insoluble "vinyl silicone" gel.
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Hubd: J. Ushakov and Itenberg: J. Kipping: Proc. Soc, 20, 15 Disposal of the flask is recommended. Clean separation evidently requires a more efficient column. On standing, a small amount of crystalline precipitate may appear in the redistilled vinyltrichlorosilane W. TATLOCKf Diphenylsilanediol is an easily synthesized compound that finds use in the preparation of the cyclic diphenyl- siloxane polymers "phenyl silicone".
It may be pre- pared by hydrolyzing diphenyldichlorosilane, using a two- phase hydrolysis mixture consisting of toluene, tert-amyl alcohol, and water, The resulting diol is stable at room temperature. The diphenyldichlorosilane can be prepared by the reaction of chlorobenzene and silver-silicon alloy, 6 or by the Grignard reaction, involving interaction of a phenyl- magnesium halide with silicon tetrachloride. About Yi hour is required for addition of the chloride, after which the solution is stirred for another 10 minutes. The solution is then filtered by suction; the crystals are washed with water, until free from acid, and air-dried.
These crystals are essentially free from polymeric materials. Further purification may be effected by dissolving the prod- uct in warm methylethyl ketone, adding chloroform until crystals form, warming gently to bring these back in solution, and setting aside the clear solution until crystallization has taken place. The yield is g. Soc, 28, Kipping and Robison: ibid. Hyde and Dklong: J. Soc, 63, Rochow and Gilliam: ibid. IlENEGHANf Although germanium II iodide may be prepared by the reaction of germanium II sulfide with concentrated hydri- odic acid, 1 the procedure is complicated by the rather involved preliminary preparation of the sulfide.
Ger- manium IV iodide is readily obtainable from the oxide. One opening is fitted with a reflux condenser, another with a mechanical stirrer, and the third with a glass stopper. Ten milliliters of colorless, 57 per cent hydriodic acid and 20 ml. After the addition of 7. The mixture is then heated to boiling under reflux. In a short time, the red crystals of germanium IV iodide will have been converted into the yellow plates of germanium II iodide.
Any unreduced germanium IY iodide is removed by sub- limation in this process. Flood, Foster, and Pietrusza: Inorganic Syntheses, 2, Foster: ibid. Foster and Williston: ibid. L Godfrey, f and L. Foster t Checked hy A. LaubengayehJ and B. The filtrate, obtained after removal of germanium II iodide, is transferred to a ml. The liberated iodine is volatilized from the gently boiling mixture and may be collected. Pure white germanium IV sulfide is precipitated. Procedure Ten grams of germanium II iodide is introduced into a heavy-wall pyrex ampoule and attached by means of a Fig.
Apparatus for the preparation of methylgermanium triiodide. The ampoule is provided with a side tube into which excess methyl iodide may be distilled and recovered when the reaction is complete. After the air has been exhausted, the ampoule is immersed in a cooling mixture Dry Ice and isopropyl alcohol , and 2. The initial pressure is high and the ampoule may explode if its walls are thin. As reaction takes place, the yellow crystals of germanium II iodide disappear gradually, and a clear yellow liquid remains. If the iodide contains oxide, this will remain undissolved.
When cooled the entire product becomes solid, unless too great an excess of methyl iodide has been used. After cooling, the excess methyl iodide is removed by immersing the side arm of the ampoule in a cooling mixture, and then sealing it off. The bottom por- tion of the reaction ampoule is cracked off and placed in a suitable apparatus for purification and recovery of the product by distillation. During this process residual methyl iodide may first be removed; nonvolatile con- taminants remain behind. The yield is nearly quantitative.
Analysis Iodine content is determined by precipitation as silver iodide from an aqueous solution of methylgermanium tri- iodide. Germanium is determined by oxidation with mixed nitric and sulfuric acids, followed by ignition to germa- nium IV oxide. Found: Ge, Properties Methylgermanium triiodide is a lemon-yellow solid m.
Its crystals are anisotropic, biaxial negative, and probably rhombohedral. The color deepens to red as the tem- perature rises, but returns to yellow as the sample cools. It is soluble in water with extensive hydrolysis, and is ammonolyzed in liquid ammonia. Methylgermanium triiodide hydrolyzes in a limited amount of water to a mass of white needles that apparently constitute a crystalline form of methylgermanium oxide. Refluxing methylgermanium triiodide with 30 per cent hydrogen peroxide, followed by sublimation of the liberated iodine, leaves an aqueous solution of the oxide from which a glassy solid may be obtained by evaporation.
The glassy or amorphous material is a mixture of polymers of the empirical composition CH 3 GeOi. Hydrogen sulfide precipitates white methyl- germanium sulfide from an acidified solution of the oxide, and hydrogen peroxide reconverts the sulfide to the oxide. Both compounds are difficult to oxidize completely, even at high temperatures. Flood: J.
Soc, 55, Conard Fernelius, t and Laurence L. This direct precipitation procedure has not been used heretofore because of the gelatinous character of the usual phosphate precipitate, and the lack of a convenient method for con- verting the insoluble phosphates to soluble compounds for reprecipitation. These difficulties are overcome in the following process.
Raw Material An altered zircon, cyrtolite, which is a hydrated zirco- nium silicate in which part of the zirconium is replaced by hafnium, and divalent and trivalent metals, is used as the raw material. This ore, although not very abundant, is used as the source material rather than the zircon or baddeleyite 1 because of its higher hafnium content 5 to 9 per cent compared to 2 per cent or less for the normal ores , and 2 because it is easily susceptible to acid attack. Ordinarily silicates are not easily attacked by acid treat- ment and must be handled by some fusion method.
Extraction The massive cyrtolite is crushed in a jaw crusher and pul- verized in a ball mill. Two hundred grams of mesh ore and g. The heating process is continued for 10 minutes or until a stiff mud results. At this point heat- ing is discontinued and the cracked ore is cooled before it is added to 1 1. Twenty milli- liters of a 10 per cent glue solution is added to aid in the coagulation and filtration of the insoluble residue. The solution is filtered on a Biichner funnel and the residue washed with ml. The filtrates are combined. Treatment of the residue with sulfuric acid under the same conditions should not result in any further loss in weight.
If larger equipment is available the extraction may be run with multiples of the indicated quantities. The extraction of 1 kg. The solutions from combined extractions are ana- lyzed for total acid, total R0 2 and Hf0 2. Analytical Methods Hafnium Content. The hafnium concentration is best determined by the method of Claasen 9 as modified by Schumb and Pittman, 6 Willard and Freund, 4 and the checkers of this synthesis.
An aliquot of the zirconium hafnium solution that will provide about 1 g. An excess of ammonium hydroxide is added to precipitate the hydroxide. The precipitate is filtered, washed free of sulfate, and then dissolved in 10 ml. The solution is placed in a ml.
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The residue is treated with 15 ml. Approximately 1. The solution is treated with 7. After decomposition of the peroxide, the solution is diluted to ml. The precipitate is filtered on a Selas crucible, washed free of excess selenious acid with 2 1. Weighed portions 0. The per cent of hafnia is determined from the formula: Since this method has been found to be unreliable 3 for mixtures containing more than 85 per cent hafnia, it is not recom- mended as a method of analysis.
Total Oxide, R0 2. An aliquot of the zirconium hafnium solution that will provide approximately 0. Selas, Philadelphia, Pa. A 1- to 2-ml. From the titration data the total number of equivalents is calculated, and from the R0 2 and Hf0 2 data, the number of equivalents due to R0 2. The difference in these values yields the excess acid concentration. For large precipitations an earthenware crock is suitable Fig. The solution is kept in agitation by a motor-driven stirrer, shaft, and paddles, C, which are con- structed of an acid-resistant material such as Hastelloy.
Experi- ments have shown that the best results are obtained when the final suspen- sion contains not less than 0. Apparatus for pre- cipitation of zirconium hafnium phosphates. To obtain a satisfactory precipitate the reagents must be added at a rate not to exceed about 1 1.
Care must be taken to add both reagents at an equivalent rate. The rate of flow is checked by means of a drop counter inserted below the stop- cock of the separatory funnel, D. The precipitated phos- phates are separated from the mother liquor by filtration. Detail of atomizer arrangement for addition of reagents. Digestion 3 of the moist phosphates with a mixture of sodium hydroxide and sodium peroxide yields a dense white peroxy compound, which can be washed free from the soluble phosphates, and which is soluble in acid with the evolution of oxygen.
This reaction is utilized in the following procedure, except that 30 per cent hydrogen peroxide has been substituted for the sodium peroxide. The precipitated phosphate mixture is transferred to a Adsorbed acid is neutralized litmus with sodium hydroxide solution. To this mixture is added, with stirring, a cold concentrated 40 g. NaOH per mol of R0 2. At the end of this time the intermediate soluble peroxyzirconate hafnate should be completely decomposed to the insoluble peroxy compounds.
Washing by decantation is continued until the supernatant liquors no longer give a test for phos- phate. J The entire precipitate is then transferred to the filter to remove the remainder of the wash liquor. The precipitate is subsequently transferred to a beaker and dissolved in sufficient 1 : 1 sulfuric acid to give a 2 N sulfuric acid solution containing 2 to 5 per cent RO2 when finally diluted with water. The solution is then boiled to decompose the peroxide. A clear solution results if the precipitate has been washed free of phosphate; if a precipi- tate appears, it is best separated from the mother liquor by centrifugation and re-treated in the prescribed manner.
I The ammonium molybdate test is used. Care must be taken that all the reagents are phosphate-free. Fkactionation of Zikconium and Hafnium The mechanics of fractionation are the same as for com- plete precipitation except that an insufficient amount of precipitant is used. To determine what the optimum cut- off value for a given hafnia concentration should be, and to determine also what enrichment may be expected in each 1. Thus, knowing the hafnium content, the mol per cent of R0 2 to be precipitated is obtained from Fig. The number of grams of phosphoric acid necessary to precipitate this mol per cent of R0 2 as the phosphate is diluted with 2 N sulfuric acid to give the same volume as that of the 2 to 5 per cent zirconium hafnium oxysulfate which is also in 2 N acid.
At times it is more convenient to dilute the phosphoric acid to only a fraction of the volume of the zirconium oxysulfate solution to prevent excessive dilution of the phosphoric acid ; the rate of addition of the phosphoric acid must then be correspondingly reduced. Care must be taken that the rate of addition of the reagents is such that a constant fraction of the total R0 2 is removed throughout the precipitation.
Since the hafnium concen- 0. Comparison of optimum mol fraction of combined oxides precipitated and composition of starting material. By using the prediction curve Fig. However, since actual operating conditions are not as reproducible as would be desired, deviations from the predicted enrich- ment are observed. Since small changes are additive an appreciable error may result within a few steps.
It is therefore necessary to determine the hafnium content at frequent intervals. Starting with a raw material containing 0. Mother liquors of approximately equiva- lent concentration from the various steps are combined for re-treatment. The Preparation of Low-Hafnitjm Zirconia To prepare low-hafnium zirconia, the mother liquor from the first fractional precipitation is treated with ammonium hydroxide to precipitate the hydroxides, which are then filtered and redissolved in a calculated amount of moder- ately concentrated sulfuric acid.
This solution is then diluted with the amount of water required to give a 2 JV sulfuric acid solution that contains 5 per cent R0 2. From a fraction containing 0. Additional fractionations of the mother liquor will reduce the hafnium content to a concen- tration below the sensitivity of the arc spectrographic method used about 0. Because the impurities concentrate in the most soluble fraction, a com- plete phosphate precipitation is made on the final solution, the precipitate is washed with 2 N sulfuric acid, and then converted to the peroxy compound.
For final purification, the acid-soluble peroxy compound is dissolved in hydro- chloric acid, and the oxychloride prepared according to the procedure of Young and Arch.
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Coster and von Hevesy: U. Larsen, Fernelius, and Quill: Anal. Willard and Freund: Anal. Schumb and Pittman: Anal. Marquis, Urbain, and Urbain: Compt. Van Osdall: thesis, Ohio State University, Claasen: Z. Young and Arch: Inorganic Syntheses, 2, Nitrogen V oxide appears to have been first prepared in 1 by passing dry chlorine over dry silver nitrate heated on a water bath, the oxide being collected in solid form in a tube immersed in a freezing mixture. Subsequently, it was prepared by various investigators through dehydration of concentrated nitric acid by phosphorus V oxide.
A third method involves oxidation of the equilibrium mix- ture NO2-N2O4 with ozone. In earlier methods, phosphorus V oxide was added to the liquid acid. Procedure The apparatus for the preparation of nitrogen V oxide is shown in Fig. Oxygen is bubbled into bottle A con- To transformer Fjq.
Apparatus for tho preparation of nitrogen V oxide. The appa- ratus- is set up in a large hood. Ground-glass connections are advisable throughout, but if these are not available, cork stoppers coated with paraffin may be used. The acid is then thoroughly chilled in a deep-freeze unit. Saran tubing has been found to be fairly satisfactory, especially in that portion of the apparatus where tubing comes in contact with ozone. The acid in D is then frozen solid important by immersion of the flask in Dry Ice and alcohol. The passage of oxygen is continued during this operation.
Receiver E is also immersed in an alcohol and Dry Ice cooling bath and is connected to the system; oxygen is allowed to pass through for several minutes to remove moist air. About g. The ozonizer is put into operation prior to removal of the freezing bath. As the acid slowly melts, the liquid potion reacts with the large excess of phosphorus V oxide. When the initial intense reaction has subsided, the mass is stirred quickly and the reaction allowed to subside again. The warm water bath is now removed and ozonized oxy- gen allowed to circulate for an hour or more, depending upon the required degree of purity of nitrogen V oxide.
A yield of 42 g. Higher yields may be obtained at the expense of purity. With slow and careful distillation, it is possible to dispense with the ozonizer C, provided that an N 2 4 content of 10 to 20 per cent in the sub- limed crystals is not objectionable.
Inorganic Syntheses, Volume 9 | Inorganic Chemistry | Chemistry | Subjects | Wiley
It is readily soluble in cold chloroform a convenient method of using it without appreciable reaction and, to a lesser extent, in carbon tetrachloride. It is an extremely rapid, effi- cient, and safe nitrating agent in chloroform solution, when used in the presence of sodium fluoride as an adsorbent for the nitric acid by-product, 10 and offers interesting possi- bilities for continuous processes of nitration.
Deville: Compt. Weber: Pogg. Berthelot: Bull. Rubs and Pokorny: Monatsh. Daniels and Bright: J.
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